桂林理工大学学报Issue(4)：575-586,12.DOI:10.3969/j.issn.1674-9057.2013.04.001
柴北缘滩间山群构造对南祁连加里东造山及超高压变质岩折返的启示
Structure Implication in Tanjianshan Group on Southern Qilian Caledonian Orogeny and Exhumation of UHP Metamorphic Rocks in Northern Qaidam
摘要
Abstract
The original Tanjianshan Group in Northern Qaidam can be decomposed into three parts by its stuc-ture and lithology.The lower rock formation is island-arc intermediate-basic volcanic rock series deformed and metamorphosed to greenschist facies mylonite .The middle rock formation is back-arc basin jet-sedimentary rock series in which deformational partitioning of greenschist facies occurred , belonging to the ore-bearing layer of Xitieshan-type Pb-Zn ore deposit.The upper rock formation is purple-red pebbled sandstone with slight de-formation and metamorphism .Structural analysis suggests that the lower rock formation of the original Tanjians-han Group belongs to Upper Cambrian-lower Ordovician,which is the product of ocean -continent collision sys-tem .The middle rock formation belongs to the middle-late Ordovician, the product of the Back-arc basin.The upper rock formation belongs to the early Silurian , the product of the foreland basin in the continent-continent collision system.The lower or middle rock formation and the gneiss of early Proterozoic Dakendaba Group are contacted with the base Detachment fault, while the upper rock formation or the thrust sheet of the Dakendaba Group and the middle rock formation are contacted with the upper detachment fault .The two detachment faults are characteristed by duplex thrust structure.Before the extensional collapse of the orogenic belt, the Dakenda-ba Group without eclogite was thrusted and stacked on the Tanjianshan Group , subsequently setback loss by the upper detachment fault during the Post-orogenic extensional, only partialy remaining relics.After the extension of orogenic belt, the Northern Qaidam was superimposed by intracontinental orogeny, the original Tanjianshan Group, thrust sheets.Nappe faults and detachment faults are transferred into the podiform inverted syncline to-gether, and superimposed on the late Devonian molasse basin .In Caledonian orogenic extensional period, the Altyn strike-slip fault was adjusted by early exhumation between north Qaidam and South Altyn UHP metamor-phic rocks, and the tectonic erosion of the UHP metamorphic belt at the follow-up of the extrusion and exten-sional system.关键词
滩间山群/南祁连造山带/超高压变质岩/折返机制/剥离断层/柴达木盆地北缘Key words
Tanjianshan Group/southern Qilian orogen/UHP metamorphic rock/exhumation mechanism/detachment fault/northern Qaidam分类
天文与地球科学引用本文复制引用
汪劲草,韦龙云,郝森,韦安伟,王永东..柴北缘滩间山群构造对南祁连加里东造山及超高压变质岩折返的启示[J].桂林理工大学学报,2013,(4):575-586,12.基金项目
国家自然科学基金项目（41172089）；广西自然科学基金项目（桂科自0832251；2012GXNSFAA053185）；广西矿冶与环境科学实验中心建设项目 （）
