| 新疆阿尔泰南缘早—中泥盆世东西部火山岩源区及矿床物质来源差异 |
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| 关键词:Sawusi southern Chinese Altay Early-middle Devonian magma source ore material source association of metallogenic elements |
| 基金项目:国家自然科学基金项目(编号: 40972053; 41230207);国家“十一五”科技支撑计划重大项目二级课题(编号: 2006BAB01A02) |
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| Source Region Differences of Volcanic Host Rocks and Ore Materials between Eastern and Western Altay Mountains during the Early-middle Devonian Period, Xinjiang |
| Voluminous volcanic rocks and numerous sulfide-Fe deposits occur in the southern Chinese Altay Mountains. From the east to the west, metallogenetic associations vary from Pb-Zn through Fe-Pb-Zn to Cu-Zn. This study performed major and trace element, Sr-Nd and zircon Hf-O and sphalerite Pb isotopic analyses of volcanic rocks and ore minerals of the Sawusi Zn-Pb deposit in the east of the southern Chinese Altay. Sulfide Pb and volcanic-rock Sr-Nd isotopic compositions of five representative Fe-sulfide deposits from the east, middle and west of the southern Chinese Altay are compared. Rhyolites of the Early Devonian Kangbutiebao Formation were derived from detrital materials. The latter experienced poly-cycled weathering, erosion, transportation and re-deposition from the Gondwana land through the Tuva-Mongol or from the Caledonian province to the Chinese Altay, which itself was compressed and uplifted at ~400 Ma, and finally delivered to the then trench on the south after erosion from top of the Chinese Altay Mountains. These poly-cycled detrital materials are rich in Zn, possess arc or continental trace element characteristics, and caused high 207Pb/204Pb, 208Pb/204Pb and low 206Pb/204Pb, εNd(t) in the Sawusi and Keketale Pb-Zn deposits in the east of the southern Chinese Altay. The intermediate-basic volcanic eruption resulted in initial enrichment of Fe for the Mengku deposit. The Kelan basin in the middle of the southern Chinese Altay was formed in the ocean continent transition arc or was an interarc basin. In the Kelan basin, intermediate-basic volcanic rock in the middle-lower section and rhyolite in the upper section respectively resulted in Fe and Zn mineralization, whereas Pb mineralization was related to carbonate. These rocks collectively contributed to the formation of the Tiemuerte Fe-Pb-Zn deposit. The Tiemuerte and Mengku deposits exhibit high and variable 206Pb/204Pb, a characteristic of intra-oceanic arc volcanic rocks. The host rock of the Ashele Cu deposit, the west of the southern Chinese Altay, exhibit high εNd(t) and low (87Sr/86Sr)i and Pb isotopic ratios. Mg-rich dacites as derived from the slab fluid-metasomatized mantle wedge resulted in Cu mineralization. |
| LIU Wei,LIU Xiu-jin.2013.Source Region Differences of Volcanic Host Rocks and Ore Materials between Eastern and Western Altay Mountains during the Early-middle Devonian Period, Xinjiang[J].Acta Geoscientica Sinica,34(4):413-424. |
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