摘要
东天山康古尔塔格构造带是准噶尔地块和塔里木板块的晚古生代弧-弧碰撞缝合带,厘定、分析构造带的组成、结构与晚古生代构造演化,有助于深化东天山古生代构造与资源效应的理解与认识。带内主要出露晚古生代造山中形成及卷入的建造、构造-岩石组合,总体呈现不同构造岩片相互叠置而成的一走向近东西的大型逆冲推覆构造带,其中部最宽处由南北两个组成和结构不同的褶皱-冲断带组成,空间上构成一具对称结构特征的对冲型组合样式;主要经历了低角度的分层剪切或逆冲剪切(S1//S0)→南北向横向缩短→近东西向走滑剪切3个阶段的晚古生代构造演化;低角度剪切(S1//S0)向横向缩短的转换时间为(276.5±2.9)Ma,表明随着海盆关闭、开始由双向俯冲进入碰撞造山阶段,而近东西向走滑剪切沿北部的康古尔断裂带最发育,属时限为262.9~242.8 Ma的新生叠加构造,代表已由碰撞造山转入陆内调整构造体制。现今东天山中段的造山带碰撞前锋主体仍隐伏于晚古生代晚期的海相沉积之中或之下。
The Kangurtag zone in the eastern Tianshan is a arc-arc collection suture zone resulted from the final a Malga Mation of the the Tarim plate to the Junggar block.To study on the Composition,structure and the late Paleozoic evolution of kanggurtag belt can help to gain a further knowledge of the Paleozoic tectonic evolution and its resource effect of Eastern Tianshan.This structural zone is dominated by the reworked pre-existing structural units and syntectonic petrotectonic assemblage during orogeny.And it’s general geological framework consists of a large-scale nearly EW trending structural stack of thrust slices.Our new data from the widest place in the middle of which support the Kangurtag zone is a re Markable two-sided symmetrical belt composed of two fold-thrust belts characterized by differently structural units and opposing vergence directions respectively.The northern one verges southward,whereas the southern one verges northward.The investigation of the structural evolution of the study area revealed three defor Mational events(D1—D3)from low-angle layer-parallel shearing or thrust shearing(D1)to SN directed horizontal shortening(D2)and subsequently following by nearly EW trending shearing(D3).The time of transition from low-angle layer-parallel shearing to horizontal shortening at(276.5±2.9)Ma represents the initial collision of the facing subduction complexes.Nearly E-W strike slip shearing is superposes on early structures during 262.9~242.8 Ma and actives intensively along the Kangur fault in the north of the region.This suggests the transition of the regional tectonic environment from collision between plate or blocks to intraplate defor Mation mechanism.And the Main part of the front collision belt is still concealed in or under the late Paleozoic Marine sediments in the middle of Eastern Tianshan orogeny.
作者
张忠义
肖文进
郑小明
杨国龙
高军辉
ZHANG Zhongyi;XIAO Wenjin;ZHENG Xiaoming;YANG Guolong;GAO Junhui(China Non-ferrous Metals Resource Geological Survey,Beijing 100012,China)
出处
《矿产勘查》
2021年第7期1530-1538,共9页
Mineral Exploration
基金
新疆维吾尔自治区地勘基金项目(T14-1-LQ12)
中国地质调查局地质调查二级项目(DD20160011)资助
关键词
东天山
康古尔塔格带
组成
结构
晚古生代
构造演化
eastern Tianshan
Kanggurtag belt
composition
structure
the late Paleozoic
tectonic evolution
