GSA Data Repository 2016016 Short magmatic residence times of quartz phenocrysts in Patagonian rhyolites associated with Gondwana breakup Susanne Seitz et al. ______________________________________________ Supplementary Material Geological Setting The volcanic El Quemado Complex is part of a large silicic igneous province associated with the Gondwana breakup. It includes the Chon Aike Province in Southern Patagonia (Fig. DR1) and related rocks from the Antarctic Peninsula (Pankhurst et al., 2000; Riley et al., 2001). The estimated volume of volcanic rocks in the Chon Aike Province is about 235,000 km 3 (Pankhurst et al., 1998), several thousand times larger than the 600-650 km 3 erupted as the Bishop Tuff during the Long Valley caldera formation (Hildreth and Wilson, 2007). Volcanism associated with the Gondwana breakup in Patagonia occurred throughout the Jurassic and is concentrated in three main volcanic episodes: between 188 and 178 Ma, between 172- 162 Ma and between 157 and 153 Ma (Pankhurst et al., 2000). The volcanic rocks of the El Quemado Complex were deposited during the last volcanic event (Fildani and Hessler, 2005; Pankhurst et al., 2000). They crop out over a large area along the Patagonian Andes (Fig. DR1), from Lago Argentino in the South to Lago Buenos Aires in the North. They consist of rhyolitic and dacitic ignimbrites and air-fall tuffs, intercalated with andesitic to rhyolitic lava flows, (Llanos et al., 2003). U/Pb dating on zircons gave ages between 153 and 156 Ma (Pankhurst et al., 2000).