Late Carboniferous high-Mg dioritic dikes in Western Junggar, NW China : Geochemical features, petrogenesis and tectonic implications

Jiyuan YIN, Chao YUAN*, Min SUN, Xiaoping LONG, Guochun ZHAO, Kenny Powan WONG, Hongyan GENG, Keda CAI

*Corresponding author for this work

Research output: Journal PublicationsJournal Article (refereed)

167 Citations (Scopus)

Abstract

Late Paleozoic High-Mg dioritic dikes widely occur in western Junggar, NW China. Ar-Ar dating on rock chips of the dikes has yielded a plateau age of 321 ± 3 Ma, indicating an early Carboniferous age for the dikes. The dikes are enriched in SiO2 (52-57 wt.%), and characterized by high MgO (5.13-7.41 wt.%), Cr (134-204 ppm), Ni (59-141 ppm), Sr (468-724 ppm) and Ba (316-676 ppm) contents, with geochemical features analogous to those of sanukite of Setouchi volcanic belt, Japan. These dikes contain hornblende and biotite and generally have high Ba/La (27-124) and La/Nb (2.9-4.3) ratios and positive Eu anomalies, consistent with an origin from hydrous partial melting of a mantle source metasomatised by slab-derived component. The occurrence of sanukitic dikes, together with the coeval slab-related adakite in the area, implies that the western Junggar had been affected by hot, subduction-related regime, which gave rise to not only massive magmatism in the late Carboniferous, but also intensive Cu-Au mineralization in the area.

Original languageEnglish
Pages (from-to)145-152
Number of pages8
JournalGondwana Research
Volume17
Issue number1
Early online date2 Jun 2009
DOIs
Publication statusPublished - Jan 2010
Externally publishedYes

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Keywords

  • Cu-Au mineralization
  • Dike
  • Junggar
  • Ridge subduction
  • Sanukitoid

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