3/19/12 - Bellringer

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3/19/12 - Bellringer

• What associations are there when
• Paleo and
• Zoo
• Are part of the word?
• TURN IN TEST!

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Timeline of ALL TIME

• Review
• http//www.johnkyrk.com/evolution.html

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Chapter 23Paleozoic, Mesozoic, Cenozoic Eras

• 23.1 Paleozoic Era

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Phanerozoic Eon

• "visible life."
• 542 million years ago to the present
• Consists of three eras
• Paleozoic "ancient life" (542-251 million years
  ago)
• Mesozoic "middle life" (251-65.5 million years
  ago)
• Cenozoic "recent life" (65.5 million years ago
  to the present)

http//higheredbcs.wiley.com/legacy/college/levin/
0471697435/chap_tut/chaps/chapter10-01.html
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Paleozoic Era
http//www.geol.umd.edu/tholtz/G102/102lpal1.htm

• Early Paleozoic Cambrian, Ordovician and
  Silurian periods
• Late Paleozoic Devonian, Mississippian,
  Pennsylvanian, and Permian periods
• Long periods of sedimentation and mountain
  building.

http//higheredbcs.wiley.com/legacy/college/levin/
0471697435/chap_tut/chaps/chapter10-01.html
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Paleogeography

• Ancient geographic setting of an area defined by
  breakup of supercontinent Rodinia
• Multicellular life evolved with increasing
  complexity

http//higheredbcs.wiley.com/legacy/college/levin/
0471697435/chap_tut/chaps/chapter10-01.html
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Passive Margin

• No tectonic activity along the edge of a
  continent
• Laurentia split from Rodinia
• Located near equator
• Covered by shallow tropical sea
• No mountain ranges forming
• Completely surrounded by passive margins

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Shoreline deposition

• Evidence of sea level changes
• Tides wash sand and sediment ashore
• forms sandstone
• Deposit clay offshore
• Forms shale
• Calcium carbonate
• from sea water and
• as organisms die,
• falls to seafloor
• Forms limestone

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Transgression

• Movement of shore-line inland as sea level rises
• As level rises falls, deposition shifts
• Rise in water level, causes water to move inland
• Deep water deposits overlying shallow water
  deposits in vertical rock sequences

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Regression

• Sea level falls
• Shore moves out to the sea
• Shallow water deposits overlie deep water
  deposits in vertical rock sequences
• Evidence is found in stacked sequence of
  limestone-shale-sandstone

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Evaporites

• Rocks that have crystallized out of water that is
  saturated with dissolved minerals
• Associated with fossilized reefs
• Reefs are made from carbonate skeletons of
  organisms
• Form in long, linear mounds parallel to
  continents or islands
• Absorb energy from waves that crash against them

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Glaciation

• Sea level transgressed and regressed over 50
  times during late Paleozoic
• Reasons for change
• Climate and glaciation cycles
• Crustal subsidence and uplift
• Sedimentation rates
• Plate motions

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In-class Assignment/Homework

• Transgression/Regression Worksheet

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23.1 Notes continued
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Mountain Building

• During Ordovician Period, Laurentia collided with
  Taconic Island Arc
• Mountains began to rise in what is now
  northeastern North America
• Event known as Taconic Orogeny

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Taconic Mountains

• Added new land and an active volcanic zone along
  eastern margin of Laurentia
• Evidence found in New Yorks Taconic Mountains

http//geoscape.nrcan.gc.ca/toronto/escarp_e.php
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Deformation

• During Silurian Period, Laurentia collided with
  another landmass
• Caused folds, faults and igneous intrusions to
  already deformed rocks

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Ouachita Orogeny

• During Carbonifierous Period southeastern
  Laurentia collided with Gondwana
• Gondwana large landmass that eventually formed
  southern continents
• Formed Ouachita Mountains for Arkansas and
  Oklahoma

http//www.rockhoundingar.com/geology/ouamtns.html
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Ouachita Orogeny

• Caused crust to uplift inland as far as
  present-day Colorado
• Formed ancestral Rockies Mountains

http//jan.ucc.nau.edu/rcb7/Ancestral_Rockies.jpg
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Alleghenian Orogeny

• Gondwana continued to push against Laurentia
• Appalachian Mountains began to form
• Quite possibly taller than Himalayans when formed
• Last mountain-building event of Paleozoic
• Leads to formation of Pangaea

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In-class Assignment/Homework

• 23.1 Study Guide
• 2 Laurasia Laurentia
• Skip 8, 15, 16
• 6 650
• 13 14 649
• 17 18 650

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23.1 Notes, part C
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Paleozoic Life

• Multicellular organisms went through extensive
  diversification
• First appearance of organisms with hard parts

http//higheredbcs.wiley.com/legacy/college/levin/
0471697435/chap_tut/images/nw0237ann.jpg
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Cambrian explosion

• Geologically rapid diversification of a large
  collection of organisms in the Cambrian fossil
  record
• Burgess Shale
• Spectacular array of fossil organisms with hard
  parts

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Ordovician extinction

• More than half of marine groups that appeared
  during Cambrian became extinct
• Evidence of glacial deposits found
• When water freezes, sea level drops

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Ordovician extinction

• Most marine animals live in shallow waters on
  continental shelves
• When sea level is high many places for animals
  to live
• During regression, continental shelves become too
  narrow for life to survive

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Devonian Period

• Following Ordovician, marine life recovered and
  new species evolved
• Tremendous diversification of vertebrates
  (animals with backbones)
• Fish and first appearance of tetrapods on land
• Another extinction takes place

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Devonian extinction

• Eliminates approximately 50 of marine groups
• Caused by global cooling
• Evidence of glaciers on some continents

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http//universe-review.ca/I10-35-extinction.jpg
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Plant Life

• Ordovician and Devonian extinctions had little
  effect on land organisms
• Simple land plants begin to appear
• First plants with seeds diversified
• Seeds contain own moisture and food source
• Made them more enabled to survive change in
  environments

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Permian Period

• Largest mass extinction occurred
• Affected both marine and terrestrial organisms
• Eliminated nearly 95 of marine groups
• More than 65 of amphibians and 1/3 of insects
  did not survive

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Permian Extinction

• How did it happen?
• Many causes
• Dramatic drop in sea level from Pangaea formation
  draining shallow seas
• Extreme volcanism
• Low atmospheric oxygen levels
• A Meteorite impact

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In-class Assignment/Homework