| 西天山松湖铁矿区火山岩地球化学特征、成岩时代及其地质意义 |
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| 关键词:Western Tianshan Mountains Songhu iron deposit volcanic rocks geochemistry geochronology petrogenesis |
| 基金项目:中国地质调查局地质矿产评价专项(编号: 12120114007501; 12120113044000); 中央高校基本科研业务费专项基金(编号: 2013G1271096; 2014G1271066); 国家自然科学基金项目(编号: 41273033) |
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| Geochemistry and Geochronology of the Volcanic Rocks in the Songhu Iron Deposit of Western Tianshan Mountains and Their Geological Significance |
| Located at the northwest edge of Yili plate in Western Tianshan Mountains, Xinjiang, the Awulale metallogenic belt is one of the significant polymetallic iron, copper and gold belts discovered in recent years. The Songhu iron deposit is one of the volcanic type iron deposits in the western part of the belt and is hosted in the 2nd member of the Carboniferous Dahalajunshan Group. This paper focused on the petrology, petrography, geochemistry and geochronology of the volcanic rocks exposed in the ore district and tried to constrain their tectonic settings and petrogenesis. Some conclusions have been reached: (1) These volcanic rocks mainly consist of andesite and dacite, with minor rhyolite and volcaniclastic rocks, and belong to the calc-alkaline series. (2) The U-Pb age of zircons in the andesite is (343.2±2) Ma (MSWD=1.8), suggesting the Visean Age. (3) Trace element patterns show enrichment of LILE (Rb, Ba, Th, K etc.) and LREE, and depletion of HFSE (Nb, Ta, Ti). These characteristics suggest that these volcanic rocks might have been formed in the active continental margin arc and produced by cognate magma. (4) These volcanic rocks are characterized by relatively high εNd(t) values (+2.09 ~ +3.39) and high initial 87Sr/86Sr ratios (0.7056~0.7060). The Nd-Sr isotopic characteristics indicate that their magma source was the roof of continental arc crust near the Moho surface. |
| JING De-long,WANG Bang-yao,ZHANG Bo,JIANG Chang-yi,XIA Ming-zhe,LI Yong-jun,REN Yi.2015.Geochemistry and Geochronology of the Volcanic Rocks in the Songhu Iron Deposit of Western Tianshan Mountains and Their Geological Significance[J].Acta Geoscientica Sinica,36(6):729-741. |
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