|
|||||
|
|
| Geochemistry of ophiolite cherts from the Qinling orogenic belt and implications for their tectonic settings | |
| 作者姓名： | ZHANG Chengli GAO Shan ZHANG Guowei GUO Anlin YUAN Honglin LIU Xiaoming & WANG Jianqi . The key Laboratory of Continental Dynamics Ministry of Education |
| 作者单位： | ZHANG Chengli1，2，GAO Shan1，3，ZHANG Guowei1，GUO Anlin1，YUAN Honglin1，LIU Xiaoming1 & WANG Jianqi1 1. The key Laboratory of Continental Dynamics，Ministry of Education，Department of Geology，Northwest University，Xian 710069China; 2. State Key Laboratory for Mineral Deposits Research，Nanjing University，Nanjing 210093，China; 3. Department of Geochemistry，China University of Geosciences，Wuhan 430074，China |
| 基金项目： | 国家自然科学基金，the Foundations of Senior Visiting Scholarship of Colleges in Western areas and Backbone Teacher of Ministry of Education |
| 摘 要： | Since the 1980s, one of the important progresses in the study of the Qinling orogenic belt is marked by findings of numerous ophiolite zones1—4]. On the basis of the former orogenic models of the Paleozoic colli-sional orogeny1,5,6] and the Mesozoic collision7—9], another orogenic evolution model from the Paleozoic subduction-collision along the Shangdan suture to the Mesozoic final collision orogeny along the Mianle suture3,10], including the relicts of the Jining orogeny, has been pr… |
| 关 键 词： | Qinling orogenic belt radiolarian cherts ophiolite m閘ange zone. |
Geochemistry of ophiolite cherts from the Qinling orogenic belt and implications for their tectonic settings |
|
| ZHANG Chengli,,GAO Shan,,ZHANG Guowei,GUO Anlin,YUAN Honglin,LIU Xiaoming & WANG Jianqi . The key Laboratory of Continental Dynamics,Ministry of Education,.Geochemistry of ophiolite cherts from the Qinling orogenic belt and implications for their tectonic settings[J].Science in China(Earth Sciences),2004,47(4). | |
| Authors: | ZHANG Chengli GAO Shan ZHANG Guowei GUO anlin YUAN HongLin LIU Xiaoming Wang Jianqi |
| Institution: | 1. The key Laboratory of Continental Dynamics, Ministry of Education, Department of Geology, Northwest University, Xi'an 710069,China;State Key Laboratory for Mineral Deposits Research, Nanjing University, Nanjing 210093, China 2. The key Laboratory of Continental Dynamics, Ministry of Education, Department of Geology, Northwest University, Xi'an 710069,China;Department of Geochemistry, China University of Geosciences, Wuhan 430074, China 3. The key Laboratory of Continental Dynamics, Ministry of Education, Department of Geology, Northwest University, Xi'an 710069,China |
| Abstract: | Paleozoic cherts from the Mianlue and the Erlangping ophiolite zones of the Qinling orogenic belt are characterized by low Si/Al ratios (52.14-683.52 in the Mianlue cherts, 12.29-58.62 in the Erlangping cherts), Fe2O3 (0.01 -0.35 and 0.02-1.24) and high Al2O3/(Al2O3+Fe2O3)ratios (0.82-0.99 and 0.83-0.99). The negative correlation between Si2O and AI2O3 in the cherts reflects the important role of terrigenous components. The Erlangping cherts have Lar/Cen=0.9-1.15 and Ce/Ce*=0.95-1.15 with low contents of V, Ni and Cu, consistent with those of cherts forming on the continental margin. In contrast, the Ce/Ce* ratios of the Mianlue cherts range from 0.71 to 1.18 and Lan/Cen from 0.88 to 1.43 with slightly high V, Ni and Cu,which are similar to cherts found in the mid-ocean ridges and pelagic basins. Combined with the features of basic lavas associated with the cherts, it is suggested that during the Paleozoic, when the back-arc basin represented by the Erlangping ophiolite commenced shrinking in size in the mid-Ordovician, the southern Qinling was still in an extensional regime and finally grew into a new limited oceanic basin in the early Carboniferous. |
| Keywords: | Qinling orogenic belt radiolarian cherts ophiolite melange zone |
| 本文献已被 CNKI 万方数据 等数据库收录！ | |