Geochemical Features of the Two Early Paleozoic Ophiolitic Zones and Volcanic Rocks in the Central-Southern Tianshan Region, Xinjiang  

作　　者：郭建  舒良树  夏飞雅克  卢汉斯巴坦  孙树文  

机构地区：[1]Department of Earth Sciences, Nanjing University, Nanjing 210093, China Institute of Geophysical Prospecting, Exploration and Production Research Institute, 21 Weigang,Nanjing 210014, China [2]Department of Earth Sciences, Nanjing University, Nanjing 210093, China [3]UMR 6530, CNRS FR009, Departement des Sciences de la Terre, Universit dOrleans, 45067 Orleans, France

出　　处：《Chinese Journal Of Geochemistry》2002年第4期308-321,共14页中国地球化学学报

基　　金：The research project supported by the National 973 Scientific Project of China (GrantNo.2 0 0 1CB4 0 980 4 ) ;the National NaturalScience Foundation of China (GrantNos.4 9832 0 4 0 ;4 9772 1 5 1 )and the Laboratoirede Geologie Structurale,Universit

摘　　要：This paper deals with the geochemical features of the two Early Paleozoic ophiolite zones in the central\|southern Tianshan region and the central Tianshan igneous rock belt between them. Study results suggest that the central Tianshan belt was an Ordovician volcanic arc with an affinity of continental crust, and the Kumux\|Hongliuhe ophiolitic zone that is located on the southern margin of central Tianshan has a crustal affinity to back\|arc marginal sea. The Aqqikkudug\|Weiya ophiolitic zone is an accretionary boundary between the Tuha continental block and the central Tianshan volcanic arc during Late Silurian to Devonian; Ordovician ophiolitic blocks, Silurian flysch sequence and HP metamorphic rock relics are distributed along the Aqqikkudug\|Weiya zone. Geochemically, ophiolitic rocks in the Aqqikkudug\|Weiya zone have an affinity to oceanic crust, reflecting a tectonic setting of paleo\|trench or subduction zone. The Early Carboniferous red molasses were deposited unconformably on the pre\|Carboniferous metamorphosed and ductile sheared volcanic and flysch rocks, providing an upper limit age of the central and southern Tianshan belts.This paper deals with the geochemical features of the two Early Paleozoic ophiolite zones in the central\|southern Tianshan region and the central Tianshan igneous rock belt between them. Study results suggest that the central Tianshan belt was an Ordovician volcanic arc with an affinity of continental crust, and the Kumux\|Hongliuhe ophiolitic zone that is located on the southern margin of central Tianshan has a crustal affinity to back\|arc marginal sea. The Aqqikkudug\|Weiya ophiolitic zone is an accretionary boundary between the Tuha continental block and the central Tianshan volcanic arc during Late Silurian to Devonian; Ordovician ophiolitic blocks, Silurian flysch sequence and HP metamorphic rock relics are distributed along the Aqqikkudug\|Weiya zone. Geochemically, ophiolitic rocks in the Aqqikkudug\|Weiya zone have an affinity to oceanic crust, reflecting a tectonic setting of paleo\|trench or subduction zone. The Early Carboniferous red molasses were deposited unconformably on the pre\|Carboniferous metamorphosed and ductile sheared volcanic and flysch rocks, providing an upper limit age of the central and southern Tianshan belts.

关 键 词：地球化学 古生代 火山岩 天山 新疆 

分 类 号：P588.1[天文地球—岩石学]