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Figure 2.25 Rocks that have been folded and scraped off the down-going slab and
accreted to the western edge of the Antarctic Peninsula during the subduction process.
(Credit: Bryan Storey)
Gondwana, and an active volcanic mountain chain. The eroded remnants of these
volcanoes can still be seen in the deeply dissected mountains of the spine of the
Antarctic Peninsula. With the exception of the northern tip of the Antarctic
Peninsula, the subduction process has stopped along the Antarctic Peninsula
because the spreading ridge collided with the offshore Mesozoic and Cenozoic
trench leaving Antarctic devoid of plate boundaries, largely aseismic and with very
few active volcanoes.
West Antarctic Rift System
Whilst Antarctica has been left isolated at the South Pole, surrounded by the
Southern Ocean, as the original core of Gondwana, Antarctica itself continued to
rift. Marie Byrd Land moved away from East Antarctica forming what we now call
the West Antarctic Rift System (WARS). The continental crust underlying the rift
was stretched and thinned, the Transantarctic Mountains were uplifted on the
anks
of the rift to form the spectacular mountain chain that we see today and there was
associated volcanism. Volcanism in Marie Byrd Land began 36million years ago and
explosive eruptions continued until as recently as 7500 years ago. Eighteen large
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