柴达木盆地南缘断裂晚第四纪活动性

The Study of Late Quaternary Activity of the Southern Margin of Qaidam Basin Fault

柴达木盆地南缘断裂是柴达木盆地与东昆仑构造带的分界断裂,断裂带西起甘森镇乌拉尔,终止于诺木洪以东,全长约500 km。以往对南缘断裂研究程度较低,且活动性存在争议。前人普遍认为柴达木盆地南缘断裂为隐伏断裂,本研究首次发现该断裂在小灶火段发育出露地表的断层陡坎。通过在小灶火段断层陡坎上挖掘探槽,在格尔木以南的隐伏段采用浅层人工地震结合钻孔联合剖面探测的方法,使用OSL测年方法对地层年龄进行分析测试,探究了断裂活动性。结果表明柴达木盆地南缘断裂小灶火段为晚更新世活动断层,格尔木隐伏段不活动。

The faults along the southern fringe of the Qaidam basin serve as the boundary between the Qaidam basin and the eastern Kunlun Mountains.These faults extend approximately 500 km,beginning at Ural in Gansen town in the west and terminating at Nuomuhong in the east.Research on these southern margin faults has been limited,leading to controversy regarding their activity.Historically,it has been assumed that the southern margin fault of the Qaidam basin is a blind fault.This study identifies surface rupture at the Xiaozaohuo segment of the southern margin fault,characterized by fault scarplets.To gain further insight into the fault's activity,we employed the OSL dating to analyze and determine the stratigraphic age.A trench was excavated at the Xiaozaohuo segment,and a shallow seismic investigation was conducted at the Golmud segment.The findings indicate that the Xiaozaohuo section is an active fault dating back to the late Pleistocene,while the Golmud hidden section has shown no signs of fault movement since that period.This research contributes to a better understanding of the seismic activity of the southern margin faults of the Qaidam basin.