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364 Geology in the Field Appendix 2 365
APPENDIX 2. Abbreviations of Geologic Terms
Abbreviations for nouns are capita lized to distinguish them from adjecti vcs (see, for example, dolomite and dolomitic). For a more extensive list, sec· M itchell,J.G., and Maher,].C., 1957, Suggested abbreviations for litholog ic descriptions: Bulletin of the American Association of Petroleum Geologists, vol. 41, p. 2103-2107.
abundant abnt clinopyroxene Cpx hypid iomorphic hypid pyritic PY acicular acic cobble Cb! igneous ign pyroxene Px actinolite Act conglomerate Cg! ignimbrite Ignm pyroxenite Pxt aggregate Aggr contact Ctc ilmeni te Ilm pyrrholite Pyrr albite Ab cordierite Cord inclusion Incl quartz Qz amorphous amor corundum Cor interbedded intbdd quartzite Qzl amount Amt cross-bedded xbdd intrusion In tr radiolarian Rad amphibole Amph cross-bedding Xbdg ir regu lar ireg reconnaissance lk con amphibolite Ampht cross-laminated xlam joint Jn t regular reg andalusite Anda! cross section X sect kaolinite Kao! rhyoli te Rhy angle L crystal XI K-feldspar Kspar rocks Rx angular ang crystalline xln laminated lam rounded rncld andesite And diameter Diam limes tone Ls sandstone Ss anhedral anhed different diff limonite Lim saturated sat anhydrite Anhy diopside Diop lithologic lith secondary sec approximate approx disseminated dissem magnet ite Mag sediment Sed arenaceous aren dolomite Doi maximum Max sedimentary secl argillaceous arg dolomitic do! member Mbr serpent ine Spt argillite Arg elevation Elev metamorph ic met s iliceous si l arkosic ark equivalent equiv microli ne Mier s ilts tone Slts t arsenopyrite Ars evaporite Evap montmorillonite Mont soluble sol asphalt ic asph exposure Exp mu clstone Mdst sphalerite Sphal average Ave feldspathic feld muscovi te Muse station Sta bedded bcld foliated fol nephcline Neph staurolite Staur bedding Being foliation Fol nodula r noel structure Struc bentonite Bent foraminifer Foram olivine 0 1 stratigraph ic strat biotite Bio formation Fm orthopyroxene Opx surficial surf bituminous bit fragmenta l frag ort hoclase Orth tabula r tab boulder Blclr glauconite Glauct outcrop Otcp temperature T brachiopocl Brach granite Gr pebble Pb! topographic topo breccia Bx granodiorite Grd pegmatite Peg tourmaline Tourm calcareous calc granular gran per idotite Perid tremolite Trem carbonaceous carb graptolite Grap permeability Perm unconformity Uncf cavernous cav graywacke Gwke phenocryst Pheno variegated vrtg cement Cmt greens tone Grnst phlogopite Phlog vegetation Veg chalcedony Chai gypsiferous gyp phosphatic phos vertebrate Vrtb chalcopyrite Cp hematitic hem plagioclase Plag volcanic vole chlorite Chi horizontal horiz point Pt volu me Vol claystone Cis t hornblende Hbl porphyritic porph wollastonite Woll cleavage Clv hornfels Hfls probable prob xenolit h Xen
372 Geology in the Field
APPENDIX 7: Symbols for Geologic Maps
65 40
2 -------
3 --- ----------
Contact:, showing dip where trace is horizontal. and strike and dip where trace is inclined
Contact, located approximately (give limits)
Contact, located very approximately, or conjectural
4 . ...... . ..... Contact, concealed beneath mapped units
5 =~"=:"=•~·='~~ Contact, gradational (optional symbols)
6 ~ Fault, nonspecific, well located (optional symbols)
7 _::-___:-;::;.:::;,,.-;;::;:: Fault, nonspecific, located approxi mately
8 ::.:-_- _:::,-_ ~ _ ~- Fault, nonspecific, assumed (existence uncertain)
g - • • •• •• • • • • • • • Fault, concealed beneath mapped units
10 ♦-75 ~ ~60
11 ~---~ ~25 32
12 + D 67 13 ♦ R
90 72
14
Fault, high-angle, showing dip (left) and approximate dips
Fault, low-angle, showing approximate dip and strike and dip
Fault. high-angle normal (D or ball and bar on downthrown side)
Fault, reverse (H on upthrown side)
Fault, high-angle st rike-slip (example is left latera l)
15 "'::= • • 36
16 • •
• T- Fault. thrust (T on ovcrthrust side)
• 0......, Fault, low-angle normal or uetachment (I) on dow n thrown side)
17 ........ -..-....--."',..--..- Fau lt, low-angle s trike-slip (example 1s right lateral)
Fault, low-angle, overturned (teeth in direction of dip)
Optional sets of symbols for different age-groups of faul ts
22
23
24
32
Fault zone or shear zone, width lo scale (dip and other accessory symbols may be added)
Faults with arrows showing plunge of rolls, grooves or slickensides
Faull showing bearing and plunge of net slip
Point of inflection (bar) on a high-angle fau lt
~ 4\ • ~ ~ Points of inflection on a strike-slip fau lt passing in to a thrust
25 -----~ 26 ~ • • .,_
27--+-- - 5
28---f l> IO D
80
29 --+--=--t -30 --t-=.-=.-:..-_-_--t--31 ··f·:.-.-.-.-. ·t····· 32 t _t ---,...f -t 33 --fr
u 34 tn 35 t:A
® 36
~~ 37
41 ___ _ .__ _ _
45
42---<L!.__ 43 ~9 }- §-+
44
45 15 15 9
46 -L..... -4:,--o 4--47 -+- -+-
48 EB
Appendix 7
Fau lt intruded by a dike
Faults associated with veins
Anticline, showing trace and plunge of hinge or cn'st li rw (specify)
Syncline (as above), showing dip of axial surface or trough surface
folds (as above), located approximately
Folds, conjectural
Folds beneath mapped units
Asymmetr ic folds with steeper limbs dipping north (optional symbols)
Anticline (top) and syncline, overturned
Antiformal (inverted) syncline
Synformal (inver ted) anticline
Antiform (top) and synform (stratigraphic sequence unknown)
Separate dome (left) and basin
Culmination tldl ) and depression
Small anticline and syncline, showing shapes in horizontal section
Vertically plunging anticline and syncline
Monocline, south-facing, showing traces of axial surfaces
Steeply plunging monoclinc or flexu re, showing trace in horizontal sect ion and plunge of hinges
Plunge of hinge lines of small folds, showing shapes in horizontal section
Strike and dip of beds or bedding
Strike and dip of overturned beds
Strike and dip of beds where stratigraphic tops are known from primary features
Strike and dip of vertical beds or bedding (dot is on s ide known to be stratigraphically the top)
Horizontal beds or bedding (as above)
373
374
49 e 40 ' _,_
50 ~ .1_ ~~
51 ~
52 _!_ 15 ~
15 '---'
53--¢- -+- 1----<
54 + + + 55_£ 1 12
i.....L..i 10 5
---"-- =:=!'!=: 56 _._ ...,._a..,._
-----il.- ~
57 =!= =#== --- •=1
Geology in the Field
Approximate (typically estimated) str ike and dip of beds
Strike of beds exact but dip approximate
Tr_ac~ of single bed, showing dip where trace is horizontal and where 1t 1s inclined
Strike and dip of foliation (optional symbols)
Strike of vertical foliation
Horizontal foliation
Strike and dip of bedding and parallel foliation
Strike and dip of joints (left) and dikes (optional symbols)
Vertica l joints (left) and dikes
58 ~+t +ft Horizontal joints (left) and dikes
59._..t_ __t__
-t2•rr
60-+- 1f.'ff= 61 + q~~r
62
63
64
- 35
:}--- 20
65 ~ 0--66
bio a--;.. --a--+
67 ---<40 ~ 15
68 ~ +-+--
69 ---+-4
70 -:;> ~
-flf-7 ~
Strike and dip of veins (optional symbols)
Vertical veins
Horizontal veins
Bearing (trend) and plunge of lineation
Vertical and horizontal lineations
Hearing and plunge of d cavage-beclding inten;ection
Bear ing and plunge of cleavage-cleavage intersections
Rea,-ings of pebble, minera l, etc. lineations
Bearing of Ii neat ions in plane of foliation
Horizontal lineation in plane of fol iation
Vertical lineation in plane of vertical foliation
Bearing of current from primary features; from upper left: general; from cross-bedding; from flute casts; from imbr ication
71 C > ~
72----j E---7
73 ~
74 ------3
75 C>-., .,___
76 T T
0-- ..... 77 M M
0-.. .......
78 ... 79 BIT
80 X
81 'X'
82 l!l l']-- ~
8'' " >-- )-+-
R4 >--< X
85 • 0 ~
86 • ¾ 87 -<>-
88 Q -6-
89 ¢ -0-
90 0
91 ~ 92 ~111,~ \\\~w, '\. .... .,..
Appendix 7
Bearing of wind direction from dune forms (left ) and crossbedding
Bearing of ice flow from striations (left) and oricn tat ion of striations
Bearing of ice flow from drumlins
Bearing of ice flow from crag and tail forms
Spring
T hermal spring
Mineral spring
Asphaltic deposit
Bituminous deposit
Sand, gravel, clay, or placer pit
Mine, quarry, or open pit
Shafts : vertical, inclined, and abandoned
Adil, open (left) and inaccessible
Trench (left) and pros pect
Water wells: flowing, nonflowing, and dry
Oil well (left) and gas well
Well dr illed for oil or gas, dry
Wells with shows of oil (left) and gas
Oil or gas well, abandoned (left) and shut in
Drilling well or well locat ion
Glory hole, open pit, or quarry, to scale
Dump or fill, to scale
375
376
APPENDIX 8:
Geology in the Field
Lithologic Patterns for Stratigraphic Columns and Cross Sections
5. Coarse sandstone
9. Graywacke
13. Dolomitecemented sandstone
17. Shale
2. Clast-supporled conglomerate
3. Matrix-supported conglomerate
6. Fine 7. Feldspathic 8. Tuffaceous sandstone sandstone sandstone
~-ti ~ ~ ~=-:~_:-q 10. Cross-bedded 11. Bedded 12. Calcite-cemented
sandstone sandstone sandstone
~ ~ ~ 14. Silly 15. Sil tstone 16. Mudslone
sandstone
18. Coal bed with carbonaceous shale
19. Pebbiy mudslone
. -
20. Calcareous shale
1'; '111
11111
:
1
11~~~ 21. Limestone 22. Cross-bedded 23. Dolomite
§1:/.1,;1 25. Calcilic dolomite
29. Bedded chert
33. Fossiliferous limestone
37. Crystalline limestone
limestone (dolostone)
~ 11111 26. Sandy 27. Clayey limestone limestone
30. Phosphorite, phosphatic shale
34. Oolitic limestone
38. Micritic limestone
31 Chalk
35. Pelletal limestone
~ 39. Algal dolomite
24. Dolomitic limestone
28. Cherly limestone
36. ln1raclas1ic limestone
~i~~ 40. Limestone conglomerate
ti~~~ 41. Limestone
breccia
45. Rock sail, salty mudstone
49. Coarse granitic rock
Ill 53. Mafic lava
K-¢HJ:,:JS!I> 4 .H, (T .H .!£ l-i
0
tt :c;:l: H:b'. H·~ 57. Hyaloclastite
61. Massive serpentirnte
65. Folded schist
69. Greenstone
73. Foliated marble
Appendix 8
~ 42. Algal dolomite
breccia
t!:::j 46. Peridotite
50. Fine granitic rock
54. Silicic lava
11 II U '1
H II U
58. Tuff
62. Foliated serpentinite
66. Semischistose sandstone
70. Silicic gneiss
74. Foliated calcsilicate rock
43. Gypsum bed, gypsiferous shale
47. Gabbro
51. Porphyritic plutonic rock
)<XXXXX )( X X ~ X
V V V V V
V V
55. Intrusive volcanic rocks
U <f' LI -0, II ~ JI
n c::l Ji Q II 0,
u o "~ u ~ ,r
59. Tuff-breccia
67. Semischistose limestone
71. Mafic gneiss
~ I>~ m--¥1 /\tt/:/: ::;t4=.#.{ .:~~ 77. Quartzite 78. Quartzite 79. Silicic
migmatite
377
~l)_l''f'0J'~] ~/A/ 44. /\11lIyd1IIO, anhy
drilic dolomllo
48. Malic pl11Ionlc 1ock
52. Porphynl1c plutonic rock
56. Pillow lava
60. Volcanic breccia
68. Semischistose gabbro
' .
72. Marble
76. Altcralio1I 7011CS
80. Malic migmalile
' .
378 Geology in the Field
APPENDIX 9: Fossil and Structure Symbols for Columnar Sections and Field Noles*
? Algae ~ Tree trunk fallen
=w Algal mats vol Trilobites
@ Ammonites ~ Vertebrates
'v Belemnites ..- Wood
-v Brachiopods - Beds distinct
y Bryozoans (=) Beds obscure
0 Corals, solitary * Un bedded
ro Corals, colonial Graded beds
lf), Crinoids ~ Planar cross-bedding
* Echinoderms ~ Trough cross-bedding
'° Echinoids ----- Ripple structures
~ Fish bones = Cut and fill
@ Pish scales is Load casts
& foraminifers, general ~ Scour casts
(J) foraminife rs . large ~ Convol ution
(:\ Fossils ~ Slumped beds
~ Fossils abundant 1l1Tr1l' Palcosol
((g) Fossils sparse 'v-'n Mud cracks
~ Gastropods DO□ Salt molds
,! Graptolites c3--0- Burrows
Q Leaves 0 Pellets
@' Ostracodes 0 Oolites
() Pelecypods © Pisolitcs
;;r Root molds <::P<::;? lntraclasts
'r Spicules f'VN, Stylolite
(r;;)I Stromatolites E) Concretion
,.A,- Tree trunk in place $ Calcitic concretion
*Chiefly after· the Standard Lege11d of the Royal Dutch/ Shell Group of Companies (Shell International Petroleum Maatschappij B. V, The Hague. July 1977)
Appendix 10 379
APPENDIX 10: Major Geochronologic and Chronostratigraphic Units in Use by the U.S. Geological Survey1
Eon or Era or Age estimates of Period or System Epoch or Series boundaries in Eonothem Erathem
millions of years2
Quaternary Holocene 0.D10 (Q) -
Pleistocene 2 (1.7- 2.2) -
Cenozoic Neogene Pliocene
5 (4.9- 5.3) -Subperiod or Miocene (Cz) Tertiary
Subsystem (N) 24 (23- 26) -
(T) Paleogene Oligocene 38 (34-38) -
Subperiod or Eocene 55 (54-56) -Subsystem (Pe) Paleocene 63 (63-66) -Cretaceous Late Upper
~ 96 (95-97) -(K) Early Lower 138 (135-141) -Mesozoic Jurassic Late Upper
(Mz) (J) Middle Middle Early Lowe,
205 (200-215) -Triassic Late Upper
(R) Middle Middle Phanerozoic Early l ower
~240 -Permian Late Upper
(P) Early Lower 290 (290-305) -
Pennsylvanian Late Upper Carbon- ( IP) Middle Middle iferous Early Lower
Periods or -330 Systems Mississippian Late Upper
Paleozoic (C) (M) Early Lower
360 (360-365) -(Pl) Devonian Late Upper \
Middle Middle (D) Early Lower 410 (405-415) -Silurian Late Upper
(S) Middle Middle Early Lower
435 (435-440)-Ordovician Late Upper
(0) Middle Middle Early Lower
500 (495-510) -Cambrian Late Upper
(£) Middle Middle Early Lower
~5702 Late Proterozoic• (Z)
900 Proterozoic -.., Middle Proterozoic' (Y) ~ (e) 1600 -.3 Early Proterozoic• (X)
C:
2500 -"' Late Archean• (W) ·;::
3000 .c -E Archean Middle Archean• (V) "' 3400 u (A) -~ Early Archean• (U) Cl. r-- ----·-·--- -- - - - --- - - --- ~ 3800?
pre-Archean (pA)-an informal time term without specific rank. 4550
l. Format modified slight ly from Sohl, N.L., and Wright, W.B. (1980, Changes;,, slmtigm/1it.ir· 1,0111r·11-
cla/u,-e by the U.S. Ceolo1?ical Survey, 1979: U.S. Geological Survey Bulletin 150~-/\, p, /\ 1,/\:!.), with Precambrian units from Harrison, J. E., and Peterman , Z.E. (1980, /\ prclrmrnary proposal for t he Precambrian of t he United States and Mexico: Geological Societyo/Americr, !Jul/1•/i11, v. 91, p. 1128-ll33). See these articles for sources of the origina l data. _
2. Ranges reflect uncertainties of isotopjc and biostratigraphic age assignmcrrn,. /\gcs of bouncl;i ncs not closely bracketed by data shown by ~-
3. A time term w ithout specific rank. 4. Time terms only.