Późnotrzeciorzȩdowe bazalty w strefie uskoku Dien Bien Phu w NW Wietnamie: implikacje tektoniczne wynikaja̧ce z badań petrologicznych

Translated title of the contribution: Late Tertiary basalts in the Dien Bien Phu Basin, NW Vietnam: Some tectonic implications of petrological studies

Ewa Koszowska, Anna Wolska, Witold Zuchiewicz, Nguyen Quoc Cuong, Zoltan Pécskay

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Basalts encountered in the Dien Bien Phu pull-apart basin in NW Vietnam, associated with the presently sinistral Dien Bien Phu fault, are quartz tholeiites that have been K-Ar-dated to 5.4-5.2 Ma. They consist of plagioclase, orthopyroxene and olivine phenocrysts, and fine-grained crystalline matrix (olivine, plagioclase, clinopyroxene). The Dien Bien Phu basalts contain not only ultramafic and mafic (pyroxenites, dunites, gobbros), but also wallrock xenoliths (sillimanite/mullite+ Mg-Fe spinels). The occurrence of wallrock xenoliths is indicative of the contamination in wallrock material during the ascent of basaltic magma. The Dien Bien Phu basalts are characterized by selective increase in ratios of such incompatible elements as K, Rb and Th, what can be considered as an evidence of metasomatic modification of residual melt composition (rims of K-feldspar around plagioclase phenocrysts and small K-feldspar grains occurring in the interstices within the matrix).

Translated title of the contributionLate Tertiary basalts in the Dien Bien Phu Basin, NW Vietnam: Some tectonic implications of petrological studies
Original languagePolish
Pages (from-to)841-850
Number of pages10
JournalPrzeglad Geologiczny
Volume51
Issue number10
Publication statusPublished - Oct 1 2003

Keywords

  • Dien Bien Phu fault
  • Geochemistry
  • Late Tertiary
  • Petrography
  • Vietnam
  • Within-plate basalts

ASJC Scopus subject areas

  • Geology
  • Atmospheric Science

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