Episodic Silicic Volcanism in Patagonia and the Antarctic Peninsula: Chronology of Magmatism Associated with the Break-up of Gondwana

An Early Permian (ca. 280Ma) silicic igneous province in the Alxa Block, NW China: A magmatic flare-up triggered by a mantle-plume?

“…Thus, the heat required to generate these crust-derived granitoids was likely supplied by the Tarim mantle plume given that the Alxa Block was probably near its margin. A similar example is the Chon Aike SLIP (188-153 Ma) (Pankhurst et al, 1998(Pankhurst et al, , 2000, which is adjacent to the Karoo-Ferrar LIP (Pankhurst et al, 2000).…”

“…During the last two decades, a significant number of SLIPs have been recognized including the Tertiary Sierra Madre Occidental of Mexico (Bryan et al, 2002), the Early Cretaceous Whitsunday igneous province (Bryan, 2007;Bryan et al, 1997Bryan et al, , 2000, the Jurassic Chon Aike Province (Pankhurst et al, 1998(Pankhurst et al, , 2000, the Paleozoic KennedyConnors-Auburn province, northeast Australia (Bryan et al, 2003) and the Mesoproterozoic Gawler SLIP, southern Australia (Allen et al, 2008;Pankhurst et al, 2011b). These SLIPs are characterized by large volumes (N10 5 km 3 ), of predominantly rhyodacite-rhyolite compositions, long periods of magmatic evolution (b40 myr) and were located along paleo-or active continental margins (Bryan, 2007;Bryan et al, 2002).…”

“…These SLIPs are characterized by large volumes (N10 5 km 3 ), of predominantly rhyodacite-rhyolite compositions, long periods of magmatic evolution (b40 myr) and were located along paleo-or active continental margins (Bryan, 2007;Bryan et al, 2002). Unlike the mafic LIPs commonly related to mantle plumes (e.g., Bryan and Ernst, 2008;Chung et al, 1998;Coffin and Eldholm, 1994;Buchan, 2001, 2003), the mechanisms for the formation of the SLIPs are not as clear and the generation of SLIPs may be related to continental rifting, mantle plumes or back arc extension (Betts et al, 2009;Bryan, 2007;Bryan and Ferrari, 2013;Bryan et al, 2002;Pankhurst et al, 2000Pankhurst et al, , 2011b.…”

Geological evolution of the Coombs–Allan Hills area, Ferrar large igneous province, Antarctica: Debris avalanches, mafic pyroclastic density currents, phreatocauldrons

“…These authors speculate that a now-eroded sequence of silicic tuffs, perhaps up to 150 mthick, originally overlay the uppermost Lashly D sedimentary beds at Coombs Hills (Fig. 14b) (Pankhurst et al, 2000). However, on trace-element discrimination diagrams, the silicic tuffs in the Central Transantarctic Mountains plot in the "volcanic arc + syncollision" field (Elliot and Larsen, 1993, p. 402), whereas V1 rocks from the Chon Aike have a "within plate" signature (Pankhurst et al, 2000, p. 622).…”

Lower Pliensbachian caldera volcanism in high-obliquity rift systems in the western North Patagonian Massif, Argentina

“…Pankhurst and Rapela (1995) proposed a genetic evolution of this unit due to the anatexis of the Patagonian Mesoproterozoic lower crust, and considered that the dacite-rhyolite suite of this unit was formed by crystal-liquid fractionation processes derived from primary andesites. Later, Pankhurst et al (2000) included this unit within the first volcanic event (V1) related to the major episode of pre-Gondwana breakup.The western sector of the North Patagonian Massif is represented by two volcanic units whose genetic evolution is not completely understood.The Taquetrén and Garamilla formations are widespread, and are represented between the Limay River (Neuquén Province) and the Sierra de Taquetrén (Chubut Province) by compositional and lithological differences. The Taquetrén Formation consists of breccias, lavas, and a lesser amount of tuffs and ignimbrites of andesitic composition.…”