Lead-Alpha Age Determinations of Accessory Minerals of Igneous Rocks (1953-1957)

GEOLOGICAL SURVEY BULLETIN 1097-B

This report concerns work done in part on behalf of the U.S. Atomic Energy Commission and is published with the permission of the Commission

Lead-Alpha Age Determinations of Accessory Minerals of Igneous Rocks (1953-1957)By HOWARD W. JAFFE, DAVID GOTTFRIED, CLAUDE L. WARING

and HELEN W. WORTHING

STUDIES IN GEOCHRONOLOGY

GEOLOGICAL SURVEY BULLETIN 1097-B

This report concerns work done in part on behalf of the U.S. Atomic Energy Commission and is published with the permission of the Commission

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1959

UNITED STATES DEPARTMENT OF THE INTERIOR

FRED A. SEATON, Secretary

GEOLOGICAL SURVEY

Thomas B. Nolan, Director

For sale by the Superintendent of Documents, U.S. Government Printing Office Washington 25, D.C. - Price 30 cents (paper cover)

CONTENTSPage

Abstract _____-_-_-_____-__-_________-___________-____-___..-_-_-__ 65Introduction. _ ____________________________________________________ 65Acknowledgments. ______--_-______-_-________-_----____-__-___---.. 66Nature of the descriptive and experimental data_____________________ 67

Method of calculation of the age_--__-_--__--_-------_--_--_--_- 67Reproducibility of the age determination.________________________ 68Arrangement of the data in the tabulation____________________--__ 68

Lead-alpha age determinations of accessory minerals.__________________ 69Geographic index of localities.______________________________________ 140Literature cited.__________________________________________________ 145

ni

STUDIES IN GEOCHRONOLOGY

LEAD-ALPHA AGE DETERMINATIONS OF ACCESSOR? MINERALS OF IGNEOUS ROCKS (1953-1957)

By HOWARD W. JAFFE, DAVID GOTTFRIED, CLAUDE L. WARING, and HELEN W. WORTHING

ABSTRACT

The U.S. Geological Survey completed lead-alpha age determinations of accessory minerals from about 400 rocks between July 1953 and January 1957. All the ages and the experimental data, equations, and constants from which they were calculated are given in tabular form. A citation of the most probable geologic age of each rock is included for comparison with the measured age. The tabulation is followed by a geographic index of sample localities.

INTRODUCTION

Publication of the original report on the method of determining the age of igneous rocks from the lead-alpha ratios of their accessory minerals (Larsen and others, 1952) aroused considerable interest in the application of the method to the solution of geologic problems. Larsen has received numerous requests for age determination from geologists engaged in field mapping of areas where the age of intrusive rocks could not be established from field evidence because of poor paleontologic and stratigraphic control.

In July of 1953, the U.S. Geological Survey established a project to fill the numerous requests received for lead-alpha age determina­ tions. Since then, determinations have been completed on accessory minerals from about 400 rocks, most of which were submitted by geologists of the U.S. Geological Survey. A few samples were sub­ mitted by State and foreign geological surveys. Ages were deter­ mined of a variety of predominantly silicic to intermediate type igneous rocks representing most of the major bodies of intrusive rock in the United States. A limited number of determinations were also made on rocks from Mexico, Canada, Norway, Finland, France, Ceylon, Nyasaland, Formosa, Greenland, British Territories in Borneo, and Saudi Arabia.

A few determinations were made of detrital zircon from sedimentary rocks to obtain information of potential use in provenance studies. Although the geologist was advised against submitting metamorphic rocks because of the uncertainty in interpreting the results, some were received from those who believed that the age data might aid in the interpretation of the geologic history of an area.

65

66 STUDIES IN GEOCHRONOLOGY

The samples represented a geologic age span of Precambrian through late Tertiary. From periods after the Precambrian several rocks, whose geologic age has been established from good stratigraphic and paleontologic control, were either solicited from the field geologist or collected by the authors in the company of the field geologist in order to test the geologic consistency of the lead-alpha method. Many of the samples, however, represent intrusive bodies of question­ able to totally unknown geologic age. Although the determined ages of many of these rocks cannot be properly evaluated from geologic evidence, their publication at this time may provide useful information to geologists engaged in field mapping of related rocks and to other investigators in the field of geochronology.

ACKNOWLEDGMENTSThe authors are indebted to many of their colleagues in the U.S.

Geological Survey who collected large samples of a wide variety of igneous rocks for separation of accessory minerals used for the lead- alpha age determinations. These include P, C. Bateman, A. J. Boucot, G. F. Brown, R. S. Cannon, Jr., R. W. Chapman, R. C. Ellis, Carl Fries, Jr., J. T. Hack, D. F. Hewett, H. L. James, M. R. Klepper, E. S. Larsen, Jr., B. F. Leonard, T. S. Lovering, J. B. Lyons, J. J. Matzko, T. McCullough, H. T. Morris, T. B. Nolan, W. C. Overstreet, J. P. Owens, W. T. Pecora, George Phair, A. W. Postel, A. W. Quinn, J. F. Robertson, C. P. Ross, R. G. Schmidt, D. R. Shaw, R. L. Smith, W. L. Smith, and R. A. Weeks.

Many other geologists also gave generously of their time in the collection of samples for lead-alpha age work. These include A. F. Buddington and H. D. Holland, Princeton University; 0. Kuovo, University of Helsinki; R. L. Dott, Oklahoma Geological Survey; C. E. Tilley, Cambridge University; G. M. Schwartz, Minnesota Geological Survey; F. W. Roe, Geological Survey Department of British Territories in Borneo; P. T. Flawn, Bureau of Economic Geology of Texas; L. T. Silver, California Institute of Technology; T. F. W. Barth, University of Oslo; R. M. Hutchinson, Colorado School of Mines; G. A. Russell, Department of Mines and Natural Resources of Manitoba; and R. E. Folinsbee, University of Alberta.

The authors are greatly indebted to W. F. Outerbridge, W. L. Smith, R. P. Marquiss, George Hayfield, John Mangum, Theodore Woodward, and Carl Mayhew for the exacting job of separating and purifying hundreds of accessory mineral samples from igneous rocks.

The authors are grateful to E. S. Larsen, Jr., Earl Ingerson, R. M. Garrels, and Michael Fleischer for their guidance and cooperation in setting up the facilities required for the lead-alpha age program.

This work was done partly on behalf of the Division of Research of the U.S. Atomic Energy Commission.

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 67

NATURE OF THE DESCRIPTIVE AND EXPERIMENTAL DATA

This report presents a tabulation of the descriptive and experimental data on all the rocks whose age has been determined by the lead- alpha method. For each rock the data, wherever available, include : Index number Petrographic classification Sample number Geographic locality Collector of the sample Mineral used for age determination Mesh size of the crystals used for age determination Alpha activity of the mineral used for age determination Total lead content of the mineral used for age determination Lead-alpha age of the mineral Geologic age * of the rock from which the mineral was separated, based on geologic

evidence of the authority cited.

The citation of the geologic age was taken from published papers or from written communications, whichever incorporated the results of the most recent and complete field data for a given rock or area. In this way, the reader can readily note the degree of consistency or in­ consistency of the measured lead-alpha age with the geologic age assigned from stratigraphic, paleontologic, and field mapping investi­ gations. Where geologists disagree on the geologic age of a rock, both field age assignments are given with the respective references.

A comparison between the lead-alpha ages and ages obtained by isotopic methods is given by Gottfried and others (1959),

METHOD OF CALCULATION OF THE AGE

The lead-alpha ages reported herein were calculated from the age equations and constants given and evaluated by Gottfried and others from the measurements of the alpha activity and total lead content of each accessory mineral.

The age equations, repeated here for convenience of the reader, are as follows:

Range (millions of years) Equation

0-200 u a per mg per hr

200 1,700 t.=t-}4kp1,700 4,000 T=tf-

The constants, c and k are functions of the thorium to uranium rji l.ios of the different accessory minerals xenotime, zircon, and mona- zi l.e. The thorium to uranium ratio given for each mineral is an

» The term "geologic age" is used In this report to refer to the divisions of geologic time founded on strati- grnplilu-iwleontologie evidence, as opposed to age expressed in number of years.

68 STUDIES IN GEOCHRONOLOGY

average value selected from published analyses (Gottfried and others, 1959). These are as follows:

Selected Mineral thorium-uranium ratio e k (XIO7"4)

Xenotime__ __--_--_--___-__-__-__.___- 0.5 2,550 1.71Zircon____-_____._--.______.__.__..___ 1.0 2,485 1.56Monazite-_._____.___________ 25 2,085 .65

Where thorium and uranium have been experimentally determined for specific minerals included in the age tabulation, the c and k constants were obtained directly from the curves of Gottfried and others.

The ages measured on accessory minerals from rocks of well-estab­ lished geologic age have been evaluated by Gottfried and others (1959); Lyons and others (1957); Quinn and others (1957); and Larsen and others (1958). This report is principally a complete compilation of experimental lead-alpha age data obtained by the U. S. Geological Survey between 1953 and 1957.

The spectrographic lead determinations were made by Claude L. Waring and Helen W. Worthing. The alpha activity was determined by Howard W. Jaffe and David Gottfried.

Where duplicate or replicate lead determinations were made on a given sample of zircon, all the values are entered in the tabulation and the mean value is used hi the age calculation. All the lead- alpha age determinations are reported to two significant figures with the third and fourth figures hi italics.

REPRODUCIBILITY OP THE AGE DETERMINATION

Replicate age determinations were made of zircon from the same rock in 85 of the 411 rocks reported in the tabulation. Each age was reproducible to ±10 percent of the mean, or 10 million years, which­ ever is the greater, hi all but three of the rocks. In these three rocks each age was reproducible to only 10 to 34 percent of the mean. It is therefore reasonable to assume that, generally, any single age determination if repeated would be reproducible to ±10 percent of the mean or 10 million years. In a limited number of rocks, the age of more than one mineral has been measured. The agreement be­ tween the ages of zircon, monazite, and xenotime, separated from the same rock, is of the same order of reproducibility as obtained on dif­ ferent splits of zircon. The few determinations on thorite show a poorer agreement with cogenetic zircon.

ARRANGEMENT OF THE DATA IN THE TABULATION

The lead-alpha age determinations are listed in tabular form in a general order of increasing determined age. An attempt has been made to group data from petrographic and geographic provinces so that the entries do not always follow the strict numerical order of increasing age. An index number preceding each entry is provided for use hi a geographic index following the tabulation.

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 69

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5. 2

, 6.

3

2. 1

, 3.

4

5. 3

, 5.

5

Mea

n 3.75

7.6

5. 7

5

2.7

5.4

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears 47

49

38 38 53

37

Cite

d ge

olog

ic a

ge o

f the

ro

ck

No

data

. R

. J.

R

ober

ts.

Do.

Do.

Lat

e C

reta

ceou

s to

ea

rly

Ter

tiar

y.

E.

H.

Pam

peya

n.

Do.

Pos

t-L

ate

Cre

ta­

ceou

s (p

re-M

i-

ocen

e).

R.

Wil

l-

den.

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 75

i 5op

0

p n P

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toOJ

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to<3i

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O

Lea

d-al

pha

age

dete

rmin

atio

ns o

f ac

cess

ory

min

erals

Con

tinu

ed

No. 42 43 44

45 46

47

Eoc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

HT

M-2

. N

orth

L

ily

stoc

k,

1,25

0 fe

et

N.3

4°W

. of

Nor

th L

ily m

ine

shaf

t,

Eas

t T

inti

c di

stri

ct,

Uta

h.

H.

T.

Mor

ris.

HT

M-1

.S

ilve

r C

ity

stoc

k,

from

ra

il­

road

cut

nea

r th

e Ir

on D

uke

min

e, T

inti

c di

stri

ct,

Uta

h.

H.

T.

Mor

ris.

P-5

0-49

. B

ig

San

dy

Cre

ek,

Bea

rpaw

M

ount

ains

, M

ont.

W

. T

. P

ecor

a.

WT

P-3

. R

ocky

B

oy

stoc

k,

Peg

mat

ite

Pea

k,

Bea

rpaw

M

ount

ains

, M

ont.

W

. T

. P

ecor

a.

Dac

ite

.._

____

_ __

____

_

__S.

367

3.

Ban

, 1s

t D

ivis

ion,

Wes

t S

ara­

w

ak,

Bri

tish

T

erri

tori

es

in

Bor

neo.

F

. W

. R

oe.

Gra

nite

. _ _

____

____

____

____

__S

outh

368

6.

Min

eral

Zir

con _

__-_

--

__

_-_

do

_ ~

__

_-.

do

_-_

-__

-_-_

-do_--

_.-

_-_

__

__

.do

_ .

.._.

_ .do

Mes

h si

ze

-100+

200

-20

U+

40

0

-10

0+

20

0

-20

0 +

400

-80

+1

00

-1

00+

200

+20

-80+

200

-80+

200

a pe

r m

g pe

r hr 233

228

187

223

290

275

218

227

225

156

Lea

d (p

pm)

Det

erm

inat

ions

4.0

3.6

3.7

4

.5

5. 2

, 5.

G 5.

0, 5

. 1

5.6

4.0

3. 0

, 4.

0 5.

0,

6. 0

3. 0

, 2.

9

Mea

n

5.4

5

.05

4.5

2.9

5

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears 43

39 49

50 46

46 64

44 50

47

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Mid

dle

Eoc

ene

(Gre

en R

iver

).

H.

T.

Mor

ris,

T

. S.

Lev

erin

g.

Do.

Mid

dle

Eoc

ene

(Gre

en R

iver

).

Bro

wn

and

Pec

ora,

194

9.

Do.

Ter

tiar

y.

F.

W.

Roe

.

Ter

tiar

y (?

).

F.

W.

Roe

.

i o S CJ H

48 49 50 51 52

Tan

jong

D

atu,

1s

t D

ivis

ion

Wes

t S

araw

ak,

Bri

tish

Ter

­ ri

tori

es i

n B

orne

o.

F.

W.

Roe

.

alka

line

bas

alt.

T

PY

-1.

Nor

ther

n F

orm

osa.

T

. P

. Y

en.

4832

45.

Hach

ita

quadra

ngle

, S

EM

NE

M s

ec.

22,

T.2

9S.,

R.1

6W.,

sout

hwes

t N

ew

Mex

ico.

C

. D

ane.

1895

. F

lat

area

, F

lat

Cre

ek

near

S

tran

dber

g ca

bin,

1.

5 m

iles

no

rthw

est

of C

hick

en C

reek

, Id

itar

od q

uadr

angl

e, c

entr

al

Ala

ska.

P

. K

ille

en,

M.

Whi

te.

1810

. F

lat

area

, op

posi

te p

lace

r cu

t on

Chi

cken

Cre

ek,

Idit

arod

quad

rang

le,

cent

ral

Ala

ska.

P

. K

ille

en,

M.

Whi

te.

3469

.

Fli

nt

Cre

ek o

f th

e S

ulat

na

Riv

er,

Rub

y-P

oorm

an

dis­

tr

ict,

R

uby

quad

rang

le,

cent

ral

Ala

ska.

M

. W

hite

, J.

Ste

vens

.

....

_do

__ _

_--

___ d

o _

___ -_

% i

nch

crys

tals

.

-80+

200

-200+

400

-60

+1

00

-60+

100

-80

+ 2

00

21 250

275

334

315

1,36

61,

322

1,34

2

.4,.

4

4. 0

, 5.

05.

0,

6. 0

6. 2

, 7.

0

7. 8

, 7.

4

26,2

7 29 30

.4 4.5

5.5

6.6 7.6

26

.5

47 45 50

49 60 48 55 56

f

Pre

-Mio

cene

. ^

T.

P.

Yen

. b

Lat

e C

reta

ceou

s or

j£

Ter

tiar

y.

Las

ky,

^

1947

, p.

32-

33.

o O M

Lat

e or

pos

t-

gE

ocen

e.

Mer

tie

S

and

Har

ring

ton,

fej

19

24.

> o

Do.

§ M Q

O aM

esoz

oic(

?)

(pos

t-

^M

issi

ssip

pian

) .

§M

erti

e an

d H

ar-

fejri

ngto

n,

1924

. g

OQ

Lead

-alp

ha a

ge d

eter

min

atio

ns o

f acc

esso

ry m

iner

als

Con

tinu

ed

No. 53 54 55

56

57

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

5044

. N

ixon

F

ork

min

ing

dist

rict

, C

ryst

al S

haft

min

e, M

edfr

a qu

adra

ngle

, ce

ntra

l A

lask

a.

J. J

. M

atzk

o, G

. D

. E

berl

ein.

K

neeh

ills

tuf

f _

2415

. V

itri

c-cr

ysta

l tu

ff,

stre

am b

ed

of T

hree

hill

s C

reek

, 6

mil

es

nort

h

of

Car

bon,

A

lber

ta,

Can

ada.

R

. A

. F

olin

sbee

.

CP

R-1

20.

Dik

e fr

om

dike

zo

ne

alon

g S

outh

For

k, P

ayet

te R

iver

, w

est

of L

owm

an,

Idah

o.

B.

F.

Leo

nard

, C

. P

. R

oss.

CP

R-1

21.

Cam

as

Cre

ek

belo

w

Mye

rs

Cov

e,

Cas

to

quad

rang

le,

Idah

o.

B.

F.

Leo

nard

, C

. P

. R

oss.

P

orph

yrit

ic

biot

ite-

mus

covi

te

gra

nodio

rite

, so

mew

hat

gn

eiss

ic.

CP

R-1

22.

Nea

r Id

aho-

Mon

tana

li

ne,

Los

t H

orse

C

reek

, ne

ar

Ham

ilto

n, M

ont.

B

. F

. L

eona

rd,

C.

P.

Ros

s.

Min

eral

Zir

con_

__ _

____

__

____

_do.

___ _

_

_--_

_do_

--__

____

_____do -

----

____

.do _ _

____

_

Mon

azit

e.__

____

Mes

h si

ze

-60

+1

00

-100+

400

-20

0+

40

0

-80+

200

-400

-80+

200

-20

0+

40

0

-80

+2

00

-80+

200

a pe

r ing

pe

r hr 252

268

624

440

624

403

625

257

3,38

5

Lea

d (p

pm)

Det

erm

inat

ions

5. 8

, 6.

0

5. 5

, 6.

0

10,1

1 4.

2, 4

. 0

9. 0

, 11

9. 5

, 10

15

, 16

6. 0

, 7.

0

90,9

0

Mea

n 5.9

5.75

10.5

4.

1

10 9. 7

15

.5

6.5

90

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears 58

53 42

23

40 60

62 63

55

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Eoc

ene

or e

arly

O

ligoc

ene.

B

row

n, 1

926.

Ver

y L

ate

Cre

ta­

ceou

s (u

pper

par

t of

Edm

on-

ton f

orm

atio

n).

Fol

insb

ee a

nd

othe

rs,

1957

.

Mid

dle

Ter

tiar

y.

C.

P.

Ros

s.

Ter

tiar

y (

Mio

­ ce

ne) .

R

oss,

19

34.

Mid

dle

Ter

tiar

y.

And

erso

n, 1

951.

Cre

tace

ous.

R

oss,

19

52.

Lat

e C

reta

ceou

s or

ea

rly

Ter

tiar

y.

Lar

sen

and

Sch

mid

t, 19

58.

00 sa

o

3

o

F

o

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 79

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d-al

pha

age

dete

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atio

ns o

f ac

cess

ory

min

erals

Con

tinu

ed00 O

No. 65

66 67

68

Roc

k ty

pe

Fie

ld N

o.

Loc

ality

C

olle

ctor

55-im

-i.T

obac

co R

oot

bath

olit

h, n

ear

Hol

low

tow

n L

ake,

sou

thea

st

flan

k of

Mou

nt J

effe

rson

, 5

mile

s so

uthw

est

of

Pon

y,

Mon

t.

R.

R.

Rei

d.

Zir

con-

rich

"m

icro

-pla

cers

" in

da

cite

tuf

f.

55K

-307

a.

Of

Ter

tiar

y vo

lcan

ic

rock

s re

stin

g on

ero

ded

surf

ace

of

Bou

lder

ba

thol

ith,

O

beli

sk

min

e,

Jeff

erso

n C

ount

y,

Mon

t.

M.

R.

Kle

pper

. Q

uart

z m

onzo

nite

_ _

____

____

Z-2

.S

atel

liti

c st

ock

of t

he B

ould

er

bath

olit

h, M

onta

na.

R.

A.

Wee

ks.

Qua

rtz

mon

zoni

te__

_

_ __

_52

-C-1

0a.

Bou

lder

ba

thol

ith,

fr

om

the

bord

er

of

the

bath

olit

h,

7 m

iles

sout

heas

t of

H

elen

a,

Mon

t.

R.

W.

Cha

pman

.

Min

eral

__

__

_d

o

____

_do_

--_-

--_-

____

.do_

_-_-

___-

Mes

h si

ze

-80 +

400

-200 +

400

-80

+4

00

-80

+4

00

a pe

r m

g pe

r hr

493

192

336

160

Lea

d (p

pm)

Det

erm

inat

ions

13.

5

4. 2

, 4.

5

9. 0

, 10

4.6

Mea

n 4.3

5

9.5

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears 68

56 70

71

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Ear

ly T

erti

ary

or

Lat

e C

reta

­ ce

ous.

T

ansl

ey

and

othe

rs,

1933

.

Ter

tiar

y.

M.

R.

Kle

pper

.

Ver

y L

ate

Cre

ta­

ceou

s or

ver

y ea

rly

Ter

tiar

y (p

ost-

Judi

th

Riv

er,

pre-

earl

y O

ligoc

ene)

. K

nopf

, 19

57.

Do.

o

o

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 81

O

ft O

ftO

p -s.®

s

O CO

l><Ni-H

rHcc<N

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52-C-60.

Boulder batholith, roadcut miles northeast of Elk Par

Mont.

R. W. Chapman.

Alaskite

O r-lI> I>

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Near margin of the Bould batholith, Boulder H Springs, Jefferson Count

Mont. R. A. Weeks.

Lead

-alp

ha a

ge d

eter

min

atio

ns o

f acc

esso

ry m

iner

als

Con

tinu

ed

No. 75

76 77 78

79

Boc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

53C

-160

b.

Gra

niti

c ro

ck

incl

usio

n in

qu

artz

m

onzo

nite

of

th

e B

ould

er b

atho

lith

, M

onta

na.

R.

W.

Cha

pman

. G

rano

dior

ite

____

____

____

____

G-1

55.

Sno

qual

mie

ba

thol

ith,

al

ong

nort

h sl

ope

of G

oat

Isla

nd

Mou

ntai

n,

Mou

nt

Rai

nier

N

atio

nal

Par

k, W

ash.

D

. G

ottf

ried

, W

. L

. S

mit

h.

54-W

-48.

N

orth

si

de

of

Juli

an

Cre

ek,

nort

h c

ente

r se

c. 1

7, T

.38N

., R

.42E

., O

sgoo

d M

ount

ains

qu

adra

ngle

, O

sgoo

d M

oun­

ta

ins.

Nev

. P

. E

. H

otz.

G-2

03.

Pay

mas

ter

min

e,

Cra

ters

of

th

e M

oon

Mon

umen

t, Id

aho,

D

. G

ottf

ried

, W

. L

. S

mit

h.

BC

-1-2

. S

ierr

a S

an

Ped

ro

de

Mar

tir

Mou

ntai

ns,

Baj

a C

alif

or­

nia.

L

. T

. S

ilve

r.

Min

eral

___-

_do_

--_-

____

-__-

_do_

_. _

__ _

____

_do _

___

_.

Mes

h si

ze

-80

+4

00

-80+

200

-80 +

400

-80+

400

-100+

200

a pe

r mg

per h

r

340

144

378

305

3,52

9

Lea

d (p

pm)

Det

erm

inat

ions 15

3.6

10,

11

9.0

165,

170

Mea

n 10.5

168

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

110 62 69 73

99

Cite

d ge

olog

ic a

ge o

f the

ro

ck

No

dat

a.

R.

W.

Cha

pman

.

Ter

tiar

y (

post

- G

uye

form

atio

n) .

Wat

ers,

195

5.

Pre

-Mio

cene

, po

st-

Lat

e P

enns

yl-

vani

an.

P.

E.

Hot

z.

Ter

tiar

y.

Ros

s an

d F

orre

ster

, 19

47.

Ear

ly L

ate

Cre

ta­

ceou

s (p

ost-

Al-

bi

an,

pre-

Mae

s-

tric

htia

n) .

Sil­

ve

r an

d ot

hers

, 19

56.

00 to O § o F o

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 83

o Q

<5 O

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co. C. Fri

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d-al

pha

age

dete

rmin

atio

ns o

f ac

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ory

min

era

ls C

onti

nued

00

No. 87 88

89 90

91

92

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Gra

nite

_ _

___

__

__

____

__

CF

-1.

Isth

mus

of

Teh

uant

epec

are

a,

near

H

uilo

tepe

c (O

axac

a)

IVIe

xico

. C

. F

ries

, jr

., B

. W

ebbe

r.

Gra

nite

___

____

__

____

____

_

JAL

-1.

Fou

r m

iles

sout

heas

t of

Jal

apa

(Oax

aca)

Mex

ico.

C

. F

ries

, Jr

., B

. W

ebbe

r.

Ton

alit

e__

____

__

____

__

_ _

G-1

0.

Sou

ther

n C

alif

orni

a ba

thol

ith,

A

guan

ga,

Cal

if.

E.

S. L

arse

n, J

r.

Gre

en V

alle

y to

nali

te_

____

___

G-l

l.S

outh

ern

Cal

ifor

nia

bath

olit

h,

Gre

en V

alle

y, C

alif

. E

. S.

Lar

sen,

Jr.

, D

. G

ottf

ried

. G

reen

Val

ley

tona

lite

_

____

SL

R-1

38.

Sou

ther

n C

alif

orni

a ba

thol

ith,

G

reen

Val

ley,

Cal

if.

E.

S. L

arse

n, J

r.

Tonal

ite.

___

___

__

____

__

_G

-30.

S

outh

ern

Cal

ifor

nia

bath

olit

h,

sout

hwes

t of

Pal

m S

prin

gs,

Cal

if.

E.

S. L

arse

n, J

r.,

D.

Got

tfri

ed.

Min

eral

__

__

.do

-__

__

__

_

_.__

_do __ _

____

___-

_do_

--_-

__

-_._

_do_

-_-_

____

-_._

_do _

_-_

-_.

Mes

h siz

e

-80

+2

00

-80

+2

00

-100+

200

-100 +

200

-100 +

200

-10

0 +

200

a pe

r m

g pe

r hr 310

104

280

149

340

317

Lea

d (p

pm)

Det

erm

inat

ions 12

4. 0

, 5.

0

11 6.0

15

14

Mea

n 4.5

Lead

- al

pha

age

in

mill

ions

of

yea

rs 96 108 98 100

110

110

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Pos

t-pr

obab

le P

ale­

oz

oic.

B

. W

eb­

ber,

C.

Fri

es,

Jr.

Do.

Ear

ly

Lat

e C

re­

tace

ous

(pos

t-

Lat

e T

rias

sic,

pr

e-L

ate

Cre

­ ta

ceou

s) .

Lar

- se

n, 1

948.

D

o.

Do.

Do.

§ o F

O

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 85

o O

o O

oP

o Q

o O

Cec

i£cc

C

oc ocC

l> C1-1 crcs

O8+o o

+200 00+200 +2 00+20U 00+2 00 + 200 00+200

00 OJ

506320 5S

Lead

-alp

ha a

ge d

eter

min

atio

ns o

f acc

esso

ry m

iner

als

Con

tinu

ed

No.

101

102

103

104

105

106

Roc

k ty

pe

i ie

ld N

o.

Loc

ality

C

olle

ctor

Mou

nt H

ole

gran

odio

rite

- ___

_Z

-17.

S

outh

ern

Cal

ifor

nia

bath

olit

h,

Mou

nt H

ole,

Cal

if.

E.

S. L

arse

n, J

r.

Sto

new

all

gran

odio

rite

_ _

____

G-4

8.

Sou

ther

n C

alif

orni

a ba

thol

ith,

S

tone

wal

l M

ount

ain,

Cal

if.

E.

S. L

arse

n, J

r.

Woo

dson

Mou

ntai

n gr

anod

iori

te

S-6

. S

outh

ern

Cal

ifor

nia

bath

olit

h,

nort

heas

t of

Des

cans

o Ju

nc­

tion

, C

alif

. E

. S.

Lar

sen,

Jr.

W

oods

on M

ount

ain

gran

odio

­ ri

te.

Z-1

6.

Sou

ther

n C

alif

orni

a ba

thol

ith,

D

esca

nso

Junc

tion

, C

alif

. E

. S.

Lar

sen,

Jr.

W

oods

on M

ount

ain

gran

odio

­ ri

te.

G-3

2A.

Sou

ther

n C

alif

orni

a ba

thol

ith,

w

est

of E

lsin

ore,

Cal

if.

E.

S. L

arse

n, J

r.

Woo

dson

Mou

ntai

n gr

anod

io­

rite

. S

-2.

Min

eral

Zir

con.

___

____

_

____

_do_

_-_-

--_-

____

_do _

_-.

-_-

Zir

con.

___

____

_

Xen

otim

e___

__.

____

_do ..

......

Mes

h siz

e

-100+

200

-10

0+

20

0

-100+

200

-100+

200

-100+

200

-100+

200

-100+

200

-100+

200

aper

mg

per

hr

1,2

04

545

1,18

0

6,43

0

1,23

5

6,40

0

457

433

Lea

d (p

pm)

Det

erm

inat

ions 46 21 46

360 50

260 22

20,2

2

Mea

n 21

Lead

- al

pha

age

in

mill

ions

of

yea

rs 95 96 97

117

10^

104

120

12.7

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Ear

ly L

ate

Cre

­ ta

ceou

s (p

ost-

L

ate

Tri

assi

c,

pre-

Lat

e C

re­

tace

ous)

. L

ar­

sen,

194

8.

Do.

Do.

Do.

Do.

Do.

Do.

00

O5

Sou

ther

n C

alif

orni

a ba

thol

ith,

1

mile

sou

th

of

Tem

ecul

a,

Cal

if.

E.

S.

Lar

son,

Jr.

107

Gra

nit

e_

____________.

Z-1

5.S

outh

ern

Cal

ifor

nia

bath

olit

h,

Rub

idou

x M

ount

ain,

C

alif

. E

. S.

Lar

sen,

Jr.

108

Gra

nit

e___________.

EL

-167

.S

outh

ern

Cah

'forn

ia b

atho

lith

, R

ubid

oux

Mou

ntai

n, C

alif

. E

. S.

Lar

sen,

Jr.

109

Rat

tles

nake

gra

nit

e___._

___..

X-1

01.

Sou

ther

n C

alif

orni

a ba

thol

ith,

C

uyum

aca

quad

rang

le, C

ali­

fo

rnia

. E

. S.

Lar

sen,

Jr.

110

Gra

nodi

orit

e_ _

____

____

____

__R

CE

-54-

7-28

A.

Pom

ona

Til

e qu

arry

, M

ojav

eD

eser

t ar

ea,

Cal

ifor

nia.

R

. C

. E

llis

.11

1 G

rani

te__

____

____

____

_ .

RC

E-5

4-7

-14

B.

Nee

iiac

h qu

adra

ngle

, M

ojav

eD

eser

t ar

ea,

Cal

ifor

nia.

R

. C

. E

llis

.11

2 Q

uart

z m

onzo

nit

e______-_

_.

G-2

1.S

outh

ern

Cal

ifor

nia

bath

olit

h,

Pro

vide

nce

Mou

ntai

n, C

alif

. E

. S.

Lar

sen,

Jr.

113

Qua

rtz

monzo

nit

e_._

______.

G-2

4M.

Sou

ther

n C

alif

orni

a ba

thol

ith,

Sod

a L

ake,

Cal

if.

E.

S. L

arse

n, J

r.

Zir

con

(met

a-

mic

t).

Zir

con.

Xen

otim

e.

Zir

con.

.do.

.do.

Zir

con

(met

a-

mic

t).

-100+

200

-100+

200

-100+

200

-80 +

200

-80+

200

-100 +

200

-100+

200

2,70

0

725

1,74

3

237

866

610

4,6

60

106 29 80

& 0

, 9.

0

30,3

2 23 180

8.5

31

98 99 117 89 89 94 96

Do.

Do.

Ear

ly L

ate

Cre

­ ta

ceou

s (p

ost-

L

ate

Tri

assi

c,

pre-

Lat

e C

re­

tace

ous)

. E

ver

- h

art,

195

1.M

esoz

oic.

M

ille

r,

1946

.

Do.

Do.

Do.

00

Lead

-alp

ha a

ge d

eter

min

atio

ns o

f acc

esso

ry m

iner

als

Con

tinu

ed

No.

114

115

116

117

118

119

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Qua

rtz

mon

zoni

te _

___

____

__R

CE

-54-

7-14

C.

Ros

amon

d qu

adra

ngle

, M

o-

jave

Des

ert

area

, C

alif

orni

a.

R.

C. E

llis

.

RC

E-5

4-7-

18A

. Iv

anpah

qu

adra

ngle

, M

ojav

e D

eser

t ar

ea,

Cal

ifor

nia.

R

. C

. E

llis

.

RC

E-5

4-7-

27C

. W

hite

tan

ks,

sout

h of

Tw

enty

N

ine

Pal

ms,

Moj

ave

Des

ert

area

, C

alif

orni

a.

R.

C.

Ell

is.

Gra

nite

_ _

___

____

__ _

RC

E-5

4-7-

28B

. G

rani

te M

ount

ains

, so

uthe

ast

of

App

le

Val

ley,

M

ojav

e D

eser

t ar

ea,

Cal

ifor

nia.

R

. C

. E

llis

. 8uar

tz m

onzo

nite

___

____

____

_-2

8.

Sou

ther

n C

alif

orni

a ba

thol

ith,

B

erdo

o C

anyo

n, C

alif

. E

. S.

Lar

sen,

Jr.

G-1

5.S

outh

ern

Cal

ifor

nia

bath

olit

h,

Cot

tonw

ood

Spr

ings

, C

alif

. E

. S.

Lar

sen,

Jr.

Min

eral

Zir

con.

___

_ __

_

__--

_do_

-___

_-_-

__--

_do___--

-_-

_-_

-_d

o_

--~

.-_-

-_._

_do.-

--_--

__

__

_._

do

_--

~-_

_

Mes

h si

ze

-80

+2

00

-80

+2

00

-80

+2

00

-80

+2

00

-100+

200

-100+

200

a pe

r m

g pe

rhr

203

171

267

590

385

190

Lea

d (p

pm)

Det

erm

inat

ions

8. 0

, 8.

0

& 0

, 7.

0

12,1

3

27,

281

20

10

Mea

n 8.0

7. 5

12.5

27.

5

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears 98

109

116

116

129

131

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Mes

ozoi

c. M

ille

r,

1946

.

Do.

Do.

Do.

Do.

Do.

00

00 o § F

O

O

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 89

PS *

"Si O5

! §0«

op o Q Q

CO CO 05 CO

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CO

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Lead

-alp

ha a

ge d

eter

min

atio

ns o

f acc

esso

ry m

iner

als

Co

nti

nu

ed

No.

126

127

128

129

130

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Gra

nodi

orit

e . _

____

____

___ _

PB

-7.

Big

P

ine

quad

rang

le,

sout

h­

east

co

rner

se

c.

33,

T.9

S.,

R.3

3E.,

one-

four

th

mile

so

uth

of

Thi

rd

Lak

e,

near

B

isho

p, C

alif

. P

. C

. B

atem

an.

Gra

nodi

orit

e--

____

____

_ _

__P

B-5

. B

ig

Pin

e qu

adra

ngle

, N

WJ^

se

c. 1

4, T

.10S

., R

.33E

., ne

ar

Bis

hop,

Cal

if.

P.

C.

Bat

eman

. Q

uart

z m

onzo

nite

_ _

____

____

PB

-2.

Mou

nt T

om q

uadr

angl

e, w

est

of

surf

ace

wor

king

s P

ine

Cre

ek

min

e,

near

B

isho

p,

Cal

if.

P.

C.

Bat

eman

. Q

uart

z m

onzo

nite

_ _

__

_ _

_54-E

M-l

. H

unte

r M

ount

ain

bath

olit

h,

sout

hwes

t co

rner

U

behe

be

quad

rang

le,

Inyo

C

ount

y,

Cal

if.

E.

M.

Mac

Kev

ett.

Is

abel

la g

rano

dior

ite

____

____

_E

MM

-1.

Ker

n R

iver

ur

aniu

m

area

, C

alif

orni

a.

E.

M.

Mac

Kev

ett.

Min

eral

Zir

con _ _ _

___

_

_d

o_

___

_ __ d

o _

_ _

_ _

_

_d

o_

-_-_

-__

_____do -

__ _

Mes

h siz

e

-100+

200

-100+

200

-100+

200

-80 +

200

-80+

200

-200+

400

-40

0

a pe

r m

g pe

rhr

221

331

796

145

283

320

351

Lead

(pp

m)

Det

erm

inat

ions 10

15,

16

37 6.0

9. 0

, 10

11

, 12

13

,14

Mea

n

15.5

9.5

11

.5

13.5

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

112

116

116

103

83

89

96

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Lat

e Ju

rass

ic.

Hin

ds,

1934

.

Do.

Do.

Do.

Do.

131

132

133

134

Hal

f D

ome

quar

tz m

onzo

nite

.53

-PB

-10.

Mou

nt

Lye

ll qu

adra

ngle

, N

WJ£

sec

. 28

, T

.1S

., R

.23E

., 1

mile

sou

thw

est

of T

enay

a L

ake,

Y

osem

ite

Nat

iona

l P

ark,

Cal

if.

P.

C.

Bat

eman

.E

l C

apit

an g

rani

te._

____

____

_53

-PB

-9.

Yos

emit

e qu

adra

ngle

at

junc

­ ti

on o

f T

amar

ack

and

Cas

­ ca

de C

reek

s, s

ec,

25,

T.2

S.,

R.2

0E.,

Yos

emit

e N

atio

nal

Par

k,

Cal

if.

P.

C.

Bat

eman

.G

rano

dior

ite.

___

-._-

___-

_-._

_-53-P

B-8

.Y

osem

ite

quad

rang

le,

at j

unc­

ti

on o

f Ava

lanc

he C

reek

wit

h M

erce

d R

iver

, N

WJ^

se

c.

14,

T.3

S.,

R.2

0E.,

Yos

emit

e N

atio

nal

Par

k, C

alif

.P

. C

. B

atem

an.

Qua

rtz

dior

ite-

____

____

____

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D-1

80-3

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est-

cent

ral

par

t of

F

renc

h G

ulch

qua

dran

gle,

1.3

mil

es

east

fr

om

Buc

khor

n S

um­

mit

, U

.S.

Hig

hway

29

9,

Sha

sta

Bal

ly

bath

oHth

, K

lam

ath

Mou

ntai

ns,

Sha

sta

Cou

nty,

Cal

if.

J. F

. R

ober

tson

.

Tho

rite

.

Zir

con

_.

.do.

.do.

-do.

100

+20

0

100+

200

-100+

200

-100+

200

-100+

200

10, 3

70 330

395

385

276

454

15,1

6 15

15.5

88 117 94

Do.

Do.

1610

5D

o.

9.0

81D

o.

GO

CO

Lea

d-al

pha

age

dete

rmin

atio

ns o

f ac

cess

ory

min

era

ls C

onti

nued

No.

135

136

137

138

139

Roc

k ty

pe

Fie

ld N

o.

Loc

ality

C

olle

ctor

Bio

tite

-hor

n bl

ende

qua

rtz

dio-

ri

te.

MD

-180

-4.

Sou

thea

st

par

t of

F

renc

h G

ulch

qu

adra

ngle

, w

here

S

ilve

r Fal

ls m

ine

road

cro

sses

A

ndre

ws

Cre

ek, S

hast

a B

ally

ba

thol

ith,

K

lam

ath

Mou

n­

tain

s, S

hast

a C

ount

y, C

alif

. J.

F.

Rob

erts

on.

Ta-

1.

Fac

ies

of t

he B

ald

Mou

ntai

n ba

thol

ith,

S

umpt

er

quad

­ ra

ngle

, B

aker

Cou

nty,

Ore

g.

W.

Tau

bene

ck.

FG

W-1

2-53

. G

rous

e C

reek

, M

edfo

rd

quad

rang

le, J

acks

on C

ount

y,

Ore

g.

F.

G.

Wel

ls.

Gra

nodi

orit

e __

____

_ __

_

FG

W-3

-54.

M

edfo

rd q

uadr

angl

e, J

acks

on

Cou

ntv,

Ore

g.

F.

G.

Wel

ls.

Bio

tite

- h

ornb

lend

e - p

yrox

ene

dior

ite.

C

PR

-119

. D

iana

sch

ool,

Qua

rtzb

urg

dis­

tr

ict,

Ida

ho.

B.

F.

Leo

nard

, C

. P

. R

oss.

Min

eral

Zir

con _ _

____

__

____

_do_

__--

___-

-_.-

_do___--

__

_-

Zir

con

(and

in­

clud

ed a

pa­

tite

).

-___

do__

_

Mes

h si

ze

-100+

200

-80

+2

00

-80 +

400

-80+

400

-80 +

200

-2

00+

400

a pe

r m

g pe

r hr 19

7 22

3

153

230

322

291

100

116

Lead

(ppm

)

Det

erm

inat

ions 8 11

5. 5

, 7.

0

9. 0

, 10

59,5

9

12,

13

3. 0

, 4.

0, 4

. 0

4. 0

, 5.

0

Mea

n 6.3

9. 5

59 12.5

3.7

4

.5

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

10-

123

102

103

425

107 92

96

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Lat

e Ju

rais

sic.

H

inds

, 19

34.

Lat

e Ju

rass

ic

or

Ear

ly

Cre

tace

­ ou

s.

Tau

be­

neck

, 19

55.

Jura

ssic

or

Cre

tace

­ ou

s.

Wel

ls,

1956

.

Do.

Ter

tiar

y.

Ros

s an

d F

orre

ster

, 19

47.

Lar

amid

e.

And

erso

n, 1

952.

co fcO

OR

140

141

142

143

144

145

Qua

rtz

dior

ite__

____

__ _

____

L-1

13.

Idah

o ba

thol

ith,

Sal

mon

Riv

er

belo

w S

tanl

ey,

Idah

o.

E.

S. L

arse

n, J

r.

Qua

rtz

dior

ite__

___ _____ _

L-2

17.

Idah

o ba

thol

ith,

nea

r B

unga

­ lo

w,

Idah

o.

E.

S. L

arse

n, J

r.

L-8

1.

Idah

o ba

thol

ith,

S

outh

F

ork

Pay

ette

Riv

er,

Idah

o.

E.

S. L

arse

n, J

r.

L-7

0.

Idah

o ba

thol

ith,

nea

r C

asca

de,

Idah

o.

E.

S. L

arse

n, J

r.

Por

phyr

itic

bi

otit

e gr

anod

i-or

ite.

L-5

3-57

3a.

Idah

o ba

thol

ith,

2,

000

feet

nort

h-no

rthw

est

of

Pea

k 85

20 n

ear

Pilo

t P

eak

trai

l, B

ig

Cre

ek

quad

rang

le,

Idah

o.

B.

F.

Leo

nard

. P

orph

yrit

ic

biot

ite-

mus

covi

tegr

anod

iori

te.

L-5

3-88

. N

ear

Big

Cre

ek R

ange

r S

ta­

tion

, Id

aho

bath

olit

h,

Big

C

reek

qua

dran

gle,

Ida

ho.

B.

F.

Leo

nard

.

___ d

o __

____

___

Tho

rite

_____

___ d

o _

__

__

-100+

200

-100+

200

-100+

200

-10

0+

20

0

-10

0+

20

0

-80

+2

00

-80

+2

00

80

4-9

0O

825

1,37

5

225

370

210

340

2,72

6

2fi

7R

30 70

9. 0

, 10 16 9.0

13,1

5

144,

148 145

9.5

14 146

90 102

105

107

107

102

113

Cre

tace

ous.

R

oss

and

For

rest

er,

1947

.

Do.

Do.

Do.

Do.

Do.

Lead

-alp

ha a

ge d

eter

min

atio

ns o

f acc

esso

ry m

iner

als

Con

tinu

ed

No.

146

147

148

149

150

151

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Hor

nble

nde-

biot

ite

dior

ite

____

_L

-53-

377

Hal

f a

mile

so

uthw

est

of

Mah

an

cabi

n,

nort

hwes

t re

ctan

gle

Big

C

reek

qu

ad­

rang

le,

Idah

o.

B.

F.

Leo

nard

. B

ioti

te-h

ornb

lend

e di

orit

e __

_C

PR

-118

. B

orde

r fa

cies

of

Idah

o ba

tho­

li

th,

Hor

sesh

oe B

end,

Ida

ho.

C.

P.

Ros

s, B

. F

. L

eona

rd.

Bio

tite

-aug

ite-

hype

rsth

ene

di­

orit

e.

CP

R-1

17.

Bor

der

faci

es,

Idah

o ba

tho­

li

th,

Hai

ley,

Ida

ho.

C.

P.

Ros

s, B

. F

. L

eona

rd.

G-2

00.

Idah

o ba

thol

ith,

nea

r S

tanl

ey,

Idah

o.

D.

Got

tfri

ed.

L-1

10.

Idah

o ba

thol

ith,

be

low

Sta

n­

ley,

Ida

ho.

E.

S. L

arse

n, J

r.

Gra

nodi

orit

e.__

_ _

__

L-2

88.

Idah

o ba

thol

ith,

nea

r A

tlan

ta,

Idah

o.

E.

S. L

arse

n, J

r.

Min

eral

Zir

con_

_ __

____

_

. _

do _

_

Mes

h siz

e

-80 +

200

-80

+2

00

-80 +

200

-10

0+

20

0

-100+

200

-10

0+

20

0

aper

mg

per

hr 158

120

173

190

1,00

0

700

Lea

d (p

pm)

Det

erm

inat

ions

28,

32,

33

5. 0

, 6. 0

8.0

,8.0 10

38

38

Mea

n

31

5.5

8.0

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

475

114

115

13. 94

IBS

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Cre

tace

ous.

Ros

s an

d F

orre

ster

. 19

47.

Cre

tace

ous.

C

. P

. R

oss.

L

aram

ide.

A

nder

son,

195

2.

Cre

tace

ous.

U

mpl

eby,

W

estg

ate,

and

R

oss,

193

0.

Lar

amid

e.

And

erso

n, 1

952.

C

reta

ceou

s.

Ros

s an

d F

orre

ster

, 19

47.

Do.

Do.

ht--

H

OR

152

153

154

155

156

157

158

159

Qua

rtz

mon

zoni

te _

___

.__.

__L

-207

. Id

aho

bath

olit

h. I

ndia

n G

rave

ne

ar P

owel

l, Id

aho.

E

. S.

Lar

sen,

Jr.

G

rani

te _

_ . ._

_G

-199

.

nort

heas

t of

Gar

den

Val

ley,

Idah

o.

D.

Got

tfri

ed.

M-6

0.

Idah

o ba

thol

ith,

nea

r P

lace

r-

ville

, Id

aho.

E

. S.

Lar

sen,

Jr.

L-2

64.

Idah

o ba

thol

ith

area

ne

ar

Idah

o C

ity,

Ida

ho.

E.

S. L

arse

n, J

r.

L-2

69.

Idah

o ba

thol

ith

area

, ne

ar

Idah

o C

ity,

Ida

ho.

E.

S. L

arse

n, J

r.

Mus

covi

te p

lace

r. _

_._

._.

L-2

67.

Idah

o ba

thol

ith

area

ne

ar

Idah

o C

ity,

Ida

ho.

E.

S, L

arse

n, J

r.

0-7.

Id

aho

bath

olit

h,

near

Id

aho

Cit

y, I

daho

. E

. S.

Lar

sen,

Jr.

G

ran

odio

rite

___.-

_-_

-. _

_H

CD

-63.

G

em

stoc

ks,

Coe

ur

d'A

lene

di

stri

ct,

Idah

o.

A.

B.

Gri

ggs.

___ d

o..

....

...

_._

_.d

o-_

Xenoti

me......

Mon

azite

_ _

_._

___..do_. ..

._

. ....d

o... .

.....

_

do_.

...

.

.....d

o..... _

_

Zir

con.

... _

_

-100+

200

-100+

200

-100+

200

-100+

200

-100+

200

-100+

200

-100+

200

-100+

200

-100+

200

-100+

200

922

1,97

0

5,61

76,

025

2,98

3

2,99

4

2,88

8

2,63

4

3,24

1

292

37 90

250,

256 220

150

150

155

160

155 11

253

100

114 93 93 105

104

112

127

100 94

Do.

Do.

i (

Do.

i t

Do.

!

Do.

! i i 4 {

Do,

> i ! i i

Do.

| i i

Cre

tace

ous

or e

arly

j

Ter

tiar

y.

! A

. B

. G

rigg

s.

' < c

Lead

-alp

ha a

ge d

eter

min

atio

ns o

f acc

esso

ry m

iner

als

Con

tinu

ed

No.

160

161

162

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Gra

nodi

orit

e. _

____

____

____

__H

CD

-62.

Gem

st

ocks

, C

oeur

d'

Ale

nedi

stri

ct,

Idah

o.A

. B

. G

rigg

s.R

are-

met

al d

epos

its

of m

ona-

zite

, ni

obiu

m-b

eari

ng

il-

men

ite

segr

egat

ed

in

lim

e­st

one

laye

rs i

n P

reca

mbr

ian

met

ased

imen

tary

te

rran

ene

ar

bord

er

zone

of

Id

aho

bath

olit

h.ID

-9-3

0.

Indi

an

Cre

ek

area

, M

iner

alH

ill

dist

rict

, L

emhi

Cou

nty,

Idah

o.E

. P

. K

aise

r.R

are-

met

al d

epos

its

of m

ona-

zite

, ni

obiu

m-b

eari

ng

il-

men

ite

segr

egat

ed

in

lim

e­st

one

laye

rs i

n P

reca

mbr

ian

met

ased

imen

tary

te

rran

ene

ar

bord

er

zone

of

Id

aho

bath

olit

h.ID

-9-3

5.

Indi

an

Cre

ek

area

, M

iner

alH

ill

dist

rict

, Ij

emhi

Cou

nty,

Idah

o.E

. P

. K

aise

r.

Min

eral

Zir

con

and

thor

ite.

Mon

azit

e»._

.

do

Mes

h siz

e

-100+

200

+ 6

0

+ 6

0

a pe

r in

g pe

r hr

1,7

39

578

1,02

4

Lead

(pp

m)

Det

erm

inat

ions

100

25,3

0

45

,48

Mea

n

27.5

46.5

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

lie 99 95

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Cre

tace

ous

or e

arly

Ter

tiar

y.

A.

B.

Gri

ggs.

Cre

tace

ous.

E

. P

.K

aise

r.

Do.

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 97

*ho S fr o a A-S o ot5s~ sa>_^»ci >H I'S rf

o P

oft

c5p

op A.

"5

c> CJ

(Nr-(

cT

COeo

(0 t~oo

sI

Oo<N

o00

-a

1 OQ

era!.'

03S*S «

-S^S^MS^SI^UI^

KM WP* Opq QOOo

6.

Halford, Sultan quad-

gle, Washington.

oried, W. L. Smith.

g «g'Bb . * S ^|l i13 £w 0* .4

t|l .£ a « «2r% O-f

1°|3 ^il^ IllllS«N g'43 2"o:§?»

'HOO P

Lead

-alp

ha a

ge d

eter

min

atio

ns o

f acc

esso

ry m

iner

als

Conti

nued

No.

IRQ

.toy

170

171

172

173

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

To

nal

ite.

.. _

________

HC

-2.

Che

lan

bat

ho

lith

, L

ower

Kna

pp

Cou

lee

(eas

t si

de),

Che

lan

quad

rang

le,

Was

h­in

gton

.C

. A

. H

opso

n.G

neis

sic

ho

rnb

len

de-

qu

artz

dior

ite.

FW

-60-

55.

Che

lan

bath

olit

h,

Hol

den

quad

rang

le,

nort

h si

deE

ntia

t R

iver

, 3

mile

s so

uth

of H

olde

n, W

ash.

F.

W.

Cat

er.

Gra

nodi

orite

____

.

DF

C-1

06-

55.

Hol

den

quad

rang

le,

Was

hing

­to

n.D

. F

. C

row

der.

Ton

alit

e. _

____

___ _

HC

-1.

Che

lan

bat

holi

th,

Upper

K

napp

C

oule

e (w

est

side

),C

hela

n qu

adra

ngle

, W

ash­

ingt

on.

C.

A.

Hop

son.

Ton

alit

e.__

___ _ _

_ _

DF

C-1

07-5

5.H

olde

n qu

adra

ngle

, W

ash­

ingt

on.

D.

F.

Cro

wde

r.

Min

eral

Zir

con _

. ___

. .d

o.........

. _ .d

o _____

_. ..

.do... .

....

.

. _ .d

o..

....

_

Mes

h si

ze

-80+

200

-80+

200

-80

+2

00

-80+

200

-80

+2

00

aper

mg

per h

r no

yo 78 110 83 56

Lea

d (p

pm)

Det

erm

inat

ions

4. 0

, 4. 2

3. 2

, 3. 5

5. 4

, 4. 4

40

41

^C*

Vf

^C*

-L

2. 5

, 3. 2

Mea

n 41 X

3.35

4.9

4.05

2.85

Lea

d,

alph

a ag

e in

m

illio

ns

of y

ears 104

107

in 121

126

Cite

d ge

olog

ic a

ge o

f the

ro

ok

Pre

-Pal

eoce

ne,

post

-ear

lyM

esoz

oic.

Wat

ers,

193

8.

Do.

Do.

Do.

Do.

CO

0

0 1

174

175

176

177

178

179

Qua

rtz

dior

ite_

____

____

____

FC

-1.

Hol

den

quad

rang

le,

Was

hing

­ to

n.F.

W.

Cat

er.

Gra

nodi

orite

_ __

____

____

____

_G

-122

.Si

milk

amee

n ba

thol

ith,

2 m

iles

from

B

icht

er

Ran

ch,

near

W

ashi

ngto

n-B

riti

sh C

olum

­ bi

a bo

rder

, B

riti

sh C

olum

­ bi

a, C

anad

a.D

. G

ottf

ried

, W

. L

. S

mit

h.G

rano

dior

ite_

____

____

____

___

RE

F-1

.N

elso

n ba

thol

ith,

Low

er A

rrow

L

ake

dist

rict

, B

riti

sh

Co­

lu

mbi

a, C

anad

a.R

. A

. Fo

Lins

bee.

Leu

cosy

enit

e. _

____

____

____

__38

81.

Nea

r M

ount

F

airp

lay,

m

ile-

post

29,

For

tym

ile

dist

rict

, ea

st-c

entr

al A

lask

a.A

. N

elso

n, J

. J.

Mat

zko.

Gra

nodi

orit

e___

____

____

____

54-A

Pr-

106.

Tak

u In

let,

near

ou

tlet

of

Tur

ner

Lak

e, w

est o

f Jun

eau,

sout

heas

tern

Ala

ska.

G

. P

lafk

er.

Dio

rite

__._

____

____

____

____

_55

-ASn

-242

.T

olst

oi P

oint

, P

rinc

e of

Wal

es

Isla

nd

, n

ort

hea

st-c

entr

al

part

of

C

raig

qu

adra

ngle

, so

uthe

aste

rn A

lask

a.C

. S.

Sai

nsbu

ry.

.do.

.do.

.do.

.do.

Zir

con

(met

amic

t).

Zir

con.

.do.

-100+

200

-80

+2

00

-100+

200

-60

+2

00

-200+

400

-100

74 160

310

1,270

1, 134

1,47

61,550

1,62

01,

930

1,594

2,600

152

142

4.0

7. 2

, 7.

5

13,1

4

48,52 45 63

60,63 68 72 72 115

5. 8

, 5.

6

5. 8

, 6. 0

7.35

13.5

50 61. 5

5.7

5.9

134

114

108 98 99 100 99 104 93 11£?

110 93 103

Do.

Do.

Lat

e C

reta

ceou

s or

yo

unge

r.

Sm

ith

and

Ste

vens

on,

1955

.

Mes

ozoi

c.

Mer

tie,

19

37.

Lat

e E

arly

C

reta

­ ce

ous

or L

ate

Ju­

rass

ic (?

). B

ud-

ding

ton

and

Cha

- pi

n, 1

929.

Do.

1 § on CO

C

O

Lead

-alp

ha a

ge d

eter

min

atio

ns o

f acc

esso

ry m

iner

als

Con

tinu

ed

No.

180

181

182

183

184

185

186

Boc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

13-A

. P

orcu

pine

C

reek

, K

usku

lana

R

iver

are

a,

Chi

tina

Val

ley,

ea

st-c

entr

al A

lask

a.

J. F

. S

eitz

. G

rani

te p

orp

hyry

...-

.---

----

SC

C-1

. N

ear

San

Man

uel,

Ari

z.

S. C

. C

reas

ey.

Peg

mat

itic

fac

ies

of n

ephe

line

sy

enit

e.

56-2

. L

arvi

kofj

orde

n, N

orw

ay.

T.

F.

W.

Ear

th.

Peg

mat

itic

nep

heli

ne s

yen

ite.

. 56

-3.

Tve

itda

len,

Nor

way

. T

. F

. W

. E

arth

.

TB

-7.

Bar

kevi

k,

Lan

gesu

ndsf

jord

, so

uthe

rn N

orw

ay.

T.

F.

W.

Ear

th.

56-8

. L

aven

Lan

gesu

ndsf

jord

, so

uth­

er

n N

orw

ay.

T.

F.

W.

Ear

th.

Cat

acla

stic

met

anor

ite _ .

N-l

. D

jupd

alen

, L

osby

, L

oren

skog

H

erad

, A

kers

hus,

so

uthe

rn

Nor

way

. H

. F

aul,

0.

Hol

teda

hl.

Min

eral

Zir

con.

... ..

.

__

_ d

o __

___

....

.do..

. ___ .

....

.do..

. ___

....

.do..

. ___ .

....

.do..

. ___

Mes

h siz

e

-80+

400

-80+

400

+ 2

0

+20

+20

+ 2

0

-100+

200

aper

mg

per h

r

283 73 177 76

75 324

108

Lead

(pp

m)

Det

erm

inat

ions

11,1

3

3. 0

, 3.

5, 4

. 0

9.0

,11

4. 9

, 4.

9

5. 0

, 5. 0

, 5.

0,

5.0

20,2

5

7. 0

, 8. 0

, 9. 0

Mea

n

12 3.5

10 4.9

5.0

22.5

8.0

Lead

- al

pha

age

in

mill

ions

of

yea

rs

105

115

140

160

160

173

184

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Lat

e E

arly

C

reta

­ ce

ous

or L

ate

Ju­

rass

ic (?

).

Bud

- di

ngto

n an

d C

ho­

pin,

192

9.

Lat

e C

reta

ceou

s or

ea

rly

Ter

tiary

. S.

C.

Cre

asey

.

Ear

ly P

erm

ian.

H

oegh

, 19

36.

Do.

Do.

Do.

No

data

. H

. Fa

ul.

o

o

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 101

9'£'S O*fita) j3 PH W> 0>>8 fl1«

W

^» ®

I*8' & P

Carboniferous (?) (pre-Santa

Rosa forma­ tion). C.

Fries, Jr.

si **I10|gj

H

Pre-Permian.

Bramkamp an<

others, 1956.

$

usCO 00

o00

CO

CJ

USOCO

COo»CO 00

eo"

c G

-d"

o PI a

ik, Langesundsf;

s^ay. r . Earth,

ine s venite- .--.

c c

-sSO

**?18If « rfi

' -cT . ^< ^^

0 d

o ®'s 1

;, Bedil, 2nd Divi i Sarawak, British

3 in Borneo.

Eloe.

c-c

+» CQ

8-S>S ES o

u, 2nd Division, ivak, British Terrii

>rneo. Roe.

CT:

S3'a* &3s X>

1 ^ ,O psj _-2

ol tl e M o* 1^ 5

i"S

§1 .ga

^ bD

*«> 05 _J ^ 42ls-i 1 4 §11 ; l

"C * * o31 Is! i 51~ 'S -ja «SAt J-:§|^^w.

§^1^^121^.' 5 Wtf^^O

506S20 59 6

Lead

-alp

ha a

ge d

eter

min

atio

ns o

f acc

esso

ry m

iner

als

Con

tinu

ed

No.

194

195

196

197

198

199

200

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Coa

rse

gray

por

phyr

itic

gra

n­

ite.

S

A-2

. E

aste

rn s

ide

of e

aste

rn b

atho

- li

th,

Sau

dia

Ara

bia.

G

. F

. B

row

n.

Gra

nite

roc

k___

____

____

____

_S

A-3

. Je

bal

Z'a

ba,

Sau

di A

rabi

a.

G.

F.

Bro

wn.

F

ine-

grai

ned

gray

gr

anod

io-

rite

. S

A-4

. T

aif ,

Sau

di A

rabi

a.

G.

F.

Bro

wn.

Sa-

6.

Dha

lm,

Sau

di A

rabi

a.

G.

F.

Bro

wn.

S-4

6.

Ash

away

qu

adra

ngle

, R

hode

Is

land

. W

. L

. S

mit

h.

Nar

rag

anse

tt P

ier

gran

ite

____

_Q

-55-

3.A

shaw

ay

quad

rang

le,

Rho

de

Isla

nd.

A.

W.

Qui

nn.

Wes

terl

y gr

anit

e___

_

Q-5

5-4.

A

shaw

ay

quad

rang

le,

Rho

de

Isla

nd.

A.

W.

Qui

nn.

Min

eral

Zir

con_

.___

____

* -

ClO

do

-

Mon

azit

e _ _

___

Mes

h si

ze

-60

+2

00

-60

+2

00

-60

+4

00

-60

+4

00

-80

+2

00

-80+

200

-80

+2

00

otpe

rmg

per

hr 460

360

483

2,08

3 1,

970

380

410

462

304

300

5,49

4

Lea

d (p

pm)

Det

erm

inat

ions

65,

68,

47, 4

9,

61

302,

305

, 30

7, 3

08

48,

50,

50

62,6

5 62

,65

27,2

9

25,2

6

580,

590

Mea

n

66

.5

48 303

307 49 63.5

6

3.5

28

25.5

585

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

340

323

300

35J

377

314

373

333

225

208

220

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Pre

-Per

mia

n.

Bra

mka

mp

and

ot

hers

, 19

56.

Do.

Do.

Do.

Lat

e or

pos

t-

Pen

nsyl

vani

an.

Qui

nn a

nd

othe

rs,

1957

.

Do.

Do.

M

OB a o s o

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 103

oft oft o

flo-

. go §-<

£

fl

O fi

% fr- (N

sooo

ooooIN**

o oo ooo oooo o oo

oo<N

o oo ooo

a o o&

<%

~ s sa-SISH {23

*rt <pa £g|&I<H

& 11 50

O "

oT o

i 12 * oo.J

O S «Q af 1-1S o3 a>i°lw «w S0 oW o1

.1o .^j(P Tj< £H

^z»0^ f||l^ P i^i^isl^ P iil^llilll^

O"

3

Lead

-alp

ha a

ge d

eter

min

atio

ns o

f acc

esso

ry m

iner

als

Con

tinu

ed

No.

208

209

210

211

212

213

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Q-5

3-39

. T

ower

H

ill

Roa

d,

2,50

0 fe

et

sout

h of

M

oore

sfie

ld

road

, N

arra

gans

ett

Pie

r qu

ad­

rang

le,

Rho

de I

slan

d.

A.

W.

Qui

nn.

Sci

tuat

e gr

anit

e gn

eiss

___ _

__Q

-53-

37.

Geo

rgia

vill

e qu

adra

ngle

, F

or-

num

Pik

e, 1

,200

fee

t so

uth­

ea

st o

f w

est

end

of C

apro

n ro

ad,

Rho

de I

slan

d.

A.

W.

Qui

nn.

One

co g

ran

ite.

... _

____

__53

-S-4

8.

Moo

sup,

Con

n.

W.

L.

Sm

ith.

S

yen

ite.

- ___

____

__

_ _

____

_V

t-S

y-5

6J-

12

. W

hite

Mou

ntai

n pl

uton

ic-v

ol-

cani

c se

ries

, ne

ar s

umm

it o

f M

ount

Asc

utne

y, V

t. H

. W

. Ja

ffe,

J.

B.

Lyo

ns.

Gra

nite

_ _ _ _

____

_ _

____

_V

t-G

r-56J-

13.

Whi

te M

ount

ain

plut

onic

-vol

- ca

nic

seri

es,

belo

w s

umm

it

of M

ount

Asc

utne

y, V

t.

H.

W.

Jaff

e, J

. B

. L

yons

.

NH

-M-5

6J-

17

.

Min

eral

__-_

.do_

____

____

____

_ do

... .

....

_

__._

_do_

__ ...

...

....

.do

. __ ..

..

..._

.do

_. _

....

Mes

h si

ze

-80

+2

00

-80+

200

-80

+2

00

-80+

200

-200+

400

-80

+2

00

-2

00+

400

-80+

200

aper

mg

per h

r

800

352

251

544

166

214

247

373

240

260

Lea

d (p

pm)

Det

erm

inat

ions

100 44

35

63,6

5

11,1

2 17

,20

19,2

2 25

,27

16,1

7 18

,20

Mea

n

64 11.5

18

.5

20.5

26 16

.5

19

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

305

303

337

286

170

211

210

175

171

IBS

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Dev

onia

n.

Qui

nn

and

othe

rs,

1957

.

Do.

No

dat

a.

Mis

siss

ippia

n (?

) .

Bil

ling

s,

1956

. L

ate

Per

mia

n (?

).

Lyo

ns a

nd o

ther

s,

1957

.

Do.

Do.

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 105

o ft

ofl

oft

CO O*Q C50*0 * coCNINNIN

>oco coco

IOco­ co

oocot>- us«o IOCD1O<oooooi

OINCO

CO CO CO

00O3(N

co oo"*O

o«oot>-

oo o oo

o o

oo oo o oCO

Lea

d-al

pha

age

dete

rmin

atio

ns o

f ac

cess

ory

min

erals

Con

tinu

ed

No.

218

219

220

221

222

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Mou

nt O

sceo

la g

rani

te _

____

__33

-BN

H-1

7.W

hite

Mou

ntai

n pl

uton

ic-v

ol-

cani

c se

ries

, M

ount

Cho

cura

qu

adra

ngle

, N

ew

Ham

p­

shir

e.

A.

But

ler.

F

ayal

ite

quar

tz s

yen

ite,

___

___

BN

H-2

0.

Dev

ils

Slid

e ri

ng d

ike,

W

hite

M

ount

ain

plut

onic

-vol

cani

c se

ries

, P

ercy

qu

adra

ngle

, N

ew H

amps

hire

. A

. B

utle

r.

MR

-1.

Sto

ck,

Mon

tere

gian

H

ills

, M

ount

R

oyal

, M

ontr

eal,

Q

uebe

c, C

anad

a.

J. B

. L

yons

. W

inne

pesa

ukee

qua

rtz

dior

ite__

N

H-W

Qd

-56

J-16.

New

Ham

pshi

re p

luto

nic

seri

es,

sout

h of

B

elkn

ap

Poi

nt,

Lak

e W

inne

pesa

ukee

qua

d­

rang

le,

New

Ham

pshi

re.

H.

W.

Jaff

e, J

. B

. L

yons

. K

insm

an q

uart

z m

onzo

nite

___

NH

-LM

-1-5

2.

Min

eral

Zir

con.

___

____

_

Zir

con

Th

:U=

2.1

c=

2,3

85.

Che

vkin

ite

Th

:U=

54

c=

2,0

50

fc=

0.50

X!0

-*

Zir

con

(met

amic

t) .

Zir

con_

____

____

Zir

con

Th:U

=0.4

Mes

h si

ze

-60+

200

-60 +

200

-10

0+

20

0

-80 +

200

-80

+2

00

-2

00+

400

-10

0+

20

0

aper

mg

per

hr 470

723

843

465

443

995

2,32

3

353

391

248

Lea

d (p

pm)

Det

erm

inat

ions 50

68

80 44 42 98

210,

215

38,4

0 45

,47

26,3

0

Mea

n

213 39

46 28

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

259

230

232

220

224

20.

224

269

285

28#

Oite

d ge

olog

ic a

ge o

f the

ro

ck

Mis

siss

ippi

an(?

).

Bil

ling

s, 1

956.

L

ate

Per

mia

n (?

).

Lyo

ns a

nd

othe

rs,

1957

.

Do.

Lat

e P

aleo

zoic

. L

yons

and

oth

ers

1957

.

Lat

e D

evon

ian

(?)

(pos

t-E

arly

D

evon

ian)

. B

illi

ngs,

195

6.

Lyo

ns a

nd

othe

rs,

1957

.

Do.

O

O-

223

224

225

226

New

Ham

phir

e pl

uton

icse

ries

, L

ovew

ell

Mou

ntai

n qu

ad­

rang

le,

New

Ham

pshi

re.

J. B

. L

yons

.

Kin

sman

qua

rts

mon

zoni

te _

NH

-C

2-52

. N

ew H

am

pshi

re p

luto

nic

seri

es,

Car

diga

n qu

adra

ngle

, N

ew

Ham

pshi

re.

J. B

. L

yons

. B

ethl

ehem

gne

iss _

____

____

___

NH

-K-8

-52

-1.

New

Ham

pshi

re p

luto

nic

seri

es,

Rum

ney

quad

rang

le,

New

H

amps

hire

. J.

B.

Lyo

ns.

NH

-S-4

-52-1

. N

ew H

amps

hire

plu

toni

c se

ries

, S

unap

ee

quad

rang

le,

New

H

amps

hire

.J.

B.

Lyo

ns.

Con

cord

gra

nit

e.

____

____

___

NH

-Big

-56-J

-20.

Bin

ary

gran

ite,

N

ew

Ham

p­

shir

e pl

uton

ic s

erie

s, S

wen

son

quar

ry,

Con

cord

, N

.H.

H.

W.

Jafl

fe,

J. B

. L

yons

.

c= 2

,560

k

=1

.74

X1

0-*

Mon

azit

e T

h:U

=33

c= 2

,065

fc

=0.

61X

10-*

__._

_do_

___-

__

Zir

con

Th

:U=

1.4

c=

2,4

55

fc =

1.47

X10

-*

Mon

azit

eT

h:U

=8.5

c=

2,1

80

fc

=0.

87X

10~*

X

enot

ime

Th:U

=54

c= 2

,048

fc

=0.

56X

10~*

. M

onaz

ite _

___

_

100+

200

-100+

200

-10

0+

20

0

-100 +

200

-100 +

200

-100+

200

-80

+2

00

4,35

1

333

246

94

9

2,92

2

4,05

3

5,35

2

640,

800

36,3

8 28 ^n 470

530

825,

835

720 07

830

337

270

277

297

Do.

Do.

Do.

266

320

Do.

fe S § GO

Lead

-alp

ha a

ge d

eter

min

atio

ns o

f acc

esso

ry m

iner

als

Conti

nued

No.

227

228

229

230

231

Boc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Con

cord

gra

nite

. ___

.

NH

-C-4

-52-

1.

Bin

ary

gran

ite,

N

ew H

amp­

sh

ire

plut

onic

ser

ies,

Car

di­

gan

quad

rang

le, N

ew H

amp­

sh

ire.

J.

B.

Lyo

ns.

Peg

mat

ite

in C

onco

rd g

rani

te

NH

-C-5

-52-

E.

New

Ham

pshi

re p

luto

nic

serie

s,

Car

diga

n qu

adra

ngle

, N

ew

Ham

pshi

re.

J. B

. L

yons

.

NH

-Gr-

56-J

-19.

In

Fit

chbu

rg p

luto

n on

U.S

. H

ighw

ay 3

, 4.

2 m

iles

sout

h of

Sun

cook

Riv

er,

Mar

tin,

Su

ncoo

k qu

adra

ngle

, N

ew

Ham

pshi

re.

H.

W.

Jaff

e, J

. B

. L

yons

.

NH

-di-

56-J

-18.

E

xete

r pl

uton

, be

twee

n E

xete

r an

d E

ppin

gj N

.H.

H.

W.

Jaff

e, J

. B

. L

yons

. M

etar

hyol

ite_ __ __

NH

-L-1

-56.

Lit

tlet

on f

orm

atio

n, L

ittl

eton

, N

.H.

J. B

. L

yons

.

Min

eral

Mon

azit

e T

h:U

=4

6

c= 2

,052

fc

=0.

58X

10-*

.

Zir

con

____

____

__

_ d

o ___

__

_

____

_do_

____

_

Mes

h si

ze

-100+

200

-100+

200

-80

+2

00

-80+

200

-80+

200

a pe

r in

g pe

rhr

2,7

84

5,28

5

394 75

53

Lea

d (p

pm)

Det

erm

inat

ions

450

700

45,4

8

9. 0

, 10

6. 0

, 7. 0

Mea

n

46

.5 9.5

6.5

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

320

274

286

307

295

Cite

d ge

olog

ic ag

e of t

he

rock

Lat

e D

evon

ian(

?)

(pos

t-E

arly

D

e­

voni

an).

Bill

ings

, 19

56.

Lyo

ns a

nd

othe

rs,

1957

.

Do*

Do.

Do.

Ear

ly t

o M

iddl

e D

evon

ian

(Ori

s-

kany

-Ono

ndag

a ag

e).

J. B

. L

yons

.

o

oo o 1

232

233

234

235

236

237

238

Fels

ic v

olca

nics

,___

____

____

__N

H-M

o-3-

56.

Hig

h gr

ade

zone

of

Lit

tlet

on

form

atio

n,

east

of

L

isbo

n,

N.H

.J.

B.

Lyo

ns.

Gra

nit

e_______._

______..

..N

H-M

W-4

-52-

1.O

liver

ian

plu

tonic

se

ries

, M

ount

W

ashi

ngto

n qu

ad­

rang

le,

New

Ham

pshi

re.

J. B

. L

yons

.L

eban

on g

rani

te,

bord

er g

neis

s.N

H-H

-6-5

2-1.

Oli

ver

ian

plu

ton

ic

seri

es,

Mou

nt

Was

hing

ton

quad

­ ra

ngle

, N

ew H

amps

hire

.J.

B.

Lyo

ns.

Leb

anon

gra

nite

_'__

___

NH

-H-1

-52.

Han

over

qu

adra

ngle

, N

ew

Ham

pshi

re.

J. B

. L

yons

.A

plite

in

Leb

anon

gra

nit

e...

..N

H-H

-2-5

2-1.

Oli

ver

ian

plu

ton

ic

seri

es,

Han

over

qu

adra

ngle

, N

ew

Ham

pshi

re.

J. B

. L

yons

.G

rani

te o

f M

asco

ma

gro

up

..

NH

-H-5

0-52

.O

liv

eria

n

plu

tonic

se

ries

, M

asco

ma

quad

rang

le,

New

H

amps

hire

.J.

B.

Lyo

ns.

Pin

k gran

ite .

Me-

Gr-

56J-

21.

Bid

defo

rd

gran

ite,

K

enne

- bu

nk q

uadr

angl

e,

Wel

ls,

Mai

ne.

J. B

. L

yons

, H

. W

. Ja

ffe.

.do.

Zir

con

Th:

U=

2.3

c=2,

390

fc 1

.31X

10-*

Zir

con

Th

:U=

l.l

c=2,

475

fc=

l. 5

5X10

-*

Zir

con

Th:

U=

0.56

c=

2,54

0 fc

=1.

69X

10-*

Zir

con

Th:U

=0

c=2,

632

fc=

1.90

X10

-*

Zir

con

Th:

U=

1.3

c=2,

460

k=

1.50

X10

-*

Zir

con.

80+

400

100

+20

0

-100+

200

-100+

200

100

+20

0

100

+20

0

-80+

200

-200

+40

0

165

498

217

574

980

514

348

410

21,2

2 61 27 79 130

60

,63

42,4

547

,48

21.5

61.5

43.5

47.5

287

BQ1

340

337

28S

305

Do.

Mid

dle

to L

ate

Dev

onia

n (?

). B

illin

gs,

1956

, L

yons

and

ot

hers

, 19

57.

Do.

Do.

Do.

Do.

Mid

dle

to L

ate

De­

vo

nian

. L

yons

an

d ot

hers

, 19

57.

O

CO

Lead

-alp

ha a

ge d

eter

min

atio

ns o

f ac

cess

ory

min

era

ls C

onti

nued

No.

239

240

241

242

243

244

Roc

k ty

pe

Fiel

d N

o,

Loc

ality

C

olle

ctor

Gra

nite

_ _

___ _

_ _

____

____

_A

B-1

. N

ear

Par

lin

Pon

d,

Jack

man

, M

aine

. A

. J.

Bou

cot.

JBL

-Me.

N

ear

Par

lin

Pon

d,

5 m

iles

so

uth

of J

ackm

an,

Mai

ne.

J. B

. L

yons

.

AB

-2.

Kat

ahdi

n ba

thol

ith,

ne

ar

Ri-

po

genu

s da

m,

Mai

ne.

A.

J. B

ouco

t. K

ineo

rhy

olit

e, i

ntru

sive

pha

se.

AB

-3.

Nor

thea

st

par

t of

B

rass

ua

quad

rang

le,

Som

erse

t C

oun­

ty

, M

aine

. A

. J.

Bou

cot.

AB

-5.

Big

Dum

p qu

arry

, S

t. G

eorg

e,

New

Bru

nsw

ick,

Can

ada.

A

. J.

Bou

cot.

Gra

y gr

anit

e___

____

___-

_-__

_A

B-6

. S

outh

east

ti

p

of

Poc

olog

an

Har

bor,

C

harl

otte

C

ount

y,

New

B

runs

wic

k,

Can

ada.

A

. J.

Bou

cot.

Min

eral

Zir

con_

_ __

____

_

____

_do_

- ...

_ __

do --

---

___-

do-_

__ _

_

_____do____. _

___ d

o _

__

__

Mes

h si

ze

-80+

200

-80+

200

-80+

200

-20

0+

40

0

-200+

400

-80+

400

-80

+2

00

-2

00+

400

-400

aper

mg

pe

rhr

315

248

237

212

230 95 363

164

229

232

Lea

d (p

pm)

Det

erm

inat

ions 43

33,3

3 30

,29 28

30 11

45,4

5

24

,26

34

,33

34,3

6

Mea

n

33

29

.5

45 25

33.5

35

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

330

320

300

320

310

281

30-

BQ8

354

364

Cite

d ge

olog

ic ag

e of

the

rock

Mid

dle

Dev

onia

n.

A.

J. B

ouco

t.

Do.

Pos

t-E

arly

D

evo­

ni

an.

Bou

cot.

1954

.

Lat

e E

arly

D

evo­

ni

an.

A.

J.

Bou

cot.

Mid

dle

Dev

onia

n (p

ost-

Eas

tpor

t,

pre-

Per

ry f

orm

a­

tion

).

A.

J.

Bou

cot.

Pre

- Mid

dle

Sil

uria

n (?

).

A.

J. B

ouco

t.

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 111

.fS-gS orfS-1

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M

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Lead

-alp

ha a

ge d

eter

min

atio

ns o

f acc

esso

ry m

iner

als

Con

tinue

d

No.

252

253

254

255

256

257

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Sw

arth

mor

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anod

iori

te

AW

P-1

.N

ear

Spri

ngfi

eld,

Phi

lade

lphi

a ar

ea,

Pen

nsyl

vani

a.

A.

W.

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el.

AW

P-8

. N

ear

Falls

Bri

dge,

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nt

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k,

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lade

lphi

a ar

ea,

Pen

nsyl

vani

a.

A.

W.

Pos

tel.

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arth

mor

e gr

anod

iori

te.

S-23

. N

ear

Spri

ngfi

eld,

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lade

lphi

a ar

ea,

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nsyl

vani

a.

A.

W.

Post

el.

Apl

itic

phas

e,

Sw

arth

mor

e gr

anod

iori

te.

S-1

6.

Nea

r Sp

ring

fiel

d, P

hila

delp

hia

area

, P

enns

ylva

nia.

A

. W

. Po

stel

. S

war

thm

ore

gran

odio

rite

__

AW

P-5

. In

term

edia

te

repl

acem

ent

type

, E

ast

Lak

e P

ark,

Phi

l­

adel

phia

are

a, P

enns

ylva

nia.

A

. W

. Po

stel

. S

war

thm

ore

gran

odio

rite

.

AW

P-6

. In

term

edia

te

repl

acem

ent

type

, C

lifto

n H

eigh

ts,

Phil­

ad

elph

ia a

rea,

Pen

nsyl

vani

a.

A,

W. P

oste

l.

Min

eral

Zir

con.

___

..___

_

. .do

.....d

o _

_ . _

_

___ d

o _____

.....d

o _

____

__ .d

o _

___ ._

Mes

h siz

e

-80

+4

00

-80+

400

-80

+4

00

-80

+4

00

-80+

400

-80

+4

00

aper

mg

pe

rhr

297

288

240

247

220

250

Lea

d (p

pm)

Det

erm

inat

ions

25.2

8

25,2

6

28,3

0

24,2

5

20,2

3

22,2

5

Mea

n

26.5

25.5

29 24.5

21.5

23.5

Lea

d-

alph

a ag

e In

m

illio

ns

of y

ears

218

216

293

24:1

238

230

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Pos

t-P

reca

mbr

ian.

P

oste

l an

d Ja

ffe.

19

57.

Do.

Do.

Do.

Do.

Do.

to o s

to8

to a> to

b^ * *di? ^

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S'^8,S ^jg ^«j ^4 CD «T CD * j8 § <

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Lead

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ge d

eter

min

atio

ns o

f acc

esso

ry m

iner

als

Con

tinu

ed

No.

265

266

267

268

269

270

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Gra

nite

f el

soph

yre _

_ __ _ _

_C

M-2

. D

ike,

C

rab

Bot

tom

roa

d, 2

J^

mile

s no

rthe

ast

of

Hig

h-

tow

n, H

ighl

and

Cou

nty,

Va.

C

. M

ilton

. B

ento

nite

___ _ _

_ _ _

____

___

JTH

-2.

Vol

cani

c tu

ff,

7 fe

et a

bove

the

ba

se

of

the

Mar

tins

burg

sh

ale

near

Str

asbu

rg,

Va.

J.

T.

Hac

k.

Met

arhy

olit

e of

Cat

octi

n fo

r­

mat

ion.

Pa

-Sm

-fr.

S

outh

M

ount

ain,

F

rank

lin

Cou

nty,

Pa.

R

. S.

Can

non.

54J-

1.

U.S

. H

ighw

ay 2

11,

1.6

mile

s w

est o

f Spe

rry v

ille,

Va.

H

. W

. Ja

ffe.

G

ray

gran

odio

rite

gne

iss.

___

__V

R-1

. O

ne

and

seve

n-te

nths

m

iles

wes

t of S

perr

y vill

e, V

a.

R.

S.

Can

non,

H

. W

. Ja

ffe,

K

. J.

Mur

ata,

G. N

euer

berg

, an

d G

. H

. E

spen

shad

e.

Old

Rag

Gra

nite

________

OR

-1.

Min

eral

Zir

con.

.___

_ _

_

___ d

o _

__

__

___ d

o _

__

__

-_..

do

_ .__

_

.do _

_

-

Mes

h si

ze

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+2

00

-200+

400

-100+

400

-100+

200

-100+

200

-100+

200

-80+

200

a pe

r mg

perh

r 23

106 37 686

854

8,78

6

533

530

725

1,13

3

Lea

d (p

pm)

Det

erm

inat

ions

3. 0

, 3. 0

15,1

6

7. 0

, 8. 0 13

5 16

0

2,00

0

116

113

125,

128

20

0, 2

05

Mea

n 3.0

15.5

7.5

126

202

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

310

355

484

470

445

465

508

510

417

42$

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Pos

t-S

ilur

ian.

B

utts

, 19

33.

Mid

dle

to L

ate

Or-

do

vici

an.

But

ts,*

19

33.

Ear

ly C

ambr

ian

or

Pre

cam

bria

n.

Ree

d, 1

955.

Pre

cam

bria

n.

J. C

. R

eed,

Jr.

Do.

Do.

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 115

o fi

O-6

I s<5111 3*-

PM

fiOft ft

8 8(N

oCO (N

00

3

T 1

«5

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t^ ocCO tf.

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CM

o oo oCM CM+ +

CO 00I I

s

J .90

3 oN

1

8 fr "3 fl r-^ S®9

§ .PQ

!fi 1

te

son.

Henderson gra 54-O1r-207.

Rutherford County, N.C.

W. C. Overstreet.

Biotitic Whiteside granit

55Nc-7.

fourths rs, N.C.

ee- hi4S

OS sg

3 I? H ^

g(M

Lead

-alp

ha a

ge d

eter

min

atio

ns o

f acc

esso

ry m

iner

als

Con

tinu

ed

No.

277

278

279

280

281

282

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Bio

titi

c W

hite

side

gra

nite

__ _

55-N

C-5

.O

n U

.S.

Hig

hway

64

, no

rth

edge

of

Hig

hlan

ds,

N.C

. W

. R

. G

riff

itts.

55-N

C-4

. Fi

ve m

iles

wes

t of

Hig

hlan

ds,

N.C

. W

. R

. G

riff

itts.

55-N

C-3

. Fi

ve m

iles

wes

t of

Hig

hlan

ds,

N.C

.W

. R

. G

riff

itts.

B

esse

mer

gra

nite

__

. __

____

__50

L-1

74.

Tw

o an

d si

x-te

nths

m

iles

nort

heas

t of

Bes

sem

er C

ity.

N

.C.

W.

C.

Ove

rstr

eet.

Peg

mat

ite

intr

usiv

e in

to

To-

lu

ca q

uart

z m

onzo

nite

. 49

-Ot-

16.

Acr

e ro

ck

quar

ry,

Cle

vela

nd

Cou

nty,

N.C

. W

. C

. O

vers

tree

t. T

uloc

a qu

artz

mon

zoni

te__

___

49-O

t-14

. A

cre

rock

qu

arry

, C

leve

land

C

ount

y, N

.C.

W.

C.

Ove

rstr

eet.

Min

eral

Mon

azite

____

___

Zir

con_

___

..___

_

Mon

azite

_

Mes

h si

ze

-80+

200

-80

+2

00

-80+

200

-80

+2

00

-100+

200

-10

0+

20

0

-100+

200

-100+

200

a pe

r mg

perh

r

4,32

1

3,90

9

3,60

0

241

620

456

452

5,68

5

450

Lea

d (p

pm)

Det

erm

inat

ions

770,

765

780,

790

770,

760

71,7

5

130,

125 81

82

1,05

0 83

Mea

n

768

785

765

73 127

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

365

415

437

705

491

427

435

380

440

Cite

d ge

ologic

age o

f the

ro

ck

Pale

ozoi

c.

Gri

ffit

ts

and

Ove

rstr

eet,

1952

.

Do.

Do.

Do.

Do.

Do.

283

284f

285

286

287

288

289

290

Peg

mat

ite,

int

rusi

ve i

nto

To­

luca

qua

rtz

mon

zoni

te.

53-O

t-14

. A

cre

rock

qu

arry

, C

leve

land

Cou

nty,

N.C

. W

. C

. O

vers

tree

t.

Tol

uca

quar

tz m

onzo

nite

, la

teph

ase

dike

. 49

-Ot-

22.

Qua

rry

at H

olli

s,

Rut

herf

ord

Cou

nty,

N.C

. W

. C

. O

vers

tree

t.

of t

he t

ype

foun

d ne

ar T

o­

luca

. 47

-Mt-

73.

Eig

ht-t

enth

s m

ile N

.11°

W.

of

Tol

uca,

C

leve

land

C

ount

y,

N.C

. J.

B.

Mer

tie.

SO

Y-3

28.

She

lbv

area

, N

orth

C

arol

ina.

R

. G

.'Yat

es.

A48

-Ot-

81.

She

lby

area

, N

orth

C

arol

ina.

W

. C

. O

vers

tree

t.

Sch

ist

of C

arol

ina

gnei

ss__

___

48-O

t-81

. S

helb

y ar

ea,

Nor

th

Car

olin

a.

W.

C.

Ove

rstr

eet.

50-Y

-538

.S

helb

y ar

ea,

Nort

h C

arol

ina.

R

. G

. Y

ates

. S

chis

t of

Car

olin

a gn

eiss

_

__50

-Ot-

441.

S

helb

y ar

ea,

Nor

th

Car

olin

a.

W.

C.

Ove

rstr

eet.

Mon

azit

e _ _

___

Zir

con.

___

____

_

Mon

azit

e __ _

__

Zir

con.

___

____

_

Zir

con.

___

____

_M

onaz

ite _

___

_

Mon

azit

e _ _

___

-100

+ 200

-100

+200

-100 + 200

100 + 200

100 + 200

100 + 200

100 + 200

100 + 200

100 + 200

100 + 200

100 + 200

5,464

652

7,06

8

6,66

6

231

4,58

3

257

5,298

233

4,66

0

4,57

3

1,000

124

1,290

1,020 34 890 45

1,000 38 910

920

377

456

377

310

356

400

420

380

393

395

41 ?

Do.

Do.

Do.

Pre

cam

bria

n(?)

. G

riff

itts

and

O

vers

tree

t,

1952

.

Do.

Do.

Do.

Do.

O I o

d 00 GO

Lea

d-al

pha

age

dete

rmin

atio

ns o

f ac

cess

ory

min

erals

Con

tinu

ed

No.

291

292

293

294

295

296

Koc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Hom

ogen

eous

fo

liat

ed

Cra

n­

berr

y gn

eiss

, sa

prol

ite.

C

-l.

Spr

uce

Pin

e di

stri

ct,

Nor

th

Car

olin

a.

W.

R.

Gri

ffit

ts.

Hom

ogen

eous

fo

liat

ed

Cra

n­

berr

y gn

eiss

, sa

prol

ite.

C

-2.

Spr

uce

Pin

e di

stri

ct,

Nor

th

Car

olin

a.

W.

R.

Gri

ffit

ts.

Gra

nito

id b

and

in a

ugen

gne

iss.

R

G-2

. D

ellw

ood

quad

rang

le,

Hay

- w

ood

Cou

nty,

N.C

. R

. G

olds

mit

h.

Mic

a sc

hist

of

Car

olin

a gn

eiss

. _55N

C 2

O

n U

.S.

Hig

hway

64,

6.3

mile

s ea

st o

f F

rank

lin,

N.C

. W

. R

. G

riff

itts

. M

ax P

atch

gra

nit

e.. _

____

____

MP

-1.

Lem

on G

ap q

uadr

angl

e,

Max

P

atch

Mou

ntai

n, T

enn.

R

. G

olds

mit

h,

D.

Car

roll

, R

. B

. N

eum

an.

Are

nite

. _ _

____

____

____

____

__R

N-2

.O

coee

se

ries

, G

reat

S

mok

y M

ounta

ins,

G

atl

inb

urg

qu

adra

ngle

, T

enne

ssee

. R

. B

. N

eum

an.

Min

eral

Zir

con.

_ __

____

_

_.__

_do_

____

____

__

do.

_ d

o __

_ _

do._

_______

Det

rita

l zi

rcon

(f

resh

),

(met

amic

t)..

_

Mes

h si

ze

-80 +

200

-80+

200

-80+

200

-200+

400

-60+

200

-80

+2

00

-80+

200

-80+

200

a pe

r m

g per

hr 90

38

457

472

129

218 78 124

287

Lea

d (p

pm)

Det

erm

inat

ions

18,2

0

7. 0

, 8.

0

102

105

33,3

5 53

,55 31

58,5

9

104,

110

Mea

n

19 7.5

34

54 58.5

107

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

503

4:7

1

531

529

620

587

910

1,07

0

855

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Pre

cam

bria

n (?

) .

Gri

ffit

ts a

nd

Ove

rstr

eet,

195

2.

Do.

Pre

cam

bria

n.

R.

Gol

dsm

ith.

Pre

cam

bria

n.

W.

R.

Gri

ffit

ts.

Pre

cam

bria

n.

R.

Gol

dsm

ith.

Lat

e P

reca

m­

bria

n (?

) .

Kin

g,

1949

; C

arro

ll,

Neu

man

, an

d Ja

ffe,

195

7.

00

M GO s o o a o « o t-1 o 3

LEAD-ALPHA AGE DETEEMINATIONS OF IGNEOUS MINERALS 119

COto0

on oft

* o

ft oftoft

rj .&Is-" c'G-°*° T'ccW

o o«-- o I O>

00 l> US O

a> a> »o o

(NCO CO

O5

o00o"

ooCO

o o<N <N

oo<N

O O

O CO

o oCO CO § O

CO

IoCO

3*1 aI61

a o o

.53

1§ia ^ M

OJ t, OJaj a. .» *@ a

«^ »

J

^<N 3 . S«-i (B O Cj g>g

^PnO

O QJ

-^> a

OH

« S .2J-S

g

o

<u Q o a

SH

"S a

S' .w C bD

.93*;; a

.o .g a

M sf.ills

.Q-Cfl m - aj

..08 «|> fl

«sl§|5J -r .51- 5

2w ^'S I ® *

«<P501^ l)| I:

PiP^HP^

i>o>(M

CO O5 <N

i(N

O

§§ CO

Lea

d-al

pha

age

dete

rmin

atio

ns o

f ac

cess

ory

min

erals

Con

tinu

ed

No.

303

304

305

306

307

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

TB

56-1

1.

Peg

mat

itic

ne

st,

bord

er

of

ilmen

ite n

orit

e an

d an

orth

o-

site

, co

ordi

nate

s Y

21

536

and

X

3705

7,

Tel

lene

s,

Han

ge

i D

alan

e,

sout

hern

N

orw

ay.

T.

F.

W.

Ear

th.

Peg

mat

ite _

__ _

___

____

____

_T

B-1

. M

elko

doel

a, B

ygdi

n, s

outh

ern

Nor

way

. T

. F

. W

. B

arth

. P

egm

atit

e56

-1.

Stj

erno

, F

inm

ark,

so

uthe

rn

Nor

way

. T

. F.

W.

Bar

th.

Peg

mat

ite.

_

____

__

____

TB

-3.

Dik

e in

ba

sic

igne

ous

rock

, S

karv

aan,

Sei

land

, no

rthe

rn

Nor

way

. T

. F.

W.

Bar

th.

TB

-6.

Dik

e in

ig

neou

s ba

sic

rock

, Sk

arvb

ergn

es,

Seila

nd, n

orth

­ er

n N

orw

ay.

T.

F. W

. B

arth

.

Min

eral

____

_do_

____

___-

do

____

_do_

-___

____

__

__

_d

o-_

----

_

Mes

h si

ze

+ 6

0

+ 6

0

+ 6

0

+ 6

0

+ 6

0

a pe

r mg

perh

r 86 211 27 88 31

Lea

d (p

pm)

Det

erm

inat

ions

14,1

5 51

6.0

6.3 36 13

Mea

n

14.

5

6. 1

5

Lea

d-

alph

a ag

e In

m

illio

ns

of y

ears

405

573

541

930

957

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Ord

ovic

ian-

Silu

rian

H

olte

dahl

, 19

53.

Do.

Do.

Do.

Do.

308

309

310

311

312

313 »I

So

vit

e.. _

___

___ _

-__

- --

TB

-8.

Fen

are

a, s

outh

ern

Nor

way

. T

. F

. W

. B

arth

.

TB

-2.

Dik

e in

mig

mat

itic

gne

iss,

Fen

ar

ea,

sout

hern

Nor

way

. T

. F

. W

. B

arth

. G

rani

te _

__

__

__--

--_--

---

EI-

1.

Rov

anie

mi,

Fin

land

. E

. In

gers

on.

EI-

2.

Sal

onen

kala

, F

inla

nd.

E.

Inge

rson

.

EI-

3.

Bod

om,

Fin

land

. E

. In

gers

on.

Z-6

1.

Z-^S

a.

Z-l

. Z

-3.

Z-2

. Z

-2L

. Z

-4.

Z-4

a.

Z-S

b.

Z-S

c.

Z-6

3.

Z-6

3L.

Intr

usiv

e in

to Q

uana

h gr

anit

e,

Qua

nah

Mou

ntai

n, W

ichi

ta

Mou

ntai

ns,

Okl

a.

F.

L.

Hes

s, R

. L

. D

ott

. Je

an le

ad-a

lpha

age

(Okl

ahom

a zi

rcon

) of 1

---_

.do

_-_

_ ..

_. -_

_do.

__ .._

...

---.

do

.__

__

.._

_

-___-d

o -

__ _

Zir

con

(met

a-

mic

t)

Th

:U=

0.3

r 9

<\

7<\

fc=

1.77

X10

-*

Zir

con

(fre

sh)

Th:U

=3

c=2,

350

k -1

. 22X

10-*

.Z

irco

n (m

eta-

m

ict)

T

h:U

=4

c=2

,30

0

fc=

1.12

X10

-*

To. 3

13 Is

619

mill

ions

of

-60+

200

-60+

200

-60

+2

00

-60

+2

00

-80+

400

30 m

mcr

ysta

ls.

rear

s.

102 57 303

374

160

150

146

157

184

168

170

326

151

1,10

3 1,

292

1,22

0 1,

270

1,18

0 1,

230

1,19

0 1,

168

19, 2

0, 1

9, 2

1 18 100

118 52 101

101

103

120 43

45

88

41

290

350

335

380

340

360

343

339

2046

5

730

767

735

757

1,45

0 1,

510

1,45

0 1,

440

579

59S

610

618

585

601

610

66#

635

645

637

'64#

No

dat

a.

T.

F.

W.

Bar

th.

Lat

e P

reca

mbr

ian.

T

. F

. W

. B

arth

.

Pre

cam

bria

n.

A.

Kah

ma.

Do.

Do.

Lat

e P

reca

mbr

ian.

T

aylo

r, 1

915.

§ CO l^J I GO

Lea

d-al

pha

age

dete

rmin

atio

ns o

f ac

cess

ory

min

era

ls C

onti

nued

No.

314

315

316

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Tis

hom

ingo

gra

nite

, po

rphy

ri-

tic

gran

ite.

T

en A

cre

Roc

k, 8

mile

s no

rth­

w

est

of

Tis

hom

ingo

, A

r-

buck

le M

ount

ains

, O

kla.

W

. B

. H

amil

ton.

G

em-b

eari

ng

grav

els

pres

um­

ably

de

rive

d fr

om

pegm

a­

tite

-Cey

lon.

Z

-l.

Z-2

. Z

-4-3

3.

Z-3

-16.

Z

-5-1

. Z

-4-3

6.

Z-3

-11.

Z

-3.

Z-3

-42.

Z

-2-3

7.

Z-2

- 13.

Z

-4.

Z-2

-18.

Z

-2-2

3.

Z-6

. Z

-2-1

7.

Z-7

. Z

-9.

Z-l

-2.

Z-1

0.

Z-l

-26.

G-2

117.

Min

eral

Zir

con_

____

____

Zir

con

Th

:U=

<0.1

c =

2,6

32

fc=

1.9X

10-*

.

Mes

h si

ze

-60+

400

Lar

ge

crys

tals

.

-60

+2

00

a pe

r m

g pe

r hr 72

80 10

3 27

3 15

0 35

2 38

0 43

0 53

3 64

3 64

9 65

2 85

0 88

2 91

3 98

5 1,

185

1,24

5 1,

583

1,81

5 2,

040

2, 1

97

2,21

0 34

4 35

8

Lea

d (p

pm)

Det

erm

inat

ions

28,3

0 29

,31 22

65

37

80

88

91

11

5 15

0 14

3 14

8 19

6 20

5 20

0 22

7 27

5 27

0 39

2 45

0 44

0 52

9 49

8 75

85

Mea

n

29

30

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

922

845

53*

590

609

565

575

527

536

578

548

._

56S

57S

576

545

572

570

535

61S

61S

530

594

560

519

562

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Pre

cam

bria

n.

Ham

ilto

n, 1

956.

Pre

cam

bria

n.

Wad

ia a

nd F

er­

nand

o, 1

944.

Lat

o P

reca

m­

bria

n.

C.

E.

Til

ley.

317

318

319

320

321

322

Tam

bane

, N

yasa

land

, A

fric

a.C

. E

. T

ille

y.

T-l

.T

amba

ne,

Nya

sala

nd,

Afr

ica.

C

. E

. T

ille

y.

Peg

mat

ite _

__

___

___ _

.__

6208

1.

Tam

bane

, N

yasa

land

, A

fric

a.

C.

E.

Til

ley.

F

ayal

ite

ferr

ohed

enbe

rgit

egr

anit

e.

H-3

. C

ranb

erry

L

ake

quad

rang

le,

Adi

rond

ack

Mou

ntai

ns,

N.

Y.

A.

W.

Pos

tel.

Haw

keye

gr

anit

e gn

eiss

____

__P

-3.

Mud

Lak

e M

ount

ain

quar

ry,

Loo

n L

ake

quad

rang

le,

Adi

­ ro

ndac

k M

ount

ains

, N

.Y.

A.

W.

Pos

tel.

Lyo

n M

ount

ain

gran

ite _

___

_P

-l.

Adi

rond

ack

Mou

ntai

ns,

Dan

- ne

mor

a, N

.Y.

A.

W,

Pos

tel.

Hor

nble

nde

mic

rocl

ine

plag

io-

clas

e gr

anit

e gn

eiss

. 18

8.

One

hu

ndre

d se

vent

y-fi

ve

yard

s so

uthw

est

of

Sto

ne

scho

ol,

Rus

sell

qu

adra

ngle

, A

diro

ndac

k M

ount

ains

, N

. Y

. A

. F

. B

uddi

ngto

n.

-___

_do_

____

_._.

Mon

azit

e _

_ _

Zir

con

____

____

_--

_.d

o,-

_--

_._

-

-___do_._

__

_,_

_

-____dO

----

__-_

+ 6

0

+ 6

0

-60

+2

00

-60 +

200

380

489

185

375

1,63

4 73 185

187

215

213

285

86 105 47 85 430 17 51

48,5

1 48

,48 60 60 75

48

537

51 ?

600

53S

539

55S

64£

GO?

656

660

621

Do.

Do.

Pre

cam

hria

n.B

uddi

ngto

n,

1939

.

DC

.

Do.

Do.

OQ

O CO

Lea

d-al

pha

age

dete

rmin

atio

ns o

f ac

cess

ory

min

era

ls C

onti

nued

No.

323

324

325

326

Roc

k ty

pe

Fie

ld N

o.

Loc

ality

C

olle

ctor

191.

S

tark

com

plex

, 1.

5 m

iles

wes

t-

nort

hwes

t of

C

oldb

rook

sc

hool

, S

tark

qu

adra

ngle

, A

diro

ndac

k M

ount

ains

, N

. Y

. A

. F

. B

uddi

ngto

n.

Pyr

oxen

e ho

rnbl

ende

gr

anit

e gn

eiss

. 12

4.

Gar

neti

fero

us g

ranu

lite

fac

ies,

T

uppe

r L

ake

quad

rang

le,

Adi

rond

ack

Mou

ntai

ns,

N.

Y.

A.

F.

Bud

ding

ton.

P

arag

neis

s. _

____

_ __

____

____

229.

S

even

-ten

ths

of a

mile

nor

th­

east

of

road

to G

olde

n B

each

on

R

aquet

te

Lak

e qu

ad­

rang

le.

Adi

rond

ack

Mou

n­

tain

s, N

.Y.

A.

F.

Bud

ding

ton.

248.

R

aque

tte

Pon

d, s

outh

wes

t en

d of

T

uppe

r L

ake,

A

diro

n­

dack

M

ount

ains

, N

.Y.

A.

F.

Bud

ding

ton.

Min

eral

_ _

_do_

_ _ -_

__

_

do_ _

.

-__.

_do_

____

___-

Mes

h si

ze

-60 +

200

-60 +

200

-60 +

200

a pe

r m

g pe

r hr 18

8

101

130

134

Lea

d (p

pm)

Det

erm

inat

ions 50

30,2

9

34,3

6

35,3

7

Mea

n

29

.5

35

36

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

627

69ff

634

63S

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Pre

cam

bria

n.

Bud

ding

ton,

19

39.

Do.

Do.

Do.

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 1 25

O

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38.

Oswegatchie quadrangle, Adi­ rondack Mountains, N.Y.

A. F. Buddington. Hornhlftndft eranitft

C OT3 T:

42.

Oswegatchie quadrangle, Adi­ rondack Mountains, N.Y.

A. F. Buddington.

Pyroxene syenite gneiss. __ __

58SA.

Tupper Lake quadrangle, Adi­ rondack Mountains, N.Y.

A. F. Buddington. Hornblende granite

c

251.

Road cut north of Cat Pond, Tupper Lake quadrangle, Ad­

irondack Mountains, N.Y.

A. F. Buddington.

Metamorphosed limestone at contact with intrusive quartz

00 O O T-I < N <N CO CO0 CO 00 CO 00

syenite.

6-37.

Ashmore Farm, 1 mile east- northeast at Natural Bridge, Lake Bonaparte quadrangle, Adirondack Mountains,

N.Y.

A. F. Buddington, H. D. Hol­

land.

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P-4.

Goodnow Mountain quarry, Santa Clara quadrangle. Ad­ irondack Mountains, N.Y.

A. W. Postel.

<NCOCO

Lea

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pha

age

dete

rmin

atio

ns o

f ac

cess

ory

min

era

ls C

onti

nued

No.

333

334

335

336

337

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Hor

nble

nde

mic

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te

gran

ite.

B

-36.

C

ranb

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L

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quad

rang

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rond

ack

Mou

ntai

ns,

N.Y

. A

. F

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quar

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able

F

orks

qu

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, A

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bl

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orks

, A

diro

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ount

ains

, N

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A.

W.

Pos

tel.

llm

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ic m

agne

titi

c py

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nic

shon

kini

te.

4973

. D

iana

com

plex

, 1,

6 m

iles

sou

th

of

Har

risv

ille

br

idge

, A

di­

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ack

Mou

ntai

ns,

N.Y

. A

. F

. B

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ngto

n.

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nble

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gran

ite

gnei

ss__

__24

4.

One

and

one

-ten

th m

ile e

ast-

no

rthe

ast

of

road

ju

ncti

on

to

Rai

nbow

F

alls

, S

tark

qu

adra

ngle

, A

diro

ndac

k M

ount

ains

, N

.Y.

A.

F.

Bud

ding

ton.

H

ornb

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e m

icro

pert

hite

gr

anit

e.

79.

Big

M

oose

qu

adra

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, A

di­

rond

ack

Mou

ntai

ns,

N.Y

. A

. F

. B

uddi

ngto

n.

Min

eral

Zir

con

(met

a-

mic

t) .

Zir

con.

___

_ __

_

-_...d

o_. _

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_

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a-

mic

t).

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200

-60

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00

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00

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00

-60

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00

a pe

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per

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325

435

460

165

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185

310

615

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pm)

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10

5 12

5 13

0

52,

53,

55,

56 14

65

118,

120

19

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54

52 119

198

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of y

ears

755

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674

664

761

770

775

814

883

750

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Pre

cam

bria

n.

Bud

ding

ton,

19

39.

Do.

Do.

Do.

Do.

OS

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 127

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min

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s -C

on

tin

ued

No.

345

346

347

348

349

350

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Gra

nite

___

____

____

___

___

4B-4

8.

Wet

Mou

ntai

ns,

Col

o.

8.

D.

Sin

gew

ald,

M.

Bro

ck,

rani

te g

neis

s___

____

____

____

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0.

Par

agne

iss,

or

thog

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s,

or

gran

itiz

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rock

, or

igin

un

­ ce

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n,

Wet

M

ount

ains

, C

olo.

Q

. D

. S

inge

wal

d, M

. B

rock

. G

rani

te p

orp

hyry

. ___

____

____

Co-R

-Sl.

P

ark R

ange

, S

lavo

nia,

R

outt

C

ount

y, C

olo.

R

. S.

Can

non.

P

egm

atit

e _

_ _

__ _

__

_

____

Co-

R-G

oo.

Par

k R

ange

, R

outt

C

ount

y,

Col

o.

R.

S. C

anno

n.

Gra

nite

__

___

___

____

____

__W

y-F

-GM

-g.

Gra

nnie

r M

eado

w,

Fre

mon

t C

ount

y, W

yo.

R.

S. C

anno

n.

Gra

ywac

ke _

_ _

____

____

____

Wy-F

-MD

-GW

. M

iner

's D

elig

ht,

Fre

mon

t C

ount

y, W

yo.

R.

S. C

anno

n.

Min

eral

Zir

con

_ __

____

Zir

con

(met

a-

mic

t) .

Zir

con.

___

____

_

Xen

otim

e___

_ _

Zir

con

(met

a-

mic

t) .

_.__

_do_

____

____

Mes

h si

ze

-80+

200

-80+

200

-60

+2

00

-80+

400

-80

+4

00

-80

+4

00

-80

+4

00

aper

mg

per h

r 74 176

213

232

164

1,74

9 2,

390

174

140

Lea

d (p

pm)

Det

erm

inat

ions

23,2

5

95,9

8 10

5, 1

09

110,

112

55,

50,

52

1, 2

50,

1, 2

70

1, 5

50,

1, 5

60 116

130,

135

Mea

n

24 96.

5 10

7 11

1 52

1,26

0 1,

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3

Lea

d-

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a ag

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m

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of y

ears

755

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1,08

0

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1,45

0

1,95

0

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Pre

cam

bria

n. Q

. D.

Sin

gew

ald.

Do.

Pre

cam

bria

n.

R.

S.

Can

non.

Do.

Do.

Do.

00 I i QQ O § S

351

352

353

354

355

356

357

Qua

rtz

mon

zoni

te__

___

___

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DJ-

1.

Intr

usiv

e in

to S

till

wat

er c

om­

plex

, M

ouat

m

ine

area

,fa

cies

of

the

Coo

ke g

rani

te,

Sti

llw

ater

Cou

nty,

Mon

t.E

. D

. Ja

ckso

n.T

itan

ifer

ous

blac

k sa

ndst

one

of t

he L

ate

Cre

tace

ous

Mes

aver

de f

orm

atio

n.G

C-W

.G

rass

Cre

ek a

rea,

Wyo

min

g.J.

F.

Mur

phy,

R.

S. H

oust

on.

Tit

anif

erou

s bl

ack

sand

ston

eof

th

e L

ate

Cre

tace

ous

Fro

ntie

r fo

rmat

ion.

B-l

.C

umbe

rlan

d G

ap a

rea,

W

yo­

min

g.J.

F.

Mur

phy,

R.

S. H

oust

on.

Tit

anif

erou

s bl

ack

sand

ston

eof

th

e L

ate

Cre

tace

ous

Eri

cson

san

dsto

ne.

RS

-1.

Roc

k S

prin

gs a

rea,

Wyo

min

g.

J. F

. M

urph

y, R

. S.

Hou

ston

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rani

tic

gnei

ss__-_

_-_

----

- _

55ID

-60.

Min

eral

H

ill

dist

rict

, L

emhi

Cou

pjy,

Ida

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E.

P.

Kai

ser.

Ora

nit

ic g

nei

ss.-

----

__

__

55ID

-52.

Min

eral

H

ill

dist

rict

, L

emhi

Cou

nty,

Ida

ho.

E.

P.

Kai

ser.

Gra

nuli

te55

ID-5

5.M

iner

al

Hil

l di

stri

ct,

Lem

hiC

ount

y, I

daho

.E

. P

. K

aise

r.

do

Det

rita

l zi

rcon

(whi

te a

ndpu

rple

gra

ins)

.

Det

rita

l zi

rcon

(whi

te

vari

­et

y, o

nly)

.

Det

rita

l zi

rcon

(pur

ple

alon

e).

Zir

con.

___

____

_

do do

-80 +

200

-200+

400

-10

0+

40

0

-10

0+

40

0

-10

0+

40

0

-60

+2

00

-60 +

200

-60

+2

00

167

179

178

218

115

220

247 72

122,

125

135,

138

10,1

1

8. 0

, 9.

0

38,3

9

69,7

0

70,7

2

28,2

9

123

136 10 8.5

38 69.5

71 28

.5

1,55

01,

620

135 94 750

737

674

905

Pre

cam

bria

n.

Lov

-er

ing,

192

9.

Lat

e C

reta

ceou

s.M

urph

y an

dH

oust

on,

1955

.

Do.

Do.

Pre

cam

bria

n E

. P.

Kai

ser.

Do.

Do.

to CO

Lea

d-al

pha

age

dete

rmin

atio

ns o

f ac

cess

ory

min

erals

Con

tinu

ed

No.

358

359

360

361

362

363

Roc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

Gra

niti

c gn

eiss

___

___

___

___

55ID

-51.

M

iner

al

Hil

l di

stri

ct,

Lem

hi

Cou

nty,

Ida

ho.

E.

P.

Kai

ser.

G

rano

dior

ite.

_

_ _

___

___

AN

D-2

. P

resc

ott

quad

rang

le,

sout

h of

P

resc

ott,

Ari

z.

C.

A.

And

erso

n.

Qua

rtz

dior

ite_

____

____

__A

ND

-1.

Fiv

e hu

ndre

d to

one

tho

usan

d fe

et e

ast

of b

ridg

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A

sh

Cre

ek,

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rry

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ek r

oad,

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ingu

s M

ount

ain

quad

­ ra

ngle

, A

rizo

na.

C.

A.

And

erso

n.

Gra

nite

____

___

____

_ __

____

__II

.C

resc

ent

Pea

k,

McC

ullo

ugh

Mou

ntai

ns,

T.2

8S.,

R.6

1E.,

Cla

rk C

ount

y, N

ev.

R.

J. R

ober

ts.

San

dst

one.

. __

____

____

____

__H

F-1

. H

arm

ony

form

atio

n,

sec.

15

, T

.31N

., R

.43E

., A

ntle

r P

eak

quad

rang

le,

Nev

ada.

R

. J.

Rob

erts

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ray

porp

hyri

tic

horn

blen

de

gran

ite.

Min

eral

Zir

con

____

____

_

_.__

_do __ _

____

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(met

a-

mic

t) .

_ do

Det

rita

l zi

rcon

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Mes

h si

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200

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200

-60+

200

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00

-2

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400

a pe

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g pe

r hr 202

135

238

593

130

102

115

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pm)

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66,6

7 55

110

240

54,5

5

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,33

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n

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54.5

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5

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ns

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ears

765

93#

1,05

0

927

955

624

664

Cite

d ge

olog

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f the

ro

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Pre

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n.

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P.

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ser.

Pre

eam

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M.

H.

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eger

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Pre

eam

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C.

A.

And

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Lat

e C

ambr

ian.

R

. J.

Rob

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.

Lat

e C

reta

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s or

T

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(?).

CO o I o I I M

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Con

tinu

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Roc

k ty

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No.

Fi

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No.

L

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ity

Col

lect

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370

Oat

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Cre

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ranit

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____

OT

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harp

M

ount

ain

mas

s,

Lla

no

Cou

nty,

cen

tral

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as.

R.

M.

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chin

son.

37

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nite

____

____

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no C

ount

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exas

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utch

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n.

372

Tow

n M

ount

ain

gran

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____

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m

ass,

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C

ount

y, c

entr

al T

exas

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utch

inso

n.

373

Pha

coli

th

gran

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of

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intr

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TM

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no C

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n.

374

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nite

_ _

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Inte

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of

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375

Big

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gnei

ss,

mig

mat

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Min

eral

Zir

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200

-60+

200

-60+

200

-60

+2

00

-80+

200

-80

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a pe

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r hr 552

535

629

220

244

163 25 101

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pm)

Det

erm

inat

ions

205

210

230 90

95 67

9. 3

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40,4

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n 9.4

40.5

Lead

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pha

age

in

mill

ions

of

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rs

857

90.?

844

930

894

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919

Cite

d ge

olog

ic a

ge o

f the

ro

ck

Pre

cam

bria

n. S

ten-

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l, 19

32,

1935

.

Do.

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Pre

cam

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195

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LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 133

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eoi>CO

00

CO

o00 CO

Lea

d-al

pha

age

dete

rmin

atio

ns o

f ac

cess

ory

min

era

ls C

onti

nued

No.

381

382

383

384

Eoc

k ty

pe

Fiel

d N

o.

Loc

ality

C

olle

ctor

NM

-1.

Bir

thda

y ar

ea

nort

h

of

Sul­

ph

ide

Que

en

carb

onat

e bo

dy,

Mou

ntai

n P

ass,

S

an

Ber

nard

ino

Cou

nty,

Cal

if.

T.

B.

Nol

an,

W.

T.

Pec

ora.

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arit

e ca

rbon

ate

rock

___

___

_S

Q-8

1.

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t ed

ge o

f S

ulph

ide

Que

en

carb

onat

e bo

dy n

ear

its

con­

ta

ct w

ith

gnei

ss,

Mou

ntai

n Pa

ss, S

an B

erna

rdin

o C

ount

y,

Cal

if.

D.

F.

Hew

ett,

D.

R.

Sha

we.

B

ioti

te-r

ich

incl

usio

ns

in

the

Mes

ozoi

c in

trus

ive

rock

s of

th

e M

oiav

e D

eser

t.

ZC

. C

onke

y C

laim

s, Y

ucca

Val

ley,

S

an

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nard

ino

Cou

nty,

C

alif

. D

. F

. H

ewet

t.

Ash

okan

fla

gsto

ne _

____

____

__N

Y-D

a-56

-J-2

4.

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okan

fo

rmat

ion

of

the

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ilto

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oup,

ne

w r

oad

cut

on N

ew Y

ork

rout

e 32

, w

est

of

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rryv

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, C

at-

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quad

­ ra

ngle

s, N

ew Y

ork.

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. W

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ffe.

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eral

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con

(met

a-

mic

t) .

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azit

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h:U

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c=

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con

(met

a-

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t) .

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(c

ompo

site

of

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e

and

purp

le

crys

­ ta

ls).

(W

hite

cr

ys­

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alo

ne).

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h si

ze

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0

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00

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a p

er m

g pe

r hr 27

0 30

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0 1,

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0

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110

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43

43

Lea

d-

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m

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930

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d ge

olog

ic a

ge o

f the

ro

ck

Pre

-ear

ly T

erti

ary.

Ols

on a

nd o

ther

s,

1954

, p.

26;

Ja

ffe,

195

5.

Do.

Pre

- M

eso

zoic

. D

. F

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ewet

t.

Mid

dle

Dev

onia

n.

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1944

.

CO

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 135

2 s

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min

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onti

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No.

392

393

394

395

396

397

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k ty

pe

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____

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on C

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is.

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C.

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____

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399

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ory

min

era

ls C

onti

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No.

405

406

407

408

409

410

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k ty

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G

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illm

an t

onal

ite_

___

____

____

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10,

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near

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inn.

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chm

idt.

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rtz

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te _

___

__

1100

. M

yer's

qua

rry,

sec

. 13

, T

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rz,

Min

n.

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G.

Sch

mid

t. M

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1203

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4 W

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___

_ _

____

____

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65 N

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unfl

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rail

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n.

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M.

Sch

war

tz.

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nite

__ _ ___ _

____

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M-3

655.

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teri

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mas

s of

S

agan

aga

bath

olit

h,

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l L

ake,

ea

st s

ide

of C

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ber I

slan

d,

NW

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sec.

12

, T

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k C

ount

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inn.

G

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chw

artz

.

Min

eral

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con

(met

a-

mic

t) .

____

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____

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e _

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_

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00

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00

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200

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00

-2

00+

400

-80+

200

-20

0+

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0

a pe

r m

g pe

r hr 393

420

360

3,85

8

318

353

104 95 63

62

Lea

d (p

pm)

Det

erm

inat

ions

233,

236

22

9, 2

33

206,

210

3,00

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228,

232

25

5, 2

60

50,5

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57,

59

53,5

4

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n

235

231

208

230

257 50 49 58

53.

5

Lea

d-

alph

a ag

e in

m

illio

ns

of y

ears

1, 3

10

1,22

0

1,28

0

1,55

0

1,56

0 1,

570

1,08

0 1

,15

0

1,90

0 1,

800

Cit

ed g

eolo

gic

age

of th

e ro

ck

Pre

cam

bria

n (A

lgom

an?)

. G

. M

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chw

artz

.

Pre

cam

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n (A

log-

m

an?)

. R

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chm

idt,

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Pre

cam

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n.

Wyo

ski,

1949

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cam

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n (L

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. M

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chw

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Do.

00

00

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 139

o fi

oco

O v Tn fl .3

jeo- .7

OS£ 0

140 STUDIES IN1 GEOCHRONOLOGY

Geographic index of localitiesLocality No. British Territories in Borneo

West Sarawak Bau__________________________________________ 46Sebuyau.. __________________________________________ 190Tanjong Datu____--_ ___--___---_-__-_-___---______________ 47Tenting, Bedil_________..._______________________ 189

Canada Alberta

Carbon__ ___________________________________________________ 54British Columbia

Lower Arrow Lake district________ __ ____ _ _______________ 176Washington-British Columbia border____-_-____-____-___. ______ 175

Manitoba Snow Lake-Herb Lake area._- ____________,...___-_-_-__________ 391

New BrunswickSt. George.._____________________________________ 243Pocologan Harbor______________________________________________ 244

Northwest TerritoriesYamba Lake__________________________________________ 393

OntarioBurgess County _____________________________________ 388Essonville..._______________________________________________ 389Frood mine,.__________________________________. ______ 392Renfrew County____--__-_____-___--____-_-.___-____-____ 386, 387

QuebecMontreal...____________________________________ 220

Ceylon____________._____________________________ 315Finland

Bodom__________________________________________ 312Rovaniemi____________________________________________________ 310Salonenkala___________________________________________________ 311

FormosaNorthern Formosa________________________________________________ 48

FranceVosges Mountains_______________________________________________ 192

Greenland Thule area_____________._________--,_-_____-__________._ 390

MexicoBaja California______._____________ _______ 79, 80, 81, 82Chiapas

Calzada Larga________________________________________________ 191Guerrero

Acapulco. ________ _ ____ _____ _ __- 85El Ocotito ________________--______-_____-_ 83Placeres__________________________________ 86Xaltianguis___________________________________________________ 84

MorelosHuajintlan__________________________________________________ 12

Oaxaca Huilotepec__________-______-___-----_-___ ________________ 87Jalapa____-__ -_ ____ __ -- __ 88

Norway Barkevik_____----.-_-_____-___-_-__..__...._...._ _. 184, 187Djupdalen_______________________________ _______ __ 186Fen area___.____________________.__-_.-__--__.__-_____--- 308, 309Larvikofjorden_____________________--_--___-_-------_-----___--- 182Laven___________-___-_______-___-_---_-__--------__--_-_-_--- 185Melkodoela-.------ ---_-------------- -- 304Meyerfjord_____ _._ - -- -------- 188Skarvaan_ ________ ________ __ _-_ _ 306Skarvbergnes_____ __ -.. -- -- -- 307Stjerno________-__-_-_____--____-__-__--__.------------- 305Tellenes _-- -__ --- - ---- - - - 302,303Tveitdalen___-_______________- .-__ -_ ---- ... 183

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 141

Locality No. Nyasaland

Tambane__.____________________________.._ 316, 317, 318Puerto Rico

Humacao__-_-_____-_-_-___---____________-_______--_-_____-_- 62Limones _ _____________________________________________________ 61

Saudia ArabiaDhalm____________________________________________________. 197Eastern batholith_____..___-______________________________ 194JebalRafa____________________________._______ 193JebalZ'aba_____________ ________._____________ 195Taif___________________________________________________________ 196

United States Alaska

Flat area.________________________________________ 50, 51Fortymile district________-__________-__________--_-____-_--__ 177Kuskulana River area________________________________________ 180Nixon Fork mining district.- ___________________________________ 53Prince of Wales Island.__--___.________________________ 179Ruby-Poorman district_______________________________________ 52Turner Lake_________________..________._____________ 178

ArizonaMineral Park_____________________________ 366, 367Mingus Mountain quadrangle________________________-______-___ 360Prescott quadrangle__________________________________________ 359San Manuel________________________________________________ 181

California Bishop area

Big Pine quadrangle,._______________________ 123, 124, 126, 127Mount Goddard quadrangle.__ _____________________________ 121, 125Mount Tom quadrangle..______________________________ 122, 128

Kern River area____-_____-_______-_____-_---___-___-________ 130Shasta County

French Gulch quadrangle______-___-_-_____-_______-_-___- 134, 135Southern California

Aquanga___________________________________________________ 89Apple Valley______________._--____-________-_-_--_-__- 117Berdoo Canyon. ____________________________________________ 118Cottonwood Springs.________________________________________ 119Cuyumaca quadrangle-_-----_-__-__-___--_--____-__-_------- 109Descanso Junction___________________________________ 100, 103, 104Elsinore.-._______________________________ 105Green Valley__________________________________. 90, 91Ivanpah quadrangle_________________________________________ 115Lakeview_______________________________________________ 94La Posta___________.________________________ 97Mount Hole-.._-_____________________________ 101 Mount Wilson__________________________________ 98Mountain Center__________________________________________ 93Mountain Pass_______________________ 379, 380, 381, 382Neenach quadrangle.________________________________________ IllNuevo..________________________________ 99Palm Springs_______________________________-._____-__ 92Perris_______________ _______________________________________ 95Pomona Tile quarry.________________________________________ 110Providence Mountain__-__--____-__-______-______-___________ 112Rosamond quadrangle______________________________________ 114Rubidoux Mountain_-_____-_______________________________ 107, 108Shadow Mountains__________________________________________ 120Soda Lake_______________________________________________ 113Stonewall Mountain________________.________________________ 102Temecula_______________________________________________ 106Twenty Nine Palms___________________________________ 116Valverdi___________________________________________ 96Yucca Valley...._______________________________ 383

142 STUDIES IN1 GEOCHRONOLOGY

Locality No. United States Continued

California ContinuedUbehebe quadrangle.__________________________________________ 129Yosemite National Park________________________________ 131,132,133

ColoradoIron Hill_____________._______ _________________ 343Park Range.__________________________________________ 347, 348San Juan Mountains_-______---___---_--_--_-_-__ 1, 2, 3, 4, 5, 6, 7, 8, 9Wet Mountains.-___--_____-_-____--___-_--__-_-_---_- 344, 345, 346

ConnecticutMoosup______________________________________________________ 210

IdahoAtlanta. ___________________________________ 151Big Creek quadrangle______________________________ 144,145,146Bungalow. _________________________________________ 141Camas Creek____________________________________________.____ 56Cascade_-_-___-__________________________-___________________ 143Coeur d'Alene district______________________________________ 159,160Craters of the Moon.__________________________________________ 78Garden Valley. ________________________________ 153Hailey.______________________________________________________ 148Horseshoe Bend.______________________________________________ 147Idaho City_____________________________________ 155,156, 157,158Lowman_______________________________________________ 55Mineral Hill district.._____...____.____ 161,162,163, 355, 356, 357, 358South Fork Payette River_________________________ 142Placerville.___________________________________________________ 154Powell.._______________________-__-__________-_____ ____._ 152Quartzburg district.___________________________________________ 139Salmon River._____________ __________________________________ 140Stanley_______-____________--_---_-_____---___--__-_-_---_ 149,150

Maine Northern Maine

Brassua quadrangle__-____-___-____---_---__-------__-_____ 242Jackman_____________________________________ 239,240Ripogenus dam____________________________________________ 241

Southern MaineWells_-_______________________________________--_-._.______ 238

Maryland Great Falls. _____ ___ __________.____________ 272

Massachusetts Peabody____________________________________ 205

MichiganDickinson County_________________.__________ 396, 398, 399Iron County.______________.____.________-__._-___ 397

Minnesota Babbitt.-.__________________.-_______________ 404Gunfint Trail__._.__________________.________ 409Isle_________-__-_-.__-_________-____--___--____-_--__-__--_.. 400McGrath_________________________________________ 408Mount Iron_________________________________________________ 405Pierz_______________________________________ 406,407Rockville_______________________________________ 402Sea Gull Lake. _ __ _ _ . 410,411St. Cloud________________________-_--__----------__-----. 403Upper Minnesota River valley._______-_-__-_--_-_-----_-_----__ 401

MontanaBearpaw Mountains_________________-______--_-__--_____--__-_ 44, 45Boulder area____________________-_____ 66, 67, 68, 69, 70, 71, 72, 73, 74, 75Garrison___ _ ______________________---_-__----_---------_---_ 64Hamilton________________________________-__ 57, 58, 59, 60Philipsburg ____________________________-_-_---__-------__----_ 63Stillwater County._________________-________________ 351Tobacco Root Mountains________-___--_-----------------_---_- 65

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 143

Locality No. United States Continued

NevadaAntler Peak quadrangle--_-__-________________---_--___--_-__-- 362Austin..________________.___.________________ 29Bloody Run Peak_-__.__-__________________.__----- 37Boulder City_________.______________.____________ 34Copper Canyon.___-____-_______-_________-___-_-------------- 31, 32Crescent Peak____________________________-_-------_-___ 361Eureka mining district..._____________________________ 26, 27, 28Mount Lewis and Crescent Valley quadrangles.__________-_-_._-__ 41Nelson________________________________________ 33Osgood Mountains___________________________________________ 77Santa Rosa Peak._____________________________________________ 35Slumbering Hills._____________________________________________ 36Trenton Canyon_____________________________________________ 30

New HampshireBelknap Point-.. _ __._ - __ 213, 221 Cardigan quadrangle_______________________.___ 223, 227, 228Concord_____________________________________ 226Exeter. _________________________._______..____- 230Franconia quadrangle.________-____________-_--_-_----__------- 215Hanover quadrangle-._______________________ 235, 236, 247Lancaster__ ___-____-__-_-___-_____________-_--_--_--------- 248Lisbon.________________________________________ 232Littleton..____________________________________ 231,245Lovewell Mountain quadrangle__-________-______-----------_-- 222Martin______________________..__-__-________ 229Mascoma quadrangle--______-__---_-___-__-__-___--------_-_-- 237Mount Cube quadrangle________.______________---_-_-_--_---- 246Mount Chocura quadrangle-___----__-_-_----_-_--_------------- 218Mount Washington quadrangle__________________---__-_-_-__ 233, 234North Conway quadrangle______________________________ 214, 216, 217Percy quadrangle____________________________________________ 219Rumney quadrangle.__________-_________--_____-.-_-_-_---_-_- 224Sunapee quadrangle.-___-_-_-__-______-_-____-____-_-_-_---_-_- 225

New JerseyBeemerville_________._-_-__-__.______________ 249, 250, 251Dover__________________________________________________ 342New Jersey Highlands----.--------.-.----------------------- 340, 341

New MexicoBig Hatchet Peak quadrangle._----__-___--__-__-------------_-- 363Cerrillos Hills______________._.______________ 25Hachita quadrangle__________________________________________ 49Los Pinos Mountains-_________________________________________ 365Sangre de Cristo Range._-__--_-_-___-__-________-__-__-_--_-_- 364Santa Fe County..__________________________-____-_-_--_-_.- 10Valles Mountains______--______-_______-________-_-__-_----__ 13

New YorkAdirondack Mountains

Ausable Forks____________.,______________--_______-__--- 334Big Moose quadrangle.-______-______-__-_._-________-__-_-_- 337Cranberry Lake quadrangle __-_________________----------- 319, 333Dannemora. ________________________________________________ 321Harrisville bridge__________________________________________ 335Loon Lake quadrangle--______--______-_-_________--_--_-___- 320Natural Bridge__________________________________________ 331Oswegatchie quadrangle.___________________________________ 327, 328Raquette Lake quadrangle_---______________..-_-_-_-_--_-_-_ 325Russell quadrangle_________________________________________ 322Santa Clark quadrangle.--__-_--__________-___-________----_- 332Stark quadrangle..______________________________________ 323, 336Tupper Lake________.__._.___________________ 326, 339Tupper Lake quadrangle--------____________-_-_.-_ 324, 329, 330, 338

144 STUDIES IN GEOCHRONOLOGY

locality No. United States Continued

New York Continued Catskill Mountains

Quarryville_____________________________________ 384Stony Cove____________________________________.____ 385

North CarolinaBessemer City._______________________________________________ 280Cashiers_____________ _ _ _ _ _ __ ______ _ ___ _ 276Cleveland County______________________ 274, 281, 282, 283, 285Franklin__________________________________________ 294Haywood County______ __ _ _ ____________ _ 293Highlands..______________________________________ 277,278,279Rutherford...______________________ _______________ 275, 284Shelby area_______________________________ 286, 287, 288, 289, 290Spruce Pine district____________________________________ 291, 292York County-__.______________________________ 273

OklahomaArbuckle Mountains.________________________________________ 314Wichita Mountains.-._____________________________________ 313

OregonMcKenzie Bridge quadrangle________________________________.__ 24Medford quadrangle_________________________________________ 137, 138Mill City quadrangle_________________________________________ 11Sumpter quadrangle ___________________________________________ 136

PennsylvaniaEaston_________________________________________________ 264Philadelphia area

Clifton Heights______________________________ 257, 262East Lake Park___________________________________________ 256Fairmount Park_______________________________ 253, 258Springfield_______________________________________ 252, 254, 255Swarthmore_______________________________________________ 260West Manayunk_____________________________ 259, 261

Somerton_________________________________________________ 263South Mountain___________________________________ 267

Rhode IslandAshaway quadrangle_______________________ 198, 199, 200Bradford. ___________________________________ 201Ganier Memorial dam_______________________________________ 207Georgiaville quadrangle._______________________________________ 209Narragansett Pier quadrangle.__________________________________ 208Quaker Lane________________________________________________ 204Quonochontaug quadrangle _____________________________________ 203Ten Rod road_.___________________________________________ 206Tower Hill_____________________________________ 202

TennesseeGreat Smoky Mountains

Calderwood quadrangle__________________________________ 297, 300Gatlinburg quadrangle.._______________________________ 296, 301Thunderhead quadrangle.___________________________ 298, 299

Max Patch Mountain__________________________--____________ 295Texas

Blowout quadrangle_________-________________________-_____- 375, 376Llano County...______________________ 368, 369, 370, 371, 372, 373, 374Pecos County_________________________ ______ 377Schleicher County___________________________________________ 378

UtahIron Springs district_________________________--__-_-_--____- 16, 17, 18La Sal Mountains.._______________________ 19, 20,21,22,23Sheep Rock Range.__________________________________________ 14Thomas Range______________________________________________ 15Tintic district..___________________________________-.-___ 42, 43Wasatch Mountains..___________________ _______ 38,39,40

LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 145

Locality No. United States Continued

VirginiaHightown______________________________________ 265Shenandoah National Park____________________ 270, 271Sperryville________________________________ 268, 269Strasburg______________________________________ 266

VermontMount Ascutney..____________________._________ 211, 212

WashingtonArden______________________________________,_ 166Chelan quadrangle______________ _ ____________ 168, 169, 172 Holden quadrangle________________________ 170, 171, 173, 174Mount Annie._______________________________________________ 164Mount Rainier National Park_________________________________ 76Sultan quadrangle_____________________________________________ 167Tonasket___________________________________ 165

WisconsinMarathon County_____________________________________________ 395Mellen______________________________________ 394

Wyoming Cumberland Gap area________________________________________ 353Fremont County..______________________________ 349, 350 Grass Creek area_________________________________ _________ 352Rock Spring area_____________________________________-____._-_ 354

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148 STUDIES IN GEOCHRONOLOGY

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