| 南天山蛇绿混杂岩中放射虫化石的时代及其构造意义 |
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| 引用本文： | 舒良树,王博,朱文斌.南天山蛇绿混杂岩中放射虫化石的时代及其构造意义[J].地质学报,2007,81(9):1161-1168. |
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| 作者姓名： | 舒良树 王博 朱文斌 |
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| 作者单位： | 南京大学地球科学系,210093 |
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| 基金项目： | 国家地质调查局项目(编号1212010611806)，国家重点基础研究发展计划“973”项目(编号2007CB411301)，国家自然科学基金(编号40573038)资助成果。 |
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| 摘 要： | 塔里木北缘南天山蛇绿混杂岩带沿乌瓦门、库勒湖、依奇科里克、黑英山等地分布,黑英山段蛇绿混杂岩以梅什布拉克牧场一带出露最好。该蛇绿岩时代的确定事关天山造山带形成与演化历史的认识。对采自梅什布拉克蛇绿混杂岩带基质中的20多件硅质岩进行了薄片观察,从中挑选出若干件代表性硅质岩和硅质泥岩做微古化石鉴定,从中发现较多放射虫化石,属于内射虫类和原笼虫类,时代为晚泥盆世法门期—早石炭世杜内期—维宪期,早石炭世代表南天山洋盆关闭的年龄下限,或构造混杂的早期年龄。结合区域地质及其前人研究成果,认为南天山的乌瓦门、库勒湖、依奇科里克、黑英山各段蛇绿岩在物质组成与时空延伸上均有可比性,共同构成一个大型的南天山晚古生代构造缝合带。现有资料不支持南天山存在晚二叠世洋盆的认识。
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| 关 键 词： | 硅质岩 蛇绿混杂岩 放射虫化石 黑英山 南天山 |
| 修稿时间： | 2007-04-12 |
Age of Radiolarian Fossils from the Heiyingshan Ophiolitic Mélange, Southern Tianshan Belt, NW China, and Its Tectonic Significance |
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| SHU Liangshu,WANG Bo,ZHU Wenbin.Age of Radiolarian Fossils from the Heiyingshan Ophiolitic Mélange, Southern Tianshan Belt, NW China, and Its Tectonic Significance[J].Acta Geologica Sinica,2007,81(9):1161-1168. |
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| Authors: | SHU Liangshu WANG Bo ZHU Wenbin |
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| Institution: | Department of Earth Sciences,Nanjing University,Nanjing,210093 |
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| Abstract: | Heiyingshan is located in the Meisibulake pasture, 60 km northeast of Baicheng County, Xinjiang Uygur Autonomy Region, NW China. The Meisibulake ophiolitic m lange section is well exposed between the Silurian greenschist facies meta-deformation zone to the north and the overlying Carboniferous sandstone and limestone zone. The ophiolitic m lange zone is composed of mafic-ultra mafic rocks, limestone, chert blocks and flysch metrix. The mafic-ultra mafic rocks, limestone and chert are presented as the faulted blocks included within the sheared matrix that consists of muddy chert and siliceous mudstone. Radiolarian fossils are found in both chert block and siliceous matrix, including some entactinids and archocyrtids, which are identified to be Late Devonian to Early Carboniferous in age. This suggests that the age of the m lange should be a little later than that of the real ophiolite. It, therefore, could indicate that the lower limit of the closure age of the Southern Tianshan Ocean should be the Early Carboniferous, implying an initial age of the melange. Synthetic analyses with previous results indicate that the ophiolitic m lange segments distributed in Wuwamen, Kule Lake, Yiqikelik and Heiyingshan have similar petrotectonic assemblages and age, they constitute a large-scale Late-Paleozoic tectonic suture zone in Southern Tianshan collision. |
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| Keywords: | chert ophiolitic mé lange radiolarian fossils Heiyingshan Southern Tianshan |
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