Chronological study of the pre-Jurassic basement rocks of southern Patagonia

PANKHURST, R.J; RAPELA, C.W..; LOSKE, W.P.; FANNING, C.M.

Pucón

Simposio; III South American Symposium on Isotope Geology; 2001

SERNAGEOMIN

Southern Patagonia east of the Andes was the site of extensive rhyolite volcanism during the Jurassic rifting of Gondwana and subsequent shallow marine basin formation during the Cretaceous. Thus exposures of pre-Jurassic basament are extremely sparse. Nevertheless, extraction of the maximum amount of information from these scattered outcrops of granite and metamorphic rocks is crucial to assessment of the Paleozoic and earliest Mesozoic history and crustal structure of the Pacific margin of the supercontinent. In particular, the identification and possible correlation of early terrane accretion on this margin depends on comparison of pre-Jurassic igneous and metamorphic events with adjacent areas. This is a preliminary report on work now in progress to this end.