塔里木盆地雅克拉断凸走滑作用及其形成机理

Strike-slip movement and its genetic mechanism in Yakela faulted salient, the Tarim Basin

罗小龙 汤良杰 谢大庆 邱海峻 蒋华山 杨勇 陈绪云 张宇航

Luo Xiaolong Tang Liangjie Xie Daqing Qiu Haijun Jiang Huashan Yang Yong Chen Xuyun Zhang Yuhang

雅克拉断凸是塔里木盆地含油气丰富且发现油气较早的地区之一。通过解释三维地震资料并结合区域地质资料,发现有多种证据表明该地区发生过走滑作用。平面上,研究区主干断裂附近区域发育众多小级别的断层,主要包括同向剪切断层和张性断层,它们表现为与主位移带呈一定角度的、延伸不长的雁列式断层系,断层系沿亚南断裂呈左阶式雁列排列,沿轮台断裂呈右阶式雁列排列;剖面上发现负花状构造样式,同时海豚效应与丝带效应明显。雅克拉断凸走滑作用始于燕山晚期运动,主要作用时期为喜马拉雅早期运动,止于喜马拉雅晚期运动。燕山中-晚期至喜马拉雅早期,因左旋扭应力与引张力合成的左旋张扭应力导致雅克拉断凸发生走滑作用并形成与之相关的伸展构造。

The Yakela faulted salient is a key area in the Tarim Basin where some economically important oil and gas have been discovered.The 3D seismic interpretations,in combination with the regional geological data,demonstrate that strike-slip movement occurred in the area.On plane view,many small faults are developed near the major faults,including concordant shear faults and extensional faults.These faults consist of echelon fault systems with a low-angle with the major movement direction and a limited length.The fault system along the Yanan fault is characterized by a left-step pattern,whereas a right-step pattern is shown along the Luntai fault.On sectional view,they consist of a negative flower-like structure with obvious dolphin and ribbon effects.The strike-slip movement initiated in the late Yanshanian,culminated in the early Himalayan,and terminated in the late Himalayan.The left-lateral transtensional stress from the joint action of the left-lateral shear stress and the tensile stress resulted in the strike-slip movement of the Yakelafult-salient and the deve-lopment of the associated extensional structures during the Middle-Late Yanshanian to the Early Himalayan.

10.11743/ogg20130218