Permian-Carboniferous and Permian-Triassic magmatism in the rift zone bordering the Tethyan margin of southern Pangea

Magma was emplaced in the India-Australia rift zone along the Tethyan margin during Permian-Carboniferous and Permian-Triassic time. Permian-Carboniferous alkalic granite and basaltic and rhyolitic lava flows and tuffs formed at the same time as right-lateral transtension of angea, as recorded by the magmatic rocks of neocratonic post-Variscan Europe and post-Kanimblan eastern Australia. Permian-Triassic tholeiitic basalt in India, alkalic magmatic rocks in Oman, and rhyolite, dolerite, and undersaturated alkalic volcanic rocks in Western Australia preceded and accompanied the early opening of the Neo-Tethys ocean. Coeval magmatism included the voluminous mid-plate Siberian Traps, the Emeishan Basalt of south China, and the peak activity of the magmatic arc along the convergent Panthalassan margin. The background magmatism probably permitted the Siberian Traps to trigger the environmental catastrophe at the Permian-Triassic boundary.