Geochemical characteristics and geological implication of adamellite in Yazigou area of Qimantag, Qinghai Province
WANG Panxi1,2,3, WANG Zhenning1,2
1. Zhengzhou Institute of Multipurpose Utilization of Mineral Resources, Chinese Academy of Geological Sciences, Zhengzhou 450006, China; 2. National Research Center of Multipurpose Utilization of Non-metallic Mineral Resources, Zhengzhou 450006, China; 3. Northwestern China Center for Geosience Innovation, Xi’an 710054, China
Abstract：The metal deposits, related to acid-intermediate magmatic intrusive activities, have been discovered in Qimantag area, and the area has become the most important and favorable prospecting Fe-Cu-Pb-Zn multimetallic metallogenic belt. Through the petrography and rock geochemistry study of adamellite in Yazigou area, the authors discussed its petrogenesis, tectonic setting and relation with mineralization. The results show that Yazigou adamellite has the typical features of high silicic, potassium and alkali contents and low aluminium, calcium, magnesium and iron contents, and the rocks belong to weakly peraluminous and high-kalium calc-alkaline rock series. The average value of ∑REE is 181.24×10-6 and the values of δEu are 0.07~0.11,with the average value of 0.09, indicating a remarkable Eu depletion. The rare earth patterns of rocks/chondrite show slightly right-dipping V-type curves, and light and heavy rare earth fractionation is not obvious. The rocks are significantly enriched in large ion lithophile elements of Rb, K, and active incompatible elements of U, Th , Pb, while high field strength elements of Nb, Ta, P,Ti, and large ion lithophile elements of Ba and Sr are relatively depleted. The adamellite of Yazigou region belongs to A2-type granite, which was formed in post-collision stage of collisional orogenic setting. This area has many porphyry-type copper molybdenum and skarn-type lead-zinc ore occurrences, so the prospecting work should be emphasized in adamellite of Late Triassic epoch.
王盘喜, 王振宁. 青海祁漫塔格鸭子沟地区二长花岗岩地球化学特征及地质意义[J]. 中国地质调查, 2020, 7(1): 38-46.
WANG Panxi, WANG Zhenning. Geochemical characteristics and geological implication of adamellite in Yazigou area of Qimantag, Qinghai Province. , 2020, 7(1): 38-46.
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