Cenozoic Tectonics in the Yule Bay Area:  An Alternative Approach to the Structural Evolution of the Enigmatic Surgeon Island Block (Northern Victoria Land, Antarctica)

A.L. Läufer¹*, F. Rossetti² & N.W. Roland³

¹Johann Wolfgang Goethe-Universität, Geologisch-Paläontologisches Institut, Senckenberganlage 32-34,
60054 Frankfurt a.M. - Germany
²Dipartimento di Scienze Geologiche, Universitá “Roma Tre”, Largo S. L. Murialdo 1, 00146 Roma - Italy
³Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Stilleweg 2, 30655 Hannover – Germany


Received 24 January 2003; accepted in revised form 30 October 2003
 

Abstract - Structural investigations were performed on Surgeon Island, Thala Island, and Unger Island in the Yule Bay area, offshore northern Victoria Land (Antarctica). Our data document a brittle to semi-brittle overprint on the early Palaeozoic gneissic rocks of Surgeon Island and on the homogeneously textured Devonian-Carboniferous Admiralty Intrusives of Thala Island. Such a brittle overprint is associated with E-W to ESE-WNW trending, steeply dipping right-lateral transpressive fault zones, globally arranged in positive flower structure-like arrays. Strong brittle to semi-brittle shear localisation particularly occurs along the major reverse fault zones detected on Surgeon Island with S-C fabric development and associated large quartz-chlorite-sericite mobilisation. A reverse shear zone with comparable kinematics is also present at Unger Island. We correlate the observed deformation pattern to the crustal-scale right-lateral shear systems that cut through Victoria Land during the Cenozoic. Surgeon Island is tentatively interpreted as a strongly sheared, transpressive tectonic block embedded within a branch of the WNW-ESE trending Cenozoic Cape Adare Fault Zone, located offshore the northern Victoria Land coast line.


 
*Corresponding author (laeufer@em.uni-frankfurt.de)