Amalgamation of disparate crustal fragments in the Walcott Bay-Foster Glacier area, South Victoria Land, Antarctica

Abstract

Five structurally distinct crustal sub-blocks are recognised in the Walcott Bay-Foster Glacier area of South Victoria Land. The Radian sub-block consists of variably deformed greenschist and amphibolite facies metasediments, some of which have original clastic textures preserved. The Riicker sub-block is made up almost entirely of amphibolite facies marble folded into a broad synform on the 10 km scale. The Glee sub-block is made up of three parallel belts of metasediments with northeast strike. The Renegar sub-block consists of metasediments deformed around kilometre-scale plutons. The Kemp sub-block is composite, including exotic quartzofeldspathic metasediments and orthogneiss extensively altered by metamorphic muscovite. The five sub-blocks have been amalgamated into the Walcott crustal block along amphibolite facies ductile shear zones which had dominantly strike-slip motion. The Walcott Block has a northeast-striking structural grain, and has been intruded by Middle Cambrian alkaline intrusions. The numerous structural discontinuities identified in the Walcott Bay-Foster Glacier area preclude mapping of lithostratigraphy and metamorphic isograds. © 2001 Taylor & Francis Group, LLC.