Bjornnutane and Sembberget basalt lavas and the geochemical provinciality of Karoo magmatism in western Dronning Maud Land, Antarctica

作者：Luttinen Arto V^*; Leat Philip T; Furnes Harald

来源：Journal of Volcanology and Geothermal Research, 2010, 198(1-2): 1-18.

DOI：10.1016/j.jvolgeores.2010.07.011

• flood basalt
• Jurassic
• petrogenesis
• mantle source
• eclogite

Geochemical provinciality of the Karoo continental flood basalt (CFB) province is complicated by the great diversity of magma types Our geochemical and Nd and Sr isotopic data indicate derivation of Karoo-related low Ti CFBs of Bjornnutane and Sembberget Dronning Maud Land Antarctica from different magma plumbing systems that were typified by generation of magma subtypes largely by vanable degrees of fractional crystallization and crustal contamination We associate these plumbing systems with different mantle sources and propose that the Karoo CFBs of Dronning Maud Land can be grouped into two provinces derived from these sources The Grunehogna province magmas include high Ti and some low-Ti magma types have high (Sm/Yb)(N) (>2) are enriched in Sr and Eu and show wide range of initial epsilon Nd (+ 9 to 16) Grunehogna province magmas dominate at Bjornnutane Vestfjella and Ahlmannryggen The Maud province magmas show low-Ti affinity have low (Sm/Yb)N (<2) lack Sr and Eu enrichment and have relatively narrow range of initial epsilon Nd (+3 to 4) Maud province magmas are restricted to Sembberget Kirwanveggen and the Utpostane gabbros in Vestfjella The enrichment of Sr and Eu and the depletion of heavy rare earth elements in Grunehogna province magmas and specifically geochemical indications of recycled oceanic crust in the least-contaminated high Ti and low-Ti basalts and picntes lend support to a recycled source component Grunehogna magmas are ascribed to partial melting of eclogite-bearing asthenosphenc mantle source at depth below the Grunehogna craton and contamination of the magmas with lithosphenc mantle (high Ti types) and crust (low-Ti types) The Maud province magmas can be ascribed to relatively low-pressure partial melting probably of a lithosphenc mantle source within the zone of rifted lithosphere associated with the Weddell triple junction and lateral flow of magmas to present outcrops overlying thick Maud Belt lithosphere Geochemical comparison with Karoo CFBs in southern Africa implies a broadl

• 出版日期2010-12-1
• 单位British Antarctic Survey