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 language | English |
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Pages (from-to) | 145-152 |
Number of pages | 8 |
Journal | Gondwana Research |
Volume | 17 |
Issue number | 1 |
Early online date | 2 Jun 2009 |
DOIs | |
Publication status | Published - Jan 2010 |
Externally published | Yes |
Bibliographical note
We thank Zhang Qi and Wang Qiang for their constructive suggestions. We are grateful to two anonymous reviewers whose critical reviews are very helpful in improving the manuscript.Keywords
- Cu-Au mineralization
- Dike
- Junggar
- Ridge subduction
- Sanukitoid