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Geoscience ›› 2023, Vol. 37 ›› Issue (03): 573-585.DOI: 10.19657/j.geoscience.1000-8527.2022.022

• Petrology and Petrogeochemistry • Previous Articles     Next Articles

Record of Mesozoic Collision Orogeny on the Eastern Section of the West Kunlun Orogen: Evidence from Geochronology and Geochemistry of the Triassic Wenquan-Shenglidaban Granitic Intrusions, Xinjiang

LU Hao(), LIU Huan, HU Feng(), WANG Haibo, WANG Chao, KONG Xiangchao   

  1. Shandong No.3 Exploration Institute of Geology and Mineral Resources, Yantai, Shandong 264004, China
  • Received:2021-07-11 Revised:2022-03-26 Online:2023-06-10 Published:2023-07-20

Abstract:

Many Triassic intrusive rocks are emplaced in Wenquan-Shenglidaban area in the eastern section of the West Kunlun orogen. The lithology mainly includes medium-/fine-grained monzogranite, which records the Mesozoic tectonic evolution of the orogen and provides chronological constraints for the metallogenic age of gold, mercury, antimony and other metals in this area. In this study, detailed analyses on the petrology, whole-rock chemistry and zircon U-Pb geochronology of the Lower Triassic Adamupa lower series granites are presented. The results show that the Wenquan-Shenglidaban granite was emplaced at (203.3±1.4) Ma, indicating a product of the Late Triassic magmatic activity. The rocks have SiO2, Na2O, K2O and A/CNK of 74.41%-76.78%, 2.70%-3.81%, 3.93%-5.01% and 1.00-1.25, respectively, indicating that the granites are peraluminous high-K calc-alkaline with low total rare earth element contents. The granites are rich in light rare earth elements and negative Eu anomaly (δEu=0.39), and are relatively rich in Rb, Th and U, but depleted in Ba, Nb, Sr, and Ti. This indicates that the granites are crustal-derived S-type. Combined with the regional tectonic evolution, the Atamupa granite was likely formed in the post-orogenic stage. It is probably a post-collisional granite sourced by the partial melting of the subducted metamorphic clastic rocks into the lower crust. The resulted magma then ascended and emplaced at upper crust and the granites was formed.

Key words: S-type granite, zircon U-Pb dating, petrogeochemistry, Wenquan-Shenglidaban, West Kunlun

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