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 subblocks 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 BayFoster Glacier area preclude mapping of lithostratigraphy and metamorphic isograds.

Geology, geochemistry, and geochronology of an A‐type granite in the Mulock Glacier area, southern Victoria Land, Antarctica

“…The Skelton Group was subsequently divided into two groups by Grindley & Warren (1964) on the basis of metamorphic grade-the greenschist facies Skelton Group and the amphibolite facies Koettlitz Group. Cook & Craw (2001) argued that the name Koettlitz Group be abandoned and suggested returning to the original name Skelton Group.…”

“…1) consist of multiply deformed, greenschist to upper amphibolite facies metasediments of the Skelton Group (Gunn & Warren 1962;Allibone 1992;Cox 1992;Cook 1997;Cook & Craw 2001. The Skelton Group and associated orthogneisses are intruded by undeformed plutons of the Granite Harbour Intrusives (Gunn & Warren 1962).…”

Provenance signatures of the Antarctic Ice Sheets in the Ross Embayment during the Late Miocene to Early Pliocene: The ANDRILL AND-1B core record

“…In the Ferrar-Koettlitz glacier area, upper amphibolite-facies to upper greenschist-facies metamorphic rocks of the Koettlitz Group (Cook and Craw, 2001;Talarico et al, 2005) comprise dominant pure and impure marbles and calc-silicate rocks, interlayered with pelitic schists, paragneisses, amphibolites and minor amphibolitic schists (Williams et al, 1971;Findlay et al, 1984). These metasedimentary rocks are intruded by pre-, syn-, and postkinematic granitic and subordinate dioritic to gabbroic plutons, plugs, dykes and sills of the 510 to 480 Ma old Granite Harbor Intrusive Complex (Gunn and Warren, 1962;Allibone et al, 1993a).…”

The Fontaine Pluton: An early Ross Orogeny calc‐alkaline gabbro from southern Victoria Land, Antarctica

“…The Skelton Group and associated orthogneisses are intruded by relatively undeformed plutons that range in age from the late Proterozoic to the Ordovician (Smillie 1992;Allibone etal. 1993a,b;Cox 1993;Encarnacion & Grunow 1996;Cox et al 2000;Cook & Craw 2001,2002Allibone & Wysoczanski 2002;Mellish et al 2002;Read et al 2002).…”

“…1). The oldest rocks exposed in southern Victoria Land consist of multiply deformed, greenschist to upper amphibolite facies metasediments of the Skelton Group and intercalated orthogneisses (Gunn & Warren 1962;Allibone 1992;Cox 1992;Cook 1997;Cook & Craw 2001, 2002. The Skelton Group and associated orthogneisses are intruded by relatively undeformed plutons that range in age from the late Proterozoic to the Ordovician (Smillie 1992;Allibone etal.…”