Evolution of Neogene volcanism and stress patterns in the glaciated West Antarctic Rift, Marie Byrd Land, Antarctica

摘要: Abstract: The orientations and ages of polygenetic volcano chains, elongate edifices, summit calderas in Marie Byrd Land, Antarctica, are analysed to determine stress directions during volcanism coeval glaciation across the West Antarctic Rift. Initiation c . 36–34 Ma major beginning 14 broadly with establishment significant ice volumes Antarctica. Middle–Late Miocene occurred primarily along roughly north–south whereas latest Miocene–Pleistocene had a strong east–west preferred orientation spatial extent province. Anisotropic conditions controlled both phases volcanism, rapid rotation maximum horizontal direction from as early 6 Ma. Glacial loading unloading appears have facilitated but margin reconstructions make it unlikely that field is result flexural stresses imposed by glacial cycles. Pleistocene parallel absolute motion plate for past Ma, coincides changes Antarctic–Pacific Ridge spreading Pacific basin tectonic events associated reorganization.