Role of Pyroxenite Mantle in the Formation of the Mesozoic Karoo Plume Melts: Evidence from the Western Queen Maud Land, East Antarctica

N. M. Sushchevskaya, A. V. Sobolev, G. L. Leitchenkov, V. G. Batanova, B. V. Belyatsky, A. V. Zhilkina

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Petrological and geochemical study of basalts and dolerites in East Antarctica, the formation of which is explained by the Karoo plume impact on the Queen Maud Land, revealed the presence of high-magnesium magmas, Fe-rich and depleted in incompatible elements, among the geochemically diverse magmas. Such high-Mg ferropicrites are scarce in other plume-related igneous provinces and their genesis is related to melting of a peculiar pyroxenite mantle source. These rocks were found only in the Ahlmannryggen and Vestfjella massifs in Antarctica and in the Letabo province in South Africa, correspond to the central part of the plume and likely the earliest eruptions. The studied dolerites are close to the parental melts. They have a relatively smoothed lithophile element pattern (from Th to Er), the lowered content of most compatible elements (Y, Yb, Lu), as well as the low 206Pb/204Pb = 17.33–17.37 and moderately radiogenic neodymium composition with 143Nd/144Nd from 0.51249 to 0.51259, which indicate a relatively old age of the pyroxenite component. All high-Ti basalts related to the Karoo–Maud plume point to the presence of this component in their compositions, but its proportion could significantly vary.

Original languageEnglish
Pages (from-to)357-376
Number of pages20
JournalGeochemistry International
Volume59
Issue number4
DOIs
StatePublished - 16 Apr 2021

Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

Keywords

  • Ahlmannryggen
  • isotope signatures
  • Karoo plume
  • lithophile element geochemistry
  • olivines
  • picritic magmas
  • Queen Maud Land

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