The ocean floor of Rocas Verdes Basin in Tierra del Fuego, Argentina.

M.E. CERREDO; A.A. TASSONE ; M.B. REMESAL ; J.F. VILAS

Mendoza

Conferencia; Gondwana 12 Conference ?Geological and Biological Heritage of Gondwana; 2005

Gondwana Conference ?Geological and Biological Heritage of Gondwana

The Rocas Verdes back-arc basin (RVB) evolved along the SW border of Gondwana from Late Jurassic to Early Cretaceous (Dalziel, 1981; Stern et al., 1992; Mukasa and Dalziel, 1996) after a widespread event of continental rifting and associated, mostly silicic, magmatic activity. The latter encompasses Middle to Late Jurassic volcanic rocks of Patagonia and the Antarctic Peninsula, (Pankhurst et al., 2000; Rilley et al., 2001) along the palaeo-Pacific margin of Gondwana. Remnants of the oceanic floor of the RVB are represented by the ophiolite complexes of Sarmiento at the NW tip of the basin, Tortuga in southern Chilean archipelago and the Larsen Harbour Complex of South Georgia. These complexes display a fairly complete oceanic upper crustal section including gabbros, a sheeted dyke complex and pillow-lavas and breccias (Stern and de Wit, 2003). Restricted outcrops of basaltic rocks in Tierra del Fuego have been considered as representing a phase of the same igneous event that formed the Rocas Verdes ophiolite complexes (Stern and