California Geology Science Content Standards for California …dbaron/CA_GeologyLecture.pdf · Students know how to explain major features of California geology (including mountains,

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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

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*Also, Fig.6.22 in EST

•1.5-1.8 billion years - ?? intensely metamorphosed rocks only

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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

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X-section view of Pahrump Group sediments in Amargosa rift basin

Death ValleySite of

new oceanN

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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

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omite Kingston Peak Form

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Noonday Dolomite

5 formations in Pahrump Group

KingstonRange

Saddle Peakand Ibex Hills

Crystal Springs Form

ationBeck Springs Dolomite

Beck

Spr

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Dol

omite Kingston Peak Form

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Noonday Dolomite

Crystal Springs and Becks Springs Formations

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Kingston Peak and Noonday Formations

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rkopp Kingston Peak Glacial Deposit

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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

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KingstonRange

California’s passive margin sediments

KingstonRange

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California’s passive margin sediments

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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