At only 66 million years long,

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Cenozoic History

• At only 66 million years long,
• the Cenozoic is only 1.4 of all geologic time
• only 20 minutes on a 24-hour clock

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Cenozoic Time Scale

• In this class we use
• the term Tertiary Period
• rather than Paleogene and Neogene Periods

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Cenozoic Plate Tectonics

• By Eocene time,
• the Americas had completely separated
• from Europe and Africa
• but India had not yet collided with Eurasia

4
Cenozoic Plate Tectonics

• During Miocene time,
• the Atlantic Ocean basin continued to widen
• and India had collided with Eurasia
• The Tethys Sea between Africa and Eurasia
• was mostly closed by this time

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Age of Ocean Basins
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Orogenic Belts

• Alpine-Himalayan orogenic belt and the
  Circum-Pacific orogenic belt are the sites of
  most recent geologic and orogenic activity

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Cenozoic Plate Tectonics

• Eocene time

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Cenozoic Plate Tectonics

• Miocene time

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The HimalayasRoof of the World

• During the Early Cretaceous,
• India broke away from Gondwana and began moving
  north
• oceanic lithosphere was consumed at a subduction
  zone along the southern margin of Asia

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Before India Collided with Asia

• Oceanic lithosphere
• subducted beneath southern Tibet as India
  approached Asia
• northern margin of India

• southern margin of Tibet

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India Collided with Asia

• About 40 to 50 million years ago, India collided
  with Asia
• but because India was to light to subduct, it
  thrust under Asia

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Continued Convergence

• Thrusting of Asian rocks
• onto the Indian subcontinent accompanied
  continued convergence

13
India Moved beneath Asia

• Since about 10 million years ago,
• India has moved beneath Asia along the main
  boundary fault

• Shallow marine sedimentary rocks
• that were deposited along Indias northern
  margin
• now form the higher parts of the Himalayas

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The Circum-Pacific Orogenic Belt
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Evolution of the Andes Mountains

• Prior to 200 million years ago,
• the west coast of South America was a passive
  continental margin
• huge quantities of sediment were deposited

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Evolution of the Andes Mountains

• Orogeny began when this area
• became an active continental margin
• as South America moved to the west and collided
  with oceanic lithosphere

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Evolution of the Andes Mountains

• Deformation, volcanism and plutonism continued

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The North American Cordillera

• The North American Cordillera
• is one large segment of the circum-Pacific
  orogenic belt
• extending from Alaska to central Mexico
• In the United States it widens to 1200 km
• stretching east-west
• from the eastern flank of the Rocky Mountains to
  the Pacific Ocean

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Cordillera
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Plate Interactions Continue

• http//earth.geol.ksu.edu/sgao/research/data/seisw
  us/example1.gif

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The Laramide Orogeny

• Third in a series of deformational events
• in the Cordillera beginning during the Late
  Jurassic
• Late Cretaceous to Eocene
• Differed from the previous orogenies in important
  ways

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Laramide orogeny

• Farallon plate, buoyed up by a mantle plume,
  subducted beneath North America at a decreasing
  angle
• igneous activity shifted inland

???
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Igneous Activity Ceased

• With nearly horizontal subduction,
• igneous activity ceased
• continental crust was deformed mostly by vertical
  uplift

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Tertiary Volcanism

• more or less continuous in the Cordillera
• varied in intensity, eruptive style, and location
  
• ceased temporarily in the area of the Laramide
  orogen

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Columbia River Basalts

• an aggregate thickness of about 2500 m
• well exposed in the walls of the deep gorges
• cut by the Columbia and Snake rivers
• Some of the individual flows were truly
  phenomenal
• Roza flow alone covers 40,000 km2 and has been
  traced about 300 km from its source

20 lava flows of the Columbia River basalts
exposed in the canyon of the Grand Ronde River in
Washington
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Cascade Range

• Some of the highest mountains in the Cordillera
  are the Cascades
• California, Oregon, Washington, British Columbia
• Thousands of volcanic vents are present
• dozen large volcanoes
• Lassen Peak in California
• world's largest lava dome
• Related to subduction of the Juan de Fuca plate

http//www.cr.nps.gov/history/online_books/resedu/
resedu2a.htm
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Basin and Range
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Basin and Range Province

• Generalized cross section of the Basin and Range
  Province
• ranges are bounded by faults

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Pacific Coast

• Before the Eocene,
• the entire Pacific Coast was a convergent plate
  boundary
• Farallon plate was consumed at a subduction zone
• stretched from Mexico to Alaska

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Change from Subduction

• As the North American Plate
• overrode the PacificFarallon Ridge,
• its margin became transform faults
• the San Andreas
• and the Queen Charlotte
• alternating with subduction zones

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Extending the San Andreas Fault

• Further overriding of the ridge
• extended the San Andreas Fault
• and diminished the size of the FarallonPlate
  remnants
• Now only two small remnants
• of the Farallon plate exist
• the Juan de Fuca and Cocos plates

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Cenozoic History of the Appalachian Mountains

• Deformation in the Appalachians has a long
  history
• began during the Late Proterozoic

• during Late Triassic time, the entire region
  experienced faulting as Pangaea fragmented

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Reduced to Plains

• By the end of the Mesozoic
• erosion had reduced the mountains to a plain
  across which streams flowed eastward to the ocean

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Appalachians in the Tertiary

• Streams developed across the plains during the
  Tertiary

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Present Appalachian Topography

• Although these mountains have a long history
• their present topographic expression resulted
  mainly from Cenozoic uplift and erosion

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The Southern and Eastern Continental Margins

• The Atlantic Coastal Plain and the Gulf Coastal
  Plain
• form a continuous belt
• from the Northeastern United States to Texas

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Coastal Plain Similarities

• Both areas have
• horizontal or gently seaward-dipping strata
• deposited mostly by streams flowing across them
• Seaward of the coastal plains
• lie the continental shelf, slope and rise,
• also areas of notable Mesozoic and Cenozoic
  deposition

http//www.missgeo.com/directors20-20mail.htm
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Gulf Coast Sedimentation Pattern

• The overall Gulf Coast sedimentation pattern
• was established during the Jurassic
• and persists today
• Sediments derived from
• Cordillera
• western Appalachians
• Interior Lowlands
• were transported toward the Gulf of Mexico
• where they were deposited in terrestrial,
  transitional, and marine environments

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Gulf-Coastal-Plain Deposition

• Cenozoic Deposition on the Gulf Coastal Plain

• Depositional provinces and surface geology

Showing facies changes and seaward thickening
Cross section of Eocene Claiborne Group
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Reservoirs for Hydrocarbons

• Many sedimentary rocks in the Gulf Coastal Plain
• are either source rocks
• or reservoirs for hydrocarbons

http//www.spe.org/specma/binary/images/1257473wor
ld_oil_production.gif
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Oil and Gas Activity!