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A revised geochemical grouping of Gondwana LIP: distinctive sources and processes at the Weddell and Limpopo triple junctions

Luttinen, A.V.; Leat, P.T.. 2007 A revised geochemical grouping of Gondwana LIP: distinctive sources and processes at the Weddell and Limpopo triple junctions. In: Cooper, A.K.; Raymond, C.R.; ISAES Editorial Team, ., (eds.) Antarctica: a keystone in a changing world. Online proceedings of the 10th International Symposium on Antarctic Earth Sciences, Santa Barbara, California, August 26 - September 1, 2007. U.S. Geological Survey, National Academy Press, 4pp. (U.S. Geological Survey Open-File Report, 2007-1047, Exten).

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Abstract/Summary

The magma types belonging to the Gondwana large igneous province can be divided into two categories based on, respectively, their primitive mantle-like and fractionated Sm/Yb and Sr/Zr values, different Sr and Nd isotopic trends, and geographic affinity to the Weddell and Limpopo triple junctions. In the new grouping, the Ferrar magmas, the Karoo Central Area magmas, and the Kirwanveggen-Sembberget magmas from Dronning Maud Land are viewed as three major magmatic lineages generated at the Weddell triple junction. These Weddell group magmas were produced by voluminous low-pressure partial melting of possibly subduction-modified upper mantle and tended to be laterally transported over long distances. The Limpopo group magmas include the Karoo high-Ti magma types and various low- Ti types from Lebombo, Vestfjella, and Heimefrontfjella. They represent magmas that were produced at high pressure from an eclogite-bearing mantle source below the Kaapvaal craton. The distribution of the Limpopo group magmas was mainly confined within the rift valleys of the Limpopo triple junction. The chemically distinctive magma types probably reflect heterogeneities in the Weddell and Limpopo magma sources and lithospheric level differentiation within Archean (Limpopo group) and younger lithospheric terranes.

Item Type: Publication - Book Section
Programmes: BAS Programmes > Global Science in the Antarctic Context (2005-2009) > Long-Term Monitoring and Survey – Geosciences Division
NORA Subject Terms: Earth Sciences
Date made live: 02 Nov 2011 12:39
URI: http://nora.nerc.ac.uk/id/eprint/15760

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