3/19/12 - Bellringer What associations are there when… –Paleo and –Zoo Are part of the word? TURN IN TEST!

3/19/12 - Bellringer3/19/12 - Bellringer

• What associations are there when…– Paleo and– Zoo

Are part of the word?

TURN IN TEST!

Timeline of ALL TIMETimeline of ALL TIME

• Review

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

Chapter 23Chapter 23Paleozoic, Mesozoic, & Paleozoic, Mesozoic, &

Cenozoic ErasCenozoic Eras

23.1 23.1 –– Paleozoic Era Paleozoic Era

Phanerozoic EonPhanerozoic 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

Paleozoic EraPaleozoic Era– 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

http://www.geol.umd.edu/~tholtz/G102/102lpal1.htm

PaleogeographyPaleogeography

• 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

Passive MarginPassive 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

Shoreline depositionShoreline 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

TransgressionTransgression

• 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

RegressionRegression

• 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

EvaporitesEvaporites

• 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

GlaciationGlaciation

• 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

In-class Assignment/HomeworkIn-class Assignment/Homework

• Transgression/Regression Worksheet

23.1 Notes continued23.1 Notes continued

Mountain BuildingMountain 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

Taconic MountainsTaconic Mountains

• Added new land and an active volcanic zone along eastern margin of Laurentia– Evidence found in

New York’s Taconic Mountains

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

DeformationDeformation

• During Silurian Period, Laurentia collided with another landmass

• Caused folds, faults and igneous intrusions to already deformed rocks

Ouachita OrogenyOuachita 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

Ouachita OrogenyOuachita 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

Alleghenian OrogenyAlleghenian 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

In-class Assignment/HomeworkIn-class Assignment/Homework

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

23.1 Notes, part C23.1 Notes, part C

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

Cambrian explosionCambrian 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

Ordovician extinctionOrdovician extinction

• More than half of marine groups that appeared during Cambrian became extinct

• Evidence of glacial deposits found– When water freezes, sea level drops

Ordovician extinctionOrdovician 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

Devonian PeriodDevonian 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

Devonian extinctionDevonian extinction

• Eliminates approximately 50% of marine groups

• Caused by global cooling

• Evidence of glaciers on some continents

http://universe-review.ca/I10-35-extinction.jpg

Plant LifePlant 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

Permian PeriodPermian 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

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

In-class Assignment/HomeworkIn-class Assignment/Homework