The upper mantle beneath Patagonia, Argentina, documented by xenoliths from alkali basalts

Ernesto A Bjerg, Theodoros Ntaflos, Gero Kurat, G Dobosi, Carlos Horacio Labudia

    Veröffentlichungen: Beitrag in FachzeitschriftArtikelPeer Reviewed


    Mantle xenoliths in alkali basaltic lavas (with ocean-island basalt chemical signatures) and cinder cones occur in several areas of Patagonia. A representative suite of mantle xenoliths was collected in the region between latitudes 40° and 52°S and longitudes 67° and 71°W in the RiŽo Negro, Chubut, and Santa Cruz provinces, Argentina. Mantle xenoliths in Patagonia display distinguishing peculiarities compared with those of other worldwide occurrences. The lithospheric mantle beneath Patagonia, as inferred from chemical variation diagrams, has experienced only minor melt extractions in the garnet peridotite field and more extensive melt extractions in the spinel lherzolite field. Variably intensive cryptic and modal metasomatism affected the lithospheric mantle in this region. Textural evidence shows that the mantle is moderately to strongly tectonized and recrystallized on both the local and the regional scale, with an overall predominance of deformed textural types. Mineral equilibrium indicates a strongly elevated geotherm similar to the southeast Australia and oceanic geotherms, which is not normal for a continental intraplate tectonic setting. Therefore, the properties of the Patagonian samples are probably related to the presence of rising mantle plume(s) in an extensional tectonic setting. Œ 2004 Published by Elsevier Ltd.
    Seiten (von - bis)125-145
    FachzeitschriftJournal of South American Earth Sciences
    PublikationsstatusVeröffentlicht - 2005

    ÖFOS 2012

    • 1051 Geologie, Mineralogie