酒店垭-桑木场构造须家河组节理发育特征与应力场解析

川东南构造应力应变以及构造期次的划分，是近年来四川盆地演化分析的重点研究对象。明确其构造演化与古应力场关系对于后期深化研究四川盆地边缘应力演化、指导本地区油气勘探具有重要意义。通过对酒店垭-桑木场背斜两翼须家河组露头观测到452组节理进行处理、统计、分析，利用传统的构造几何学分析方法、磷灰石裂变径迹以及声发射实验并结合相关区域构造演化史资料，分析了研究区裂缝发育期次以及古构造应力场。结果表明：该区主要为两套构造节理，分别为近NW—SE向和近NE—SW向两期主构造应力作用形成的节理；研究区自三叠纪之后发生了至少两期以上对该地区具有重大影响的构造运动：第一期为燕山运动中—晚期，最大主应力轴方向为133°，主要形成NE、NNE向断裂体系，构造规模较大、断裂发育；第二期为燕山运动末期-喜马拉雅运动早期，最大主应力轴方向为51°，主要形成NW向构造体系，构造规模较小、断裂仍较发育。

Characteristics and Tectonic Stress Field of Joints in Xujiahe Formation of Jiudianya-sangmuchang Structure

The study of paleotectonic stress field and division of tectonic stages in the Southeastern Sichuan, is one of the key research object for the analysis of the evolution of the Sichuan basin in recent years. It is of great significance to clarifying the relationship between tectonic evolution and paleo stress field, and to further studying the stress evolution of the margin of Sichuan basin and guiding oil and gas exploration in the later period. Based on the analysis of the 452 group joints observed in the Xujiahe Formation of the Jiudianya sangmuchang structure, using the structural geometrical analysis method and the apatite fission track and the acoustic emission experiment combined with the relevant regional tectonic evolution history, the phases and the tectonic stress field in the study area were analyzed. The results show that there are two sets of structure joints in this area, which are the joints formed by the two main tectonic stresses of nearly NW-SE direction and near NE-SW direction. This region has at least two or more tectonic movements which have a great influence on the area since the Triassic: the first phase is the middle and late period of the Yanshan Movement. The direction of the maximum principal axes of stresses is 133°, mainly forming tectonic system with a large scale in NE and NNE directions. The fracture is relatively developed. The second stage is the late stage of the Yanshan Movement early Himalayan Movement. The direction of the principal axes of stresses is 51°, mainly forming structural system in NW direction with a small scale, but the fracture is still relatively developed.