Modified Gulf of California model for South Georgia,north Scotia Ridge, and implications for the Rocas Verdes back-arc basin, southern Andes

Research Article| June 01, 1990 Modified Gulf of California model for South Georgia,north Scotia Ridge, and implications for the Rocas Verdes back-arc basin, southern Andes T. Alabaster; T. Alabaster 1British Antarctic Survey, Natural Environment Research Council, Madingley Road, Cambridge CB3 0ET, England Search for other works by this author on: GSW Google Scholar B. C. Storey B. C. Storey 1British Antarctic Survey, Natural Environment Research Council, Madingley Road, Cambridge CB3 0ET, England Search for other works by this author on: GSW Google Scholar Author and Article Information T. Alabaster 1British Antarctic Survey, Natural Environment Research Council, Madingley Road, Cambridge CB3 0ET, England B. C. Storey 1British Antarctic Survey, Natural Environment Research Council, Madingley Road, Cambridge CB3 0ET, England Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1990) 18 (6): 497–500. https://doi.org/10.1130/0091-7613(1990)018<0497:MGOCMF>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation T. Alabaster, B. C. Storey; Modified Gulf of California model for South Georgia,north Scotia Ridge, and implications for the Rocas Verdes back-arc basin, southern Andes. Geology 1990;; 18 (6): 497–500. doi: https://doi.org/10.1130/0091-7613(1990)018<0497:MGOCMF>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract New field mapping and an integrated trace element and Nd isotopic study have been undertaken on the Jurassic-Cretaceous Larsen Harbour Complex on the island of South Georgia, recognized as a displaced part of the southern Andes ensialic, autochthonous Rocas Verdes marginal basin. Five basalt groups (Groups I-V) are identified from trace element data; initial Nd isotopic compositions suggest that they are derived from only two sources. Magmas produced during early stages of continental lithospheric attenuation (Groups I-III) were derived by varying degrees of partial melting and fractional crystallization from a large ion lithophile element (LILE)-enriched, low-ϵNd mantle source relative to normal (N)-type mid-ocean ridge basalt (MORB). Magmas produced during later stages of rifting (Groups IV and V) were, however, derived from a high-ϵNd asthenospheric mantle source similar to N-type MORB, unaffected by earlier LILE enrichment. Our data do not concur with previous suggestions that the Larsen Harbour Complex and, by implication, the Rocas Verdes formed in a supra-subduction-zone setting. On the basis of geologic and geochemical evidence, we favor basin formation along an oblique-slip margin akin to that of the Gulf of California. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.