GEO 3200 2

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Global transgressions and regressions - what are they, when did they happen, how are they recognized?

Paleogeographic features - changes in super-continents and features through time

Fossils - which groups appear when, when do major diversifications occur?

What are they?

They are cratonic sequences, eustatic sea level changes, transgressions and regressions

When did they happen?

Sauk Transgression: Cambrian

Tippecanoe Transgression: Ordovician; terminated by evaporites

How are they recognized?

Large bodies of marine sediment deposited on continents when the oceans rose

Uncomformites that can be globally correlated

Paleozoic

Cambrian: Trace fossils, trilobites, giant predators, radiation of large animals, sediment is weakly burrowed. End of Cambrian nautoloids come, and trilobite mass extinctions

Ordovician: Stromatolites decline, coral-strom reefs, early jawless fish, sediment is now heavily burrowed

Silurian: Fishes, early land plants toward end

Devonian: Plants - seed plants, amphibians, wingless insects, LARGE coral-strom reefs

Mississippian: Amphibians, marine radiation, spore plants, seed plants

Pennsylvanian: Early reptiles, giant fixed wing insects

Permian: Folded wing insects, gynosperms, reptiles - therapsids, aragonite sponge reefs

Mesozoic

Triassic: Turtles, pterosaurs, mammals, ferns and seed ferns

Jurassic: Dinosaurs, cycads, large reefs, calcareous nanoplankton, giant sauropods towards end, earliest birds

Cretaceous: Gynosperms continue, flowering plants, marine predators diversify, rudists

Proterozoic

Archea in deep seep hydrothermal vents

Planktonic prokaryotes floated in seas and lakes

Anaerobic prokaryotes floated in seas and lakes

Emergence of eukaryotes at begining

Grypania fossils, algae resembling seaweed

No trace fossils until 560 Ma

Imprints of soft bodied organisms

Arthropods possible

Archean

Tube structures preserved in glassy material on surfaces of pillow basalts, formed by threadlike prokaryotes

Mold of prokaryotic cells

Stromatolites

Neoproterozoic

Most of Earth's landmass was in the southern hemisphere -- Gondwana, Laurentia, Siberia, Baltica

Cambrian

Cratons formed supercontinent early in Cambrian

Progressive flooding of continents, regression in middle Cambrian and again in late

Ordovician

Early - Baltica began move from south pole

End - Baltica moved to tropics

Gondwanaland nearing south pole

Glacier expanded

Sea-level fell

Mass extinction

Permian

Pangea nearly complete

Eastern N. American, undergoing erosion

Continental red beds deposited

Appalachian Mtns

Ouachita Mtns in south east

Farther west = Ancestral Rockies

Antler Mountains have eroded = highlands

Subduction and volcanism in far west

Cambrian

Laurentia is nearly covered by shallow epicontinental seas

Laurentia lies on the equator so the water is war

Deposition of sand and carbonate sediments

Water deepens toward edges of continent where hsale is deposited

Paleogeographic Features

Global transgressions and regressions

Fossils