Geological evolution and structure of Antarctica:
Geological evolution and structure of Antarctica: The ages of the following geological provinces reflect the tectonic evolution of Antarctica:
- (1) Cratons, i.e. continental cores more than 1.5 billion years old, i.e.
- (1a) the Grunehogna Craton of Dronning Maud Land,
- (1b) the Mawson Craton of Terre Adélie and Wilkes Kand,
- (1c) the Crohn Craton of the southern Prince Charles Mountains,
- (1d) the Napier Craton of Enderby Land and
- (1e) the Vestfold Hills Craton of Princess Elizabeth Land;
- (2) Grenvillian orogens ~1.1 billion years old (Maud Belt of Dronning Maud Land, Rayner Belt of Enderby and Mac.Robertson Lands, Wilkes Province Belt of Wilkes Land;
- (3) Pan-African orogens 550-500 million years old (Ross Orogen of the Transantarctic Mountains, Lützow-Holm Belt of Dronning Maud Land, Kuunga Suture of Mac.Robertson Land up to the Denman Glacier region in Queen Mary Land);
- (4) the Ellsworth Orogen of Ellsworth Land 250-200 million years old;
- (5) the Antarctic Andean Orogen of the Antarctic Peninsula formed 150-140, ~100 and since ~50 million years ago;
- (6) rift systems cross-cutting this entire architecture, mainly the Ross Sea Rift (~2000 km long, West Antarctica), the Lambert and Jutul-Penck grabens (~1000 and ~500 km long resp., both East Antarctica).
The present Antarctic Plate comprises the continent and large portions of the Southern Ocean and is nearly totally surrounded by spreading zones, that means the neighbouring plates move away from Antarctica. (Sub)recent subduction is restricted to the area of the South Shetland and South Sandwich Islands.