摘要
本区存在大型中生代推覆构造,所有震旦纪—古生代的沉积岩层都卷入了褶皱和断裂,构造推覆发生在较高构造部位,属脆性变形域,以台阶状逆断层和断层相关褶皱为特征。区内存在若干推覆构造,每个岩片均可分为上盘、下盘和滑动层系三部分,共查明8个滑动岩系。是一种发生在早中生代的盖层推覆,无根褶皱,也是徐宿地区最重要的控煤构造。最后对推覆构造的地球动力学机制进行了讨论。
Large scale thrust tectonics occurred in Early Mesozoic in the Xuzhou- Suzhou region,southern margin of North China plate.The strata that were involved in this thrust tectonics are Neo- Proterozoic- Paleozoic sedimentary layers,characterized by strongly brittle deformation of step- type thrusting and fault- related folding (fault propagation fold).Thrust flakes with various scales and shapes were developed well in the Jiagou- Taoshanji area;each flake consists of upper rock- block,slipping fault and lower rock- block.Eight slipping beds that are related to thrust tectonics were reported.The paper researched geometry,kinematics,timing of emplacement and shortening rate of thrust bodies.Thrust structural styles include superimposition- type and step- type; duplex- type and klippe- type also develop in the region.The Xuzhou- Suzhou arc tectonics can be divided into three parts from east to west:(1) the Tan- Lu thrust root zone,marked by lower- angle thrust of Neo- Proterozoic with weakly ductile shear deformation,(2) the Jiagou- Taoshanji middle zone,characterized by fault- related fold,step- type thrust with lower- middle dip angle of fault,(3) the northern Anhui- Xiaoxian County front zone of superimposion thrust with high- angle of fault.Regional detachment fault is located between the Neo- Proterozoic rocks and Paleo- Proterozoic metamorphic basement in the deep crust;thrust structures that occur at surface are a cover thrust of the Paleozoic sedimentary rocks.Authors described in detail the three typical structural phenoma,that is,the Lihuashan- Zhangzhuang superimposition thrust zone,the Wuyanquan step- type thrust zone and the Dashankou- Changwo klippe zone.The movement of thrust is from ESE to WNW,namely from Tan- Lu fault zone to North Anhui.Large- scale thrust tectonics in the studied area constrained the distribution and richness of coal beds.Study results suggest that the large- scale thrust event was caused by Early Mesozoic intracontinental subduction and took place after Late Triassic and prior to Late Jurassic,corresponding with a collision between the North China continent and Yangzi continent along the Dabieshan suture zone.
出处
《大地构造与成矿学》
EI
CAS
CSCD
2000年第3期208-217,共10页
Geotectonica et Metallogenia
基金
国家自然科学基金重点资助项目!(批准号:49632080)
关键词
中生代
夹沟--桃山集
推覆构造
动力学机制
分析
Step- type thrust fault
fault- related fold
Mesozoic
Jiagou- Taoshanji area