Volume 85, Issue 1 pp. 116-129
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Geochemical Characteristics and Geological Significance of Early Permian Baya'ertuhushuo Gabbro in South Great Xing'an Range

LIU Jianfeng

Corresponding Author

LIU Jianfeng

College of Earth Sciences, Jilin University, Changchun 130061, China

Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China

Corresponding author. E-mail: [email protected], [email protected]Search for more papers by this author
CHI Xiaoguo

Corresponding Author

CHI Xiaoguo

College of Earth Sciences, Jilin University, Changchun 130061, China

Corresponding author. E-mail: [email protected], [email protected]Search for more papers by this author
ZHAO Zhi

ZHAO Zhi

College of Earth Sciences, Jilin University, Changchun 130061, China

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ZHANG Xingzhou

ZHANG Xingzhou

College of Earth Sciences, Jilin University, Changchun 130061, China

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MA Zhihong

MA Zhihong

College of Earth Sciences, Jilin University, Changchun 130061, China

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WANG Tiefu

WANG Tiefu

The Center of Test and Science Experiment, Jilin University, Changchun 130026, China

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HU Zhaochu

HU Zhaochu

State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074, China

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First published: 31 January 2011
Citations: 11

Abstract:

Field geological investigation and geochemical analysis are carried out on Baya'ertuhushuo Gabbro in South Great Xing'an Range. Field investigation reveals that the gabbro is a magmatic intrusion rather than a component of an ophiolite suite as previously thought. Zircon laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS) U-Pb dating indicates the gabbro was formed in 274–275 Ma, just as the widespread volcanic rocks of Dashizhai Formation (P1d), monzogranites and miarolitic alkali-feldspar granites in the study area. The gabbro has SiO2 content between 47.23 wt% and 50.17 wt%, high MgO and FeOT contents of 6.95–11.29 wt% and 7.32–12.24 wt%, respectively, and it belongs to low-K tholeiitic series in the SiO2-K2O diagram. The Chondrite-normalized rare earth element (REE) patterns and primitive mantle-normalized spider diagrams of the gabbro are similar to those of Normal Mid-Ocean Ridge Basalt (N-MORB) except for the enrichment of large ion lithophile elements (LILE), such as Rb, Ba and K. In trace element tectonic discriminative diagrams, the samples are mainly plotted in the N-MORB field, and Zircon in situ Lu-Hf isotopic analysis also indicates the gabbro originated from depleted mantle. Through synthetic studies of the geochemical characteristics and petrogenesis of Baya'ertuhushuo gabbro, volcanic rocks of Dashizhai Formation and granitoids in the area, it is suggested that the early Permian magmatism in the Xilinhot-Xiwuqi area formed in the tectonic setting of asthenosphere upwelling, which was caused by breaking-off of the subducted Paleo-Asian Ocean slab.

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