Geology of Antarctica
[1][page needed] The Antarctic Peninsula was formed by uplift and metamorphism of sea-bed sediments during the late Paleozoic and the early Mesozoic eras.
Its major phase of rapid, broad extension occurred in Cretaceous time, and involved the action of both normal and strike slip faults within West Antarctica and contiguous Zealandia.
On top of this base are various more modern rocks, such as sandstones, limestones, coal and shales laid down during the Devonian and Jurassic periods to form the Transantarctic Mountains.
[10][11] The Mawson craton of East Antarctica and Australia preserves evidence of tectonic activity from the Archean through the Mesoproterozoic in the Terre Adelie, King George V Land and the Miller Range of the central Transantarctic Mountains.
Massive charnockite bodies are present in the East Antarctica complex Proterozoic mobile belts, indicating a batholith intruded the supracrustal basement gneiss around 1000 Ma.
In the Borg Massif region of western Dronning Maud Land, Archaean granites are overlain by the Proterozoic Ritscherflya Supergroup.
Precambrian gneisses, anorthosites, charnockites, and amphibolites characterize the Schirmacher Hills and Wohlthat Mountains in central Queen Maud Land.
[10][11][13][14][15][16][17][18][19] Deposition during the Precambrian occurred in deep marine basins along the Pacific margin of Gondwana, the location of the present-day Transantarctic Mountains.
The Beardmore orogeny occurred during the Late Proterozoic, and is recognized in the central Transantarctic Mountains, with Cambrian limestones unconformably overlying deformed strata.
[11]: 32, 43–44 A carbonate platform developed along the palaeo-Pacific margin of Gondwana during the Cambrian, depositing the Shackleton Limestone on top of the Late Proterzoic argillaceous turbidite Goldie Formation.
The Ross orogeny, during the early Paleozoic (Cambro-Ordovician), folded the Transantarctic Mountains along the margin of Gondwana, with associated metamorphism, and granitic batholith intrusions.
By the start of the Devonian period (416 Ma) Gondwana was in more southern latitudes and the climate was cooler, though fossils of land plants are known from this time.
Glaciation began at the end of the Devonian period (360 Ma) as Gondwana became centered on the South Pole and the climate cooled, though flora remained.
[1][page needed] Pangea began to break up during the Triassic, while Gondwana moved northward taking Antarctica way from the South pole region.
[11]: 48–51 Gondwana rifting in the Middle Jurassic resulted in voluminous tholeiitic magmtic activity throughout the Transantarctic Mountains and the Antarctic Peninsula.
