云南大具断裂晚第四纪分段特征初步研究

Preliminary Study on the Quaternary Segmentation Characteristics of the Daju Fault in Yunnan

摘要: 大具断裂位于云南丽江北部，是川滇菱形块体西边界附近的一条北西向断裂，晚第四纪以来活动具有分段性。本文在Google Earth影像解译基础上，结合断裂几何结构、地质地貌特征和活动时代，对大具断裂的活动性分段进行了初步研究。研究结果表明：大具断裂以马家村为界可以分为北西和南东两段，北西段为中甸–马家村段，线性地貌特征不明显，局部地段发育线性槽谷，最新活动时代为晚更新世；南东段为马家村–大东段，该段地貌上线性构造清晰，发育断层沟槽、断层崖、断层陡坎等断层地貌，活动时代为全新世。通过解译及实地考察，认为大具断裂是以右旋走滑为主兼具倾滑特征的活动断层。

Abstract: The Daju fault is located in the northern part of Lijiang, Yunnan Province. It is a northwestward fault near the western boundary of the Sichuan-Yunnan diamond block. It has segmental activity since the late Quaternary. Based on the interpretation of Google Earth image, combined with the fracture geometry, geological features and activity era, this paper conducts a preliminary study on the active segmentation of large faults. The results show that the Daju fault can be divided into northwest and southeast by Majiacun, and Zhongdian-Majiacun section in the northwest. The linear geomorphological features are not obvious, and the linear troughs are developed in the local area. The latest activity period is late. The Pleistocene, the southeastern section, is the Majiacun-Dadong section. The linear structure of the section is clear, and faults, fault cliffs, faults and steep ridges are developed. The active period is Holocene. Through interpretation and field investigation, it is believed that the large fault is an active fault with both right-lateral strike-slip and tilting characteristics.