Antarctica

Events

Age of most E. Ant. rocks

3,930,000,000 bce - 500,000,000 bce

Oldest Antarctic Rock

3,930,000,000 bce

Napier Complex - Gneiss (East Antarctica)

Rodinia Supercontinent

1,000,000,000 bce - 750,000,000 bce

SW USA connected to E Antarctica by Grenville belt of metamorphic rocks

N Am. separates from Antarctica, opens Pacific Ocean

750,000,000 bce

Events in Transantarctic Mountains

550,000,000 bce - 450,000,000 bce

Creation of Gondwana

545,000,000 bce

N Am. collides with S Am. to form Gondwana
closing of ocean basins, collision of continental blocks
metamorphism, igneous activity, mountain building
[also Cambrian/Pre-Cambrian boundary]

Subduction of Pacific Ocean under Transantarctic Mountains

545,000,000 bce - 450,000,000 bce

converging plate boundary, active margin
Ross orogeny (mountain building)
Andesite & Rhyolite at surface, Diorite & Granite below surface
Limestones metamorphosed to Marble

Age of most W. Ant. rocks

500,000,000 bce - 0 bce

Kukri Unconformity

450,000,000 bce

Tectonic shift; subduction ends and erosion occurs before continental sedimentation begins

Beacon Phase #1 - Shallow Marine-Fluvial

400,000,000 bce - 330,000,000 bce

Devonian-Carboniferous
Shallow Marine-Fluvial
Warm & Semi-Arid
primitive fish fossils

Gondwana Continental Sedimentation (Beacon Supergroup)

400,000,000 bce - 200,000,000 bce

Beacon Supergroup consists of 4 phases of sedimentation
2.5 km thick

Beacon Phase #2 - Continental Ice

330,000,000 bce - 260,000,000 bce

Carboniferous Ice World
Continental ice sheets
glacial deposits, striations

Beacon Phase #3 - Fluvial with Glossopteris Flora

260,000,000 bce - 250,000,000 bce

Permian Period
Cool temperate swamps
rapid evolution of rich flora, thriving plants
Glossopteris, ginkgos, conifers, tree ferns

End Permian Extinction

251,000,000 bce

largest extinction, 96% species extinct (esp. tropical taxa & mammal-like reptiles)
pronounced warming, sea level fall, volcanism
anoxic seas

Beacon Phase #4 - Fluvial with Dichroidium Flora

250,000,000 bce - 200,000,000 bce

warm, arid
triassic tetrapods:
Lystrosaurus, mammal-like reptile
Thrinaxodon, carnivore reptile

Subduction under Antarctic Peninsula

220,000,000 bce - 10,000,000 bce

andesite, rhyolite at surface, diorite, granite below surface
accreted ocean floor sediments (folded & faulted sedimentary rocks)

Jurassic Super Plume

200,000,000 bce - 180,000,000 bce

hot spot beneath Gondwana
may have been responsible for formation of Ellswerth Mountains (at a strange angle compared to the rest of Ant. Mountains)

Gondwana Magmatic Province

183,000,000 bce

Gondwana break-up

180,000,000 bce

preceded for 3 million years by massive volcanic eruptions
volcanic intrusions known as Ferrar Province in Antarctica (Dufek Massif gabbro)
E & W Gondwana separate

India separates from Ant; S. Am. and Africa Separate

130,000,000 bce

South Atlantic opens up

Antarctica in South Pole Position

100,000,000 bce

warm climate
vegetation of conifers, cyads, ferns, dinosaurs

Australia & NZ separate from Ant.

100,000,000 bce

mantle plume may have been involved
Marie Byrd Land - area where separation occurred

Tasman Sea Opens

80,000,000 bce

Transantarctic Mountains uplift 3-4 km

45,000,000 bce - 35,000,000 bce

Development of W. Ant. Rift System

40,000,000 bce - 0 bce

transantarctic mountains formed as a rift shoulder
some parts of W Ant. below sea level (2 km)
30-40 volcanic centres form within rift system (Mt. Erebus)
sedimentary basins in Ross Sea

First Iice sheets begin to form

35,000,000 bce

caused by opening of Drake passage

Isolation of Antarctica

35,000,000 bce

Drake passage opens up between Antarctica and S. America

Subduction ceases at Antarctic Peninsula

35,000,000 bce - 0 bce

spreading ridges collide with subduction trench
subduction continues during present day only on Drake Plate

Summer Temps 10-15 C

34,000,000 bce - 25,000,000 bce

Giant Penguins

30,000,000 bce

oligocene

Summer Temps 5-7 C

25,000,000 bce - 17,000,000 bce

Ice becomes permanent on Antarctica

20,000,000 bce - 18,000,000 bce

Last Glacial Maximum (LGM)

15,000 bce

ice sheet at maximum

Geologic Timescale

Age of the Earth

4,600,000,000 bce

Precambrian Eon

4,600,000,000 bce - 545,000,000 bce

Paleozoic Era

545,000,000 bce - 248,200,000 bce

Mesozoic Era

248,200,000 bce - 65,000,000 bce

Cenozoic Era

65,000,000 bce - 0 bce