Zircon Geochronology and Trace Element Geochemistry from the Xiaozhen Copper Deposit, North Daba Mountain: Constraints on Albitites Petrogenesis |
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作者姓名: | WANG Gang WANG Zongqi ZHANG Yingli and WANG Kunming |
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作者单位: | 1 School of Earth Sciences and Resources,China University of Geosciences, Beijing 100083, China
2 Institute of Mineral Resources,Chinese Academy of Geological Sciences, Beijing 100037, China |
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基金项目: | This work is supported by the fundamental research funds for central public welfare research institutes (grant: K1313), National Natural Science Foundation of China (grant: 41302080) and the geological survey project of China (grant: 1212011121091). |
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摘 要: | Albitite often accompanies with various metal and gem mineral deposits and a large number of occurrences have been reported globally, including the South Qinling orogen, China. The Xiaozhen copper deposit is a typical deposit in the North Daba Mountain area of the South Qinling orogen whose distribution is controlled by albitite veins and fractures. As there are few studies on the petrogenesis of albitite in Xiaozhen copper deposit, this paper focuses on the petrogenesis of albitite and its mineralization age. Detailed fieldwork and mineral microscopic observations initially suggest that albitite from the Xiaozhen copper deposit is igneous in origin. Further zircon trace element geochemistry studies indicate that these zircons have high Th/U ratios(0.5), low La content, high(Sm/La)N and Ce/Ce*values, and a strong negative Eu anomaly, which are commonly seen in magmatic zircons. The chondrite–normalized rare earth element(REE) patterns are consistent with magmatic zircons from throughout the world, and they fall within or near the field of magmatic zircons on discriminant diagrams. The calculated average apparent Ti–in–zircon temperature for young zircons is 780°C, consistent with magmatic zircon crystallization temperatures. Therefore, zircon geochemistry indicates that the albitite origin is magmatic. SIMS U–Pb dating on nine magmatic zircons yielded a concordia age of 154.8±2.2 Ma, which represents the formation of albitite and the metallogenic age. More importantly, it is consistent with the ages of Yanshanian magmatism and metallogenesis in the South Qinling orogen, so formation of the Xiaozhen copper deposit may be a closely related geological event.
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关 键 词: | 微量元素地球化学 锆石年代学 岩浆成因 铜矿 北大巴山 秦岭造山带 成矿时代 化学研究 |
收稿时间: | 2013/7/26 0:00:00 |
修稿时间: | 9/8/2013 12:00:00 AM |
Zircon Geochronology and Trace Element Geochemistry from the Xiaozhen Copper Deposit,North Daba Mountain: Constraints on Albitites Petrogenesis |
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Authors: | WANG Gang WANG Zongqi ZHANG Yingli WANG Kunming |
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Institution: | [1]School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China [2]Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China |
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Abstract: | Albitite often accompanies with various metal and gem mineral deposits and a large number of occurrences have been reported globally, including the South Qinling orogen, China. The Xiaozhen copper deposit is a typical deposit in the North Daba Mountain area of the South Qinling orogen whose distribution is controlled by albitite veins and fractures. As there are few studies on the petrogenesis of albitite in Xiaozhen copper deposit, this paper focuses on the petrogenesis of albitite and its mineralization age. Detailed fieldwork and mineral microscopic observations initially suggest that albitite from the Xiaozhen copper deposit is igneous in origin. Further zircon trace element geochemistry studies indicate that these zircons have high Th/U ratios (>0.5), low La content, high (Sm/La)N and Ce/Ce* values, and a strong negative Eu anomaly, which are commonly seen in magmatic zircons. The chondrite–normalized rare earth element (REE) patterns are consistent with magmatic zircons from throughout the world, and they fall within or near the field of magmatic zircons on discriminant diagrams. The calculated average apparent Ti–in–zircon temperature for young zircons is 780°C, consistent with magmatic zircon crystallization temperatures. Therefore, zircon geochemistry indicates that the albitite origin is magmatic. SIMS U–Pb dating on nine magmatic zircons yielded a concordia age of 154.8±2.2 Ma, which represents the formation of albitite and the metallogenic age. More importantly, it is consistent with the ages of Yanshanian magmatism and metallogenesis in the South Qinling orogen, so formation of the Xiaozhen copper deposit may be a closely related geological event. |
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Keywords: | Albitite petrogenesis SIMS zircon geochronology zircon trace element geochemistry Xiaozhen copper deposit North Daba Mountain |
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