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Lithospheric mantle domains beneath Antarctica

Leat, P.T.; Dean, A.A.; Millar, I.L.; Kelley, S.P.; Vaughan, A.P.M.; Riley, T.R.. 2005 Lithospheric mantle domains beneath Antarctica. In: Vaughan, A.P.M.; Leat, P.T.; Pankhurst, R.J., (eds.) Terrane processes at the margins of Gondwana. London, UK, Geological Society of London, 359-380. (Geological Society of London special publication, 246).

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Abstract/Summary

The chemistry of mafic volcanic rocks and minor intrusions erupted on continents can be used to define sub-continental asthenospheric and lithospheric mantle sources. Data have been collated from Antarctica and the Falkland Islands (adjacent in Gondwana) in order to identify lithospheric mantle sources beneath the continent. The lithosphere-derived magmas include lamproitic and some lamprophyric rocks and end-members in basaltic suites that are interpreted as mixtures of magmas from lithospheric and asthenospheric sources. The lithosphere-derived mafic rocks from Archaean to Middle Proterozoic cratonic and circumcratonic areas of East Antarctica have time-corrected εNd values of −20 to −3. This demands isolation of the LREE-enriched sources within pockets of stable sub-cratonic lithosphere for more than 1 Ga, consistent with the lithosphere thickness up to 250 km imaged by seismic tomography. In contrast, lithosphere-derived mafic rocks from Middle Proterozoic to Early Palaeozoic areas of West Antarctica, Victoria Land and the Falkland Islands that formed the Gondwana continental margin, have time-corrected εNd values of −3.6 to +3.5, implying more recent isolation from asthenosphere. In terms of mantle reservoirs, cratonic and circumcratonic areas trend toward EMI, with EMII possibly being a minor component. In contrast, Gondwana margin areas trend toward EMII, with EMI being, at most, a very minor component.

Item Type: Publication - Book Section
Digital Object Identifier (DOI): 10.1144/GSL.SP.2005.246.01.15
Programmes: BGS Programmes > NERC Isotope Geoscience Laboratory
BAS Programmes > Antarctic Science in the Global Context (2000-2005) > Antarctica in the Dynamic Global Plate System
ISBN: 1862391793
Date made live: 27 Apr 2012 10:59
URI: http://nora.nerc.ac.uk/id/eprint/17894

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