california geology science content standards for california …dbaron/ca_geologylecture.pdf ·...
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6th Grade – Focus on Earth Sciences
Students know how to explain major features of California geology(including mountains, faults, volcanoes) in terms of plate tectonics.
California GeologyScience Content Standards for California Public Schools
California Geology
From: Geologic Map of CaliforniaCalifornia Geological Survey,California Department of Conservation
www.consrv.ca.gov/CGS/information/publications/cgs_notes/note_17/note_17.pdf
http://geology.about.com/library/bl/maps/blcaliforniamap.htm
or:
For free copy, go to:
Throughout its history, California has been, attimes, the site of all three types of plateboundaries (divergent, convergent, transform)
•Before 2 billion years - ?? no rocks preserved
•1.5-1.8 billion years - ?? intensely metamorphosed rocks only
•1.2 billion years-900 million years - DIVERGENT BOUNDARY
•800-~300 million years - “passive margin”
•~300-30 million years - CONVERGENT BOUNDARY
•30 million years to present - TRANSFORM BOUNDARY
•Before 2 billion years - ?? no rocks preserved
adde
d on
late
r
*Also, Fig.6.22 in EST
•1.5-1.8 billion years - ?? intensely metamorphosed rocks only
adde
d on
late
r
DeLand (2003)
Pahrump Group sediments were deposited in arestricted, fault-bounded basin similar tothose found today where continents arebreaking up (e.g., Africa).
1.2 billion years-900 million years - divergent boundary
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Geology at a divergent plate margin Today.Sedimentation in fault-Bounded basins
From: R. Blakey, Northern Arizona University, Paleogeography of the Southwestern United States
Deposition of “Pahrump Group” sediments duringbreakup of “Rodinia” super-continent ~1.1 Byr
1.2 billion years-900 million years - Divergent boundary in CA
Death Valley
Pahrump Group: ~billion-year-old deposits in fault-bounded rift basin
Death Valley
Death Valley
Pahrump Group: ~billion-year-old deposits in failed rift arm
Death Valley
Pahrump Group: ~billion-year-old deposits in failed rift arm (aka, aulacogen)
Site ofnew ocean
N S
X-section view of Pahrump Group sediments in Amargosa rift basin
Death ValleySite of
new oceanN
S
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4 formation in Pahrump Group
KingstonRange
Saddle Peakand Ibex Hills
4 formation in Pahrump Group
KingstonRange
Saddle Peakand Ibex Hills
Crystal Springs Form
ationBeck Springs Dolomite
Beck
Spr
ings
Dol
omite Kingston Peak Form
ation
Noonday Dolomite
5 formations in Pahrump Group
KingstonRange
Saddle Peakand Ibex Hills
Crystal Springs Form
ationBeck Springs Dolomite
Beck
Spr
ings
Dol
omite Kingston Peak Form
ation
Noonday Dolomite
Crystal Springs and Becks Springs Formations
rkopp
rkopp
talc
Kingston Peak and Noonday Formations
rkopp
rkopp Kingston Peak Glacial Deposit
rkopp
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Crystal Springs stromatolites and Kingston Peak diamictite
Deposition of thick sequence (10s ofthousands of ft) of widespread sedimentlayers all along the west coast of NorthAmerica
800-~300 million years - “passive margin”
Development of a Passive Margin after Divergent Plate Margin leaves the scene
CA
Passive Margin Today: North Carolina
Passive Margin ~900-300 mya: California
underlying
Pahrump Group
extensive passive margin sediments
Paleogeography of California’s passive margin sediments
R. Blakey, Northern Arizona University
depo
sitio
n in
ext
ensi
ve la
yers
para
llel t
o co
ntin
enta
l mar
gin
5
KingstonRange
California’s passive margin sediments
KingstonRange
John
nie
Form
atio
n
California’s passive margin sediments
John
nie
Form
atio
nSt
irlin
g Fo
rmat
ion
Woo
d C
anyo
n Fo
rmat
ion
Zabr
iskie
Qua
rtzite
Northern Salt Spring Hills
California’s passive margin sedimentsPaleozoic Life: Trilobites
Trilobite track and head from Wood Canyon Formation, Salt Spring Hills Paleozoic Life: Graptolites and Archaeocyathids
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Graptolites from Inyo Range, California Archeocyathids from Inyo Range, California
Archeocyathids from Inyo Range, California Archeocyathids from Inyo Range, California
Paleozoic Life: Molluscs (Bivalves) and BrachiopodsBrachiopods from Bird Springs Formation, Salt Spring Hills, California
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Paleozoic Life: Echinoderms and ForaminiferaEchinoderms from Bird Springs Formation, Salt Spring Hills, California
Paleozoic Life: Molluscs (Cephalopods) and Brachiopods Rugose Corals from Salt Spring Hills, California
Belemnites from Salt Spring Hills, CaliforniaMetamorphic“Roof Pendants”In the Sierra Nevada
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Passive margin sediments as “Roof Pendants”in Sierra Nevada
From: Geologic Map of CaliforniaCalifornia Geological Survey,California Department of Conservation
www.consrv.ca.gov/CGS/information/publications/cgs_notes/note_17/note_17.pdf
http://geology.about.com/library/bl/maps/blcaliforniamap.htm
or:
For free copy, go to:
Passive marginsediments as “RoofPendants” in SierraNevada
Generation of magma chamber/volcanocomplexes, sedimentary basins associatedwith subduction zones plus accretion ofcontinental fragments onto western marginof North America
~300-30 million years - CONVERGENT BOUNDARY
Mesozoic – SubductionwithAccretionand Collisions
Formation of Sierra Nevada batholith 300-30 mya Remains of 100 my old volcano above Sierra batholith, Ritter Range
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Mesozoic – SubductionwithAccretionand Collisions
Mesozoic – Accretion of Terranes
Accreted Terranes in western North America and California (USGS)
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Onset of strike-slip faulting (SAF) onwestern margin of California. Northwardtranslation of subduction zone.
30 million years to present - TRANSFORM BOUNDARY
Present-Day Plate Boundaries
Continuing convergence north of Mendocino triple junction
Mt. Shasta
Mt. Lassen
Strike-slip faulting onmodern transform plateboundary
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Strike-slip faulting onmodern transform plateboundary
Strike-slip faulting onmodern transform plateboundary: transtension
Strike-slip faulting onmodern transform plateboundary: transtension
Strike-slip faulting onmodern transform plateboundary: transtension
Figure 7-7 Harden
Wright and Troxel
Death Valley “Turtleback”
Strike-slip faulting onmodern transform plateboundary: transpression
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Strike-slip faulting onmodern transform plateboundary: transpression
Transverse Ranges associated with theBig Bend in the San Andreas Fault
Harden (2004)
Pleistocene Ice Sheet in Sierra
Glacial Polish and Striations near Bishop Pass
J. Shelton
Convict Lake Moraines Faulted glacial moraines nearCrowley Lake, CA