山西长治断裂的基本特征与第四纪活动性研究

实地调查表明,山西长治断裂由三段组成,南段和中段为西倾正断层,北段为东倾正断层,总体走向北东25o,长达65km,控制着附近山地与第四纪山间盆地的构造演化和地貌发育;第四纪早期,断裂发生强烈的垂直差异活动,最大垂直活动幅度可达400m左右;第四纪晚期,断裂活动性明显减弱,中段仍有活动,至少发生过两期活动,第—期活动发生于距今10.88万年左右或以后、1.49万年以前,第二期活动发生于距今1.49万年以后,垂直错距0.65m。

Geological Features and Activities of the Changzhi Fault, Shanxi, China

Based on field investigation, this paper describes geological features and tectonic activities of the Changzhi fault in southeastern Shanxi province, China. This fault strikes northeast to north, dips to west in the south and middle segments but to east in the north segment, and extends over a distance of 65km. Acting as both major geological and geomorphologic boundaries, this fault controls the regional neotectonic activity. In earlier Quaternary period, strong tectonic movement occurred along Changzhi fault with a vertical offset of 400m, which led to the formation of Changzhi and Licheng basins. During late Quaternary period, the activity intensity of both north and south segments decreases. However, along the middle segment scarps and offsets of young sedimentary deposits are observed in the field, which represents two possible faulting activities. The first one occurred between 108.8ka PB and 14.9ka PB, and the second one occurred after 14.9ka PB with a vertical offset of 0.65m.