Intro to Earth Sciences II
Final Exam Summary Notes
Summer 2003

major tectonic events
Rodinia; Gondwana
3 Paleozoic orogenies in eastern North America that built the Appalachians
Formation and Breakup of Pangea
Western Cordillera: formation and deformation of western North America

epeiric seas in time
sea level rose and fell through the Phanerozoic alternately flooding and exposing the continents
high sea level yielded thick sedimentary sequences across the craton
low sea level yielded major continent-wide unconformities
high sea level due to periods of rapid seafloor spreading when midocean ridge "swelled"

"Ice Ages"

Paleoproterozoic (~2.2 b.y.)

Gowganda Formation - oldest recorded glacial sediments

Neoproterozoic (~850 - 600 m.y.)

Snowball Earth

Late Paleozoic

Gondwana glaciations

Cenozoic

Antarctica (beginning ~ 35 m.y.)
northern hemisphere (beginning ~ 2-4 m.y.)

major evolutionary trends
prokaryotes and eukaryotes
rise of metazoans (multi-cellular animals)
the Cambrian Revolution
vertebrates: fish -> amphibians -> reptiles -> mammals & birds
vascular plants: spore-bearing plants -> gymnosperms -> angiosperms
mass extinctions (Permo-Triassic, Cretaceous-Tertiary)

vertebrate evolution
fish: jawless (agnathans) (late Cambrian-Recent)
acanthodians & placoderms: (Silurian-Devonian)
sharks, bony fish (ray-fins, lobe-fins): (Devonian-Recent)
tetrapods: (amphibians) first large land animals arose in late Devonian from a line of lobe-fin fish
amniotes: (reptiles) synapsids, crocodiles, turtles, snakes, dinosaurs (Carboniferous-Recent)
mammals: from synapsids to marsupials and placentals (arose from last synapsids in Triassic)
birds evolved from small dinosaurs in Jurassic

ages of terrestrial plant life

Paleophytic

Late Ordovician - Late Permian

spore-bearing plants (club mosses, ferns)

Mesophytic

Late Permian - Late Cretaceous

gymnosperms (naked seeds: conifers, ginkgos)

Cenophytic

Late Cretaceous - Recent

angiosperms (flowering plants: maples, grasses)

dominant animal groups in time

Cambrian

Age of the Trilobites

Devonian

Age of the Fishes

Carboniferous

Age of the Amphibians

Permian

Age of the "Reptiles" (synapsids)

Mesozoic

Age of the Dinosaurs

Cenozoic

Age of Mammals


Geologic Developments


Proterozoic

1

Greenville orogeny

last Precambrian addition to Laurentia collision with/formation of Rodinia?

600 m.y.

rifting - passive margin

breakout of Rodinia? --> formation of Gondwana

Phanerozoic

Building of the Appalachians and Formation of Pangea

Late Ord

Taconic orogeny

accretion of minicontinent/island arc

a clastic wedge shed from resultant mountains

Late Dev

Acadian orogeny

accretion of minicontinent along central Atlantic

Caledonian orogeny

and collision of Europe w/ Greenland & Newfoundland

Catskill and Old Red Sandstone clastic wedges

Penn-Perm

Appalachian/Alleghenian orogeny (east N.Amer)

Formation of Pangea

Mauritanide/Moroccan fold belt (NW Afr)

"

Hercynian orogeny (southern Eur)

"

Marathon/Ouachita orogeny (southern N.Amer

"

Uralian orogeny (Eur-Asia)

"

Breakup of Pangea and Gondwana

200 m.y.

Newark and other rift basins

Breakup of Pangea

175

separation of Gondwana and Laurasia

"

165

rifting of Africa from Antarctica

Breakup of Gondwana

130

separation of India from Antarctica

"

125

separation of South America from Africa

"

100

separation of Australia from Antarctica

"

85

separation of New Zealand from Antarctica

"

50

opening of the north Atlantic

Breakup of Laurasia

Western Cordillera

Late Proterozoic - early Paleozoic

passive margin

Devonian

Antler orogeny

terrane accreted

Jurassic-Cretaceous

Sierra Nevada, etc.

voluminous volcanic arc activity

rapid subduction

Late Cretaceous

Sevier orogeny

shallow subduction

Latest K -> Eocene

Larmide orogeny

flat subduction

29

beginning of ridge subduction

20 - Rec

Cordilleran extension

Basin and Range forms

San Andreas Fault zone

Cenozoic Climate

Early Cenozoic

continuation of Cretaceous greenhouse warmth

Eocene-Oligocene

global climate cools because seafloor spreading has decreased and Antarctica becomes isolated at the south pole - Antarctic glaciation begins

Pliocene

The Isthmus of Panama forms; northern hemisphere glaciation begins

Pliocene-Pleistocene

glacial cycles are controlled by variations in Earth's orbit

environmental considerations
late Paleozoic aridity within vast Pangea supercontinent with rain shadows (mountain chains) along sutures
slow cycle
   rapid seafloor spreading = high sea level = epicontinental seas = shallow marine limestones on continents
   rapid seafloor spreading = increased outgassing = increased atmospheric CO
2 = warmer climate
   (also consider the converse)
fast cycle
   cyclic variations in Earth's orbit causes cooling/warming cycles
   if Earth is in tectonic cool cycle, orbital variations cause continental ice sheets to advance and retreat
Cretaceous: Pangea breakup, much seafloor formed, Sevier/Laramide orogenies, last major epicontinental sea, warm climate
last half of Cenozoic: slow seafloor spreading, isolation of Antarctica, formation of Isthmus of Panama all lead to late Cenozoic Ice Ages with many advances and retreats of continental ice sheets in sync with orbital cycles


Evolutionary Developments

Precambrian

3.8 b.y.

organic carbon "chemical fossils" - first evidence of life ????? (probably not!)

3.5 b.y.

oldest fossil life - cyanobacteria: prokaryotes

3.5-3.2 b.y.

first stromatolites - cyanobacterial mounds

2.1-1.7 b.y.

first eukaryotes (acritarchs - single-cell true algae)

~ 630 m.y.

Ediacaran metazoans (multi-cellular animals; jelly-fish, arthropods, etc.)

Paleozoic

543 m.y.

Cambrian revolution

Early: small shellies

remainder: explosive evolutionary radiation of a great variety of animal

life; bizarre experiments and archaic forms of most important animal phyla

Late Ord

first evidence of land plants (spores) and animals (burrows)

mid Pz

Invasion of the Land - expansion of forests (spore-bearing ferns)

Penn

wide variety of "amphibians"

mid Carb

amniotes evolve: gave rise to synapsids and reptiles

Permian

spore-bearing plants lose dominant position to the gymnosperms by Late Permian and amphibians lose dominance to synapsid and sauropsid reptiles as the Pennsylvanian coal swamps give way to the arid Permian climate

Late Perm

MASS EXTINCTION - The largest known

Mesozoic

Triassic

saurischian and ornithischian dinosaurs arose, pterosaurs, marine reptiles

mammals arose as last of the synapsids

Jurassic

archaeopteryx: the first birds evolved from a group of saurischian dinosaurs

Cretaceous

angiosperms evolve and become the dominant land plants

bees and moths probably coevolved with angiosperms

diminutive forerunners of marsupials and placental mammals

K/T boundary

MASS EXTINCTION of the dinosaurs, marine reptiles, ammonites, and others

Cenozoic

Paleocene

explosive evolutionary radiation of mammals

Eo-Oligocene

mammals adapt from tropical/subtropical to savanna conditions as climate cools

Plio-Pleisto

hominid evolution (australopithecines to homo sapiens) during the ice ages

Holocene

rise of human civilization during present interglacial period

grasses

Early Cenozoic

grasses evolve

Late Oligo-Mio

continuously growing grasses evolve

grasslands spread while forests decline as climate cools

Late Miocene

7-6 m.y. many herbivores become extinct as C4 grasses (high in silica) spread

those with high-crowned teeth survive to chew on the new grasses