Mass Extinctions vs. Uniformitarianism in Biological Evolution
Igneous Rocks And Relative Time - Lamont–Doherty Earth ... · Earth: Portrait of a Planet, 3rd...
Transcript of Igneous Rocks And Relative Time - Lamont–Doherty Earth ... · Earth: Portrait of a Planet, 3rd...
EESC 2200The Solid Earth System
Igneous RocksAnd Relative Time
24 Sep 08
Continental Tectonics
Homework 2:Due Wednesday
Relative Frequency of Rock Types
A. Crust B. Surface
ES101--Lect 8
Magma chemistryTwo main classes
mafic magmas + rocksma - fic
magnesium + iron (Ferrous) rich
ES101--Lect 8
felsic magmas + rocksfel - sic
Feldspar and silica rich
OR:
ES101--Lect 8
felsic ->intermediate-> mafic
light dark
large ions small ions(K, Na) (Mg, Fe)
more Si (>60%) less Si (≤ 50%)
ES101--Lect 8
felsic ->intermediate-> mafic
light dark
large cations small cations(K, Na) (Mg, Fe)
more Si (>60%) less Si (≤ 50%)
cooler magmas hotter magmas
dense mineralslight minerals
which more explosive? minerals?
ES101--Lect 8
QuartzKSparPlagSparMicasAmph.PyroxeneOlivine
Felsic Intermediate MaficUltra-mafic
ES101--Lect 8
QuartzKSparPlagSparMicasAmph.PyroxeneOlivine
Felsic Intermediate MaficUltra-mafic
Granite Gabbro Perid-otite
Diorite
ES101--Lect 8
Granite Diorite Gabbro
felsic mafic
ES101--Lect 8
Felsic Intermediate Mafic
Granite GabbroDiorite
coar
se
Rhyolite BasaltAndesite
fine
rock slides
Mafic Igneous Rocks
Gabbro (coarse) Basalt (fine)
Intermediate Igneous Rocks
Diorite (coarse) Andesite (fine)
Granite (coarse) Rhyolite (fine)
Felsic Igneous Rocks
Classifying igneous rocks bycomposition and texture
ES101-Lect9
Ridges: Mantle undergoes decompression melting --->>> Basalts (dry)
basalt = mantle melt ("blood of the Earth")
1300°C
ES101-Lect9
Depth
All Solid
AllLiqPartial
Melting
Mantle Melting 1100 °C
Temperature1300°C
LowerPressure!!
ES101-Lect9
water --> mantle wedge, --> basalt arc volcanism...
ES101-Lect9
T
Wet melting
1100˚C800˚C
you are here
H2O -- Lowers Melting Point
Depth
ES101-Lect9
basalticmagma
Olivine Olivine+Pyroxene+ Ca-f'spar
andesiticmagma
cooling
basaltic melts -> andesite melts
ES101-Lect9
Mt. St. Helens
basaltmagma
Crust
Mantle
wetfelsicmagma
H2O
H2O
ES101--Lect 8
Volcanic/Extrusive Rockscool fast, fine-grained
ES101--Lect 8
magma also cools under ground......
ES101--Lect 8
Plutonic/Intrusive Rockscool slowly, coarse-grained
ES101--Lect 8
ES101--Lect 8
ES101--Lect 8Stephen Marshak
Dike
ES101--Lect 8Paul Hoffmann
1) Relative ages
Geochronology Outline:
2. Absolute Radiometric Ages
Geologic Time
How do we determine age in the geological record?
Principles of Geochronology
Go out to the field. Observations yield relative age.
Chapter 12: Deep Time: How Old Is Old? Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak
Relative AgesRelative Ages Logical tools are useful for defining relative age.Logical tools are useful for defining relative age.
Principle of Principle of uniformitarianismuniformitarianism.. Principle of superposition.Principle of superposition. Principle of original horizontality.Principle of original horizontality. Principle of original continuity.Principle of original continuity. Principle of cross-cutting relationships.Principle of cross-cutting relationships. Principle of inclusions.Principle of inclusions. Principle of baked contacts.Principle of baked contacts.
Chapter 12: Deep Time: How Old Is Old? Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak
Geologic TimeGeologic Time Uniformitarianism Uniformitarianism –– The present is key to the past. The present is key to the past.
Physical processes that we observe today operated in thePhysical processes that we observe today operated in thesame way in the geological past.same way in the geological past.
Modern processes help us understand ancient events inModern processes help us understand ancient events inthe rock record. the rock record.
Law of Superposition
Each layer of rock is older thanthe layer above it and youngerthan the rock layer below it.
Nicolaus Steno, a Danish anatomist, geologist, and priest (1636 - 1686)
Chapter 12: Deep Time: How Old Is Old? Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak
Relative AgeRelative Age Horizontality and continuity.Horizontality and continuity.
Strata often form laterally extensive horizontal sheets.Strata often form laterally extensive horizontal sheets. Subsequent erosion dissects once-continuous layers.Subsequent erosion dissects once-continuous layers. Flat-lying rock layers are unlikely to have been disturbed.Flat-lying rock layers are unlikely to have been disturbed.
Law of Cross-cutting Relationships
A fault or dike that cuts throughanother body of rock must beyounger than the rock it cuts
Scotsman James Hutton (1726-1797)
Law of Inclusions
If a rock body (Rock B) containsfragments of another rock body (RockA), it must be younger than thefragments of rock it contains.
James Hutton
Chapter 12: Deep Time: How Old Is Old? Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak
Relative AgeRelative Age Baked contacts.Baked contacts.
Thermal metamorphism occurs when country rock isThermal metamorphism occurs when country rock isinvaded by a plutonic igneous intrusion.invaded by a plutonic igneous intrusion.
The baked rock must have been there first (it is older).The baked rock must have been there first (it is older).
Law of Faunal Successions
Fossils in rock layers appeared in apredictable sequence, within a discreteperiod of time.
William Smith
Chapter 12: Deep Time: How Old Is Old? Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak
UnconformitiesUnconformities An unconformity is a time gap in the rock record.An unconformity is a time gap in the rock record.
NondepositionNondeposition.. Erosion.Erosion.
Chapter 12: Deep Time: How Old Is Old? Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak
Relative AgeRelative Age Determining Determining relativerelative ages empowers geologists to ages empowers geologists to
easily unravel complicated geologic histories.easily unravel complicated geologic histories.
Images of Siccar point outcrop fromhttp://www.wwnorton.com/college/geo/earth2/content/index/animations.asp
James Hutton (1726-1797)
“... we find no vestige of a beginning,–no prospect of an end.”
Winchester, S., 2001, The map that changed the world: William Smith and the birth of modern geology, HarperCollins.
1801
Famennian
Givetian
Eifelian
Lochkovian
Pragian
Frasnian
Emsian
Ludfordian
Gorstian
Homerian
Sheinwoodian
Telychian
Aeronian
Rhuddanian
P h
a n
e r
o z
o i c
P a
l e
o z o
i c
Pridoli
Ludlow
Wenlock
Llandovery
Upper
Middle
Lower
Devonia
n
411.2 ±2.8
416.0 ±2.8
422.9 ±2.5
428.2 ±2.3
Lopingian
Guadalupian
Cisuralian
Upper
Upper
Middle
Middle
Lower
Lower
Upper
Upper
Middle
Middle
Lower
Lower
P h
a n
e r
o z
o i c
P a
l e
o z o
i c
M e
s o
z o
i c
Carb
onifero
us
Perm
ian
Jura
ssic
Triassic
150.8 ±4.0
155.7 ±4.0
161.2 ±4.0
164.7 ±4.0
167.7 ±3.5
171.6 ±3.0
175.6 ±2.0
183.0 ±1.5
189.6 ±1.5
196.5 ±1.0
199.6 ±0.6
203.6 ±1.5
216.5 ±2.0
228.0 ±2.0
237.0 ±2.0
245.0 ±1.5
249.7 ±0.7
251.0 ±0.4
318.1 ±1.3
260.4 ±0.7
253.8 ±0.7
265.8 ±0.7
268.0 ±0.7
270.6 ±0.7
275.6 ±0.7
284.4 ±0.7
294.6 ±0.8
299.0 ±0.8
303.9 ±0.9
306.5 ±1.0
311.7 ±1.1
Tithonian
Kimmeridgian
Oxfordian
Callovian
Bajocian
Bathonian
Aalenian
Toarcian
Pliensbachian
Sinemurian
Hettangian
Rhaetian
Norian
Carnian
Ladinian
Anisian
Olenekian
Induan
Changhsingian
Wuchiapingian
Capitanian
Wordian
Roadian
Kungurian
Artinskian
Sakmarian
Asselian
Gzhelian
Kasimovian
Moscovian
Bashkirian
Serpukhovian
Visean
Tournaisian
Pe
nn
-sylv
an
ian
Mis
sis
-sip
pia
n
359.2 ±2.5
345.3 ±2.1
326.4 ±1.6
374.5 ±2.6
385.3 ±2.6
391.8 ±2.7
397.5 ±2.7
407.0 ±2.8
443.7 ±1.5
436.0 ±1.9
439.0 ±1.8
418.7 ±2.7
Ediacaran
Cryogenian
Tonian
Stenian
Ectasian
Calymmian
Statherian
Orosirian
Rhyacian
Siderian
Neo-
proterozoic
Neoarchean
Mesoarchean
Paleoarchean
Eoarchean
Meso-
proterozoic
Paleo-
proterozoic
Arc
hean
Pro
tero
zoic
P r
e c
a m
b r
i a
n
~630
850
1000
1200
1400
1600
1800
2050
2300
2500
2800
3200
3600
Upper
Middle
Lower
Selandian
Tortonian
Serravallian
Langhian
Burdigalian
Aquitanian
Ypresian
Chattian
Rupelian
Priabonian
Danian
Thanetian
Bartonian
Lutetian
Campanian
Santonian
Turonian
Coniacian
Albian
Aptian
Berriasian
Barremian
Valanginian
Hauterivian
Maastrichtian
Cenomanian
Piacenzian
Messinian
Zanclean
Gelasian
P h
a n
e r
o z
o i c C
e n
o z
o i c
M e
s o
z o
i c
1.806
0.126
0.781
2.588
5.332
7.246
11.608
13.65
15.97
20.43
70.6 ±0.6
65.5 ±0.3
83.5 ±0.7
85.8 ±0.7
89.3 ±1.0
93.5 ±0.8
40.4 ±0.2
37.2 ±0.1
33.9 ±0.1
28.4 ±0.1
23.03
48.6 ±0.2
55.8 ±0.2
58.7 ±0.2
61.7 ±0.2
99.6 ±0.9
112.0 ±1.0
125.0 ±1.0
130.0 ±1.5
136.4 ±2.0
140.2 ±3.0
145.5 ±4.0
Cre
taceous
Pale
ogene
Neogene
Syste
mP
eriod
Eonoth
em
Eon
Era
them
Era
Sta
ge
Age
Age
Ma
GS
SP
Epoch
Series
Eonoth
em
Eon
Era
them
Era
Syste
m
Sta
ge
Age
Age
Ma
GS
SP
Epoch
Series
Period
Eonoth
em
Eon
Era
them
Era
Age
Ma
GS
SP
GS
SA
Syste
mP
eriod
Eonoth
em
Eon
Era
Sta
ge
Age
Age
Ma
GS
SP
Epoch
Series
Period
3.600
Oligocene
Eocene
Paleocene
Pliocene
Miocene
Pleistocene
Upper
Lower
Holocene0.0118
INTERNATIONAL STRATIGRAPHIC CHARTInternational Commission on Stratigraphy
421.3 ±2.6
426.2 ±2.4
Tremadocian
Darriwilian
Hirnantian
Paibian
Upper
Middle
Lower
Series 3
Stage 3
Stage 2
Stage 1
Stage 5
Stage 6
Stage 7
Stage 9
Stage 10
Stage 2
Stage 3
Stage 5
Stage 6
Stage 4Series 2
Series 1
Furongian
Cam
brian
Ord
ovic
ian
~ 503.0 *
~ 506.5 *
~ 510.0 *
~ 517.0 *
~ 521.0 *
~ 534.6 *
460.9 ±1.6
471.8 ±1.6
488.3 ±1.7
~ 492.0 *
~ 496.0 *
501.0 ± 2.0
542.0 ±1.0
455.8 ±1.6
445.6 ±1.5
468.1 ±1.6
478.6 ±1.7
Lower limit is
not defined
Silu
rian
* proposed by ICS
Era
them
Syste
m
542359.2 ±2.5145.5 ±4.0
Qu
ate
rna
ry *
ICS
Copyright © 2006 International Commission on Stratigraphy
Subdivisions of the global geologic record are formally defined by their lower boundary. Each unitof the Phanerozoic (~542 Ma to Present) and thebase of Ediacaran are defined by a basal GlobalStandard Section and Point (GSSP ), whereasPrecambrian units are formally subdivided byabsolute age (Global Standard Stratigraphic Age,GSSA). Details of each GSSP are posted on theICS website (www.stratigraphy.org). International chronostratigraphic units, rank,names and formal status are approved by theInternational Commission on Stratigraphy (ICS)and ratified by the International Union of GeologicalSciences (IUGS). Numerical ages of the unit boundaries in thePhanerozoic are subject to revision. Some stageswithin the Ordovician and Cambrian will be formallynamed upon international agreement on their GSSPlimits. Most sub-Series boundaries (e.g., Middleand Upper Aptian) are not formally defined. Colors are according to the Commission for theGeological Map of the World (www.cgmw.org). The listed numerical ages are from 'A GeologicTime Scale 2004', by F.M. Gradstein, J.G. Ogg,A.G. Smith, et al. (2004; Cambridge University Press).
This chart was drafted by Gabi Ogg. Intra Cambrian unit ageswith * are informal, and awaiting ratified definitions.