Geology of the Southern Gerlache Strait Region, Antarctica

Abstract

Dominant rock of the southern Gerlache Strait region is a composite batholith of intermediate to basic composition. Andesitic volcanic rocks and metasedimentary units, containing clasts evidencing an older metamorphic episode, occur as roof pendants. Igneous phases yield radiometric ages of Cretaceous (94 m.y., potassium-argon) and Eocene (52.5 m.y., potassium-argon; 45 m.y., lead-alpha) and include granodiorite, quartz diorite, diorite, and gabbro. All units are intruded by Tertiary dikes of propylitized andesite and are locally covered by Pleistocene beach gravels and moraines.