Geochronology of the gabbro-mafic microgranular enclaves-granite associations in the Gejiu district, Yunnan province and their geodynamic significance

Cheng, Yanbo, and Mao, Jingwen (2012) Geochronology of the gabbro-mafic microgranular enclaves-granite associations in the Gejiu district, Yunnan province and their geodynamic significance. Acta Geologica Sinica, 86 (3). pp. 748-761.

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Abstract

Many igneous rocks distribute in Gejiu tin polymetallic ore-field at Yunnan province, rocks including basalt, gabbro, mafic microgranular enclaves, granites (porphyritic granite and equigranular granite) and akaline rocks. The ages of the granites and akaline rocks which are considered to have genetic connecting with the mineralization have been comfirmed, but the gabbro-mafic microgranular enclaves-granite assemblage's ages are still unknown. By means of LA-ICP-MS zircon U-Pb dating, the data of Shenxianshui equigranular granite, the mafic microgranular enclave in Jiasha area, the host rock of the mafic microgranular enclaves and the Jiasha gabbro are around ~80 Ma. Besides the above mentioned data, a group of new ages at ~30 Ma were discovered in this study, which is from gabbro and mafic microgranular enclaves. Based on the previous data and the new data gained this time, we suggest the major geochronology framework of the magmatism and mineralization events in Gejiu area is ~80 Ma, which is consistent with the Late Cretaceous magmatism and mineralization events in the whole southeast Yunnan and west Guangxi area and they were suggested to belong to the same geotectonic setting in late Yenshannian. And the new ages of the ~30 Ma obtained in this study is considered to represent a responding to the complicate tectonic evolution history of the Tibetan orogenic events in Cenozoic.

Item ID: 40109
Item Type: Article (Research - C1)
ISSN: 1755-6724
Keywords: gabbro; granite; mafic microgranular enclaves; geochronology; geodynamic setting; Gejiu
Funders: National Science Foundation of China (NSFC), Special Research Funding for the Public Benefits (SRFPB) Sponsored by MLR of China, Research Program of Yunnan Tin Group (RPYTG), Geological Investigation Program by CGS (CGS), Fundamental Research Funds for the Central Universities (FRFCU)
Projects and Grants: NSFC 40930419, SRFPB 200911007-12, RPYTG 2010-04A, CGS 1212011120994, FRFCU 2-9-2010-21
Date Deposited: 20 Aug 2015 02:36
FoR Codes: 04 EARTH SCIENCES > 0403 Geology > 040307 Ore Deposit Petrology @ 100%
SEO Codes: 84 MINERAL RESOURCES (excl. Energy Resources) > 8401 Mineral Exploration > 840199 Mineral Exploration not elsewhere classified @ 100%
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