Lyell Collection
Geological Society, London, Special Publications
Lyell Centre  |   Lyell Collection  |   Subscriptions   |   Geological Society  |   Email alerts  |   Online bookshop  |   Help

Keywords:
Author:
Advanced search>>
This Article
Right arrow Full Text (PDF)
Right arrow References
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Storey, B. C.
Right arrow Articles by Macdonald, D. I. M.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation
Geological Society, London, Special Publications; 1984; v. 16; p. 207-218;
DOI: 10.1144/GSL.SP.1984.016.01.16
© 1984 Geological Society of London

South America & Antarctica

Processes of formation and filling of a Mesozoic back-arc basin on the island of South Georgia

B. C. Storey & D. I. M. Macdonald

British Antarctic Survey, Natural Environment Research Council, Madingley Road, Cambridge CB3 0ET, U.K.
Sedimentology Branch, BP Exploration Co. Ltd, Britannic House West, London EC2Y 9BU, U.K.

South Georgia contains a diverse suite of rocks representing different stages in the development of a back-arc basin on the Gondwana margin during the Mesozoic. Basin formation initially involved intrusion of large gabbroic plutons into deformed paragneisses and calc-alkaline rocks of a magmatic arc, and then extension of this crust by dyke emplacement. Partial melting of the metasediments formed a migmatitic aureole around the basic rocks. Rifting of this thinned continental crust led to the emplacement of mafic crust composed of lavas, dykes and plutonic gabbros with oceanic crustal characteristics. On an upper slope marginal to the arc, the mafic crust is overlain by a thinly bedded sequence of tuffs and mudstones deposited by turbidity currents. Overlying andesitic volcaniclastic rudites, deposited by debris flows, represent a major channel-fill sequence. The basin was filled by thick sequences of both arc-derived volcaniclastic sandstones and silicic detritus with a continental provenance. The volcaniclastic sediments form a fault-controlled aggrading system, deposited by high- and low-density turbidity currents in an elongate basin.