Earth Science Frontiers ›› 2018, Vol. 25 ›› Issue (5): 96-118.DOI: 10.13745/j.esf.sf.2018.4.2

Previous Articles     Next Articles

Geochemistry, geochronology and oxygen fugacity of volcanic and intrusive rocks from the Laoshankou Fe-Cu-Au deposit in the northern margin of East Junggar, NW China.

LIANG Pei,CHEN Huayong,WU Chao,LIU Zhenjiang   

  1. 1. Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
    2. University of Chinese Academy of Sciences, Beijing 100049, China
    3. No.4 Geological Party of the Xinjiang Bureau of Geology and Mineral Exploration and Development, Altay 836500, China
  • Received:2018-02-08 Revised:2018-04-12 Online:2018-09-15 Published:2018-09-15

Abstract: The Laoshankou deposit is an important Fe-Cu-Au deposit in the northern margin of the East Junggar, NW China. LA-ICP-MS U-Pb dating of zircon constrains the timing of crystallization of Ordovician basaltic andesite (~449 Ma), Ordovician andesite (~447 Ma), Devonian volcanic rocks (393376 Ma), monzodiorite (~379 Ma), biotite diorites (~379 Ma), quartz syenites (~376 Ma), fine-grained diorite (~370 Ma), alkali granite (~330 Ma) and coarse-grained diorite porphyry (~310 Ma). Zircon dating indicates three periods of magmatism in Laoshankou: 450440 Ma, ~390370 Ma and 330310 Ma. The magmatism for the first two periods occurred in a subduction-related island arc setting; the magmatism for the last one occurred in a post-collision or inplate extensive setting. Pre-, syn- and post-mineralization volcanic and intrusive rocks are divided based on the Fe-Cu-Au mineralization timing. Syn-mineralization intrusions in Laoshankou have relatively high (Eu/Eu*)N, (Ce/Ce*)N and CeIV/CeIII values of 0.130.86, 1.14445.92 and 33.341165.04, respectively, indicating Fe-Cu-Au mineralization was associated with high oxygen fugacity magmatism.

Key words: northern margin of East Junggar, Laoshankou Fe-Cu-Au deposit, zircon U-Pb geochronology, zircon trace elements, oxygen fugacity

CLC Number: