welcome to es150: structural geology january 4, 2005
TRANSCRIPT
Welcome to ES150:Structural Geology
January 4, 2005
First Day Stuff• Course Objectives• Go over Syllabus• Lab Schedule• Course Calendar• Waiver• What is Structure About?• Any questions about tsunamis?• And on to…Quick overview of the state of California
What is Structural Geology?
• Study of Forces and Stress that affect and modify the solid earth
• Rock deformation resulting from that stress (= strain)– Plate scale tectonics (geologic history)– Regional scale activity (terranes)– Outcrop scale– Microscale (minerals and fine rock fabrics)
What Structure Does
• Stresses are due to tectonic plate motions
• Structures in Rocks preserve information about past stresses
• Structural geologists correlate back across time and different scales to reconstruct paleo-tectonics
Economic Reasons to do this
• Metallic Ore Deposits often reside in ancient continents collision zones and in fault breccias
• Hydrocarbon resources travel along faults and collect in the tops of folds
• Faults create hazards• Rock failure studies are important to
infrastructure• Geothermal heat in extensional faults can be
used to produce energy (with help from Ty).
Academic Reasons to Do this
• Understand Earth History - How have the continents moved in the past?
• Understand Earth Processes - How do mountain ranges form?
• Exciting field work opportunities!
Microscale
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2mm
Measured Rotation
Outcrop Scale
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Measured Local Pressure
Regional Scale
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Local Stresses Over Large Area
Plate - Scale
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Alleghanian Orogeny builds AppalachiansWhen North America hits Gondwanaland
Giant Quake and Tsunami12/26/04
http://www.ineter.gob.ni/geofisica/tsunami/com/20041226-indonesia/rupture.htm
Quake Location - First Rupture
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Moment (=energy) distribution
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OnTo
California…
A quick overview of
what structural studies have
revealed…
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MODOC PLATEAU
KLAMATHMTS
SIERRA NEVADAMICROPLATE
MOHAVEDESERT
GREAT VALLEY
COASTRANGES
BASIN &RANGE
TRANSVERSERANGES
TECTONIC REGIONS OF CALIFORNIA
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SA
N A
ND
RE
AS
FAU
LT
GARLOCKFAULT
ACTIVE FAULTING IN CALIFORNIA
SIERRA FRONT / BASIN & RANGE
JUAN DEFUCA TRENCH
Pre-CAMBRIAN (4.5Ba-570Ma)
ROCKS OF CALIFORNIA
Pre-Cambrian California
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Warm, tropical, carbonate reefLike this photo only no people and no coral yet
PALEOZOIC (570-235Ma) ROCKS OF
CALIFORNIA
Paleozoic California
Micro-continent 50-car pile-up Imagine terranes accreting west-to-east in CA
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MESOZOIC (235-65Ma) IGNEOUS
ROCKS OF CALIFORNIA
MESOZOIC (235-65Ma) DEEP
MARINE SEDIMENT
MESOZOIC (235-65Ma) SHALLOW
MARINE
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MESOZOIC CALIFORNIAPre-Sierras
Central Valley
Coast Ranges
CENOZOIC (65Ma-NOW) IGNEOUS
ROCKS OF CALIFORNIA
CENOZOIC SEDIMENT
CENOZOIC SED. CENOZOIC IG.
MESOZOIC SED. MESOZOIC IG. PALEOZOIC
Pre-CAMBRIAN
SA
N A
ND
RE
AS
FAU
LT
GARLOCKFAULT
SIERRA FRONT / BASIN & RANGE
JUAN DEFUCA TRENCH
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80 Million Yrs to Today
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