Abstract
Zircon SIMS U-Pb dating of the Poshi, Hongshishan, Bijiashan, and Huangshan Ni-Cu-bearing and Xiangshan Ni-Cu-Ti-Fe-bearing mafic-ultramafic intrusions in the Eastern Tianshan and Beishan Rift yields a relatively restricted range of 278.6 Ma to 284.0 Ma. The histogram of compiled age data of basalts in the Tarim Basin and mafic-ultramafic intrusions in the Eastern Tianshan and Beishan Rift has a peak of 280 Ma, which probably represents the time of mantle plume activity. The basalts have lower εNd(t) values in the range of -9.2 ~ -1.7 and Mg# of <50, and higher TiO2 contents (>2 wt.%), indicating that they were generated directly from a peripheral zone of the mantle plume by low degree of melting. The mafic-ultramafic intrusions have higher εNd(t) of -1.3~11.2 and Mg# of 33~90, and lower TiO 2 < 1.8 weight percent, suggesting that their parental magmas were produced from lithospheric mantle source by high degree of melting due to higher temperature of the mantle plume head. A possible mantle plume model beneath lithospheric mantle of the Tarim Basin, Tianshan and Beishan and its spatial framework is suggested.
Original language | English |
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Pages (from-to) | 237-260 |
Number of pages | 24 |
Journal | American Journal of Science |
Volume | 311 |
Issue number | 3 |
DOIs | |
Publication status | Published - Mar 2011 |
Keywords
- Beishan Rift
- Eastern Tianshan
- Large igneous province
- Mantle plume
- Ni-Cu-bearing mafic-ultramafic intrusion
- Tarim Basin