1. 3/19/12 - Bellringer What associations are there when…
Paleo and
Zoo
Are part of the word?
TURN IN TEST!

2. Timeline of ALL TIME
Review

3. Chapter 23 Paleozoic, Mesozoic, & Cenozoic Eras
23.1 – Paleozoic Era

4. Phanerozoic Eon "visible life." 542 million years ago to the present
Consists of three eras
Paleozoic = "ancient life" ( million years ago)
Mesozoic = "middle life" ( million years ago)
Cenozoic = "recent life" (65.5 million years ago to the present)

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

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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. In-class Assignment/Homework
Transgression/Regression Worksheet

14. 23.1 Notes continued

15. 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

16. Taconic Mountains
Added new land and an active volcanic zone along eastern margin of Laurentia
Evidence found in New York’s Taconic Mountains

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

18. 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

19. Ouachita Orogeny
Caused crust to uplift inland as far as present-day Colorado
Formed ancestral Rockies Mountains

20. 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

21. In-class Assignment/Homework
23.1 Study Guide
#2 = Laurasia = Laurentia
Skip #8, 15, 16
#6 = 650
#13 & 14 = 649
#17 & 18 = 650

22. 23.1 Notes, part C

23. Paleozoic Life
Multicellular organisms went through extensive diversification
First appearance of organisms with hard parts

24. 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

25. 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

26. 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

27. 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

28. Devonian extinction Eliminates approximately 50% of marine groups
Caused by global cooling
Evidence of glaciers on some continents

30. 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

31. 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

32. 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

33. In-class Assignment/Homework