新疆南天山北轮台断裂东段晚第四纪活动特征的初步研究

发布时间：2018-06-23 19:26

本文选题：天山 + 北轮台断裂　；参考：《新疆大学》2015年硕士论文

【摘要】：天山是欧亚大陆内部最大的一条造山带(Avouce et al.,1993;Hendrix et al.,1994;邓起东等)。现如今对于天山的统一认识为:第四纪以来,天山的构造活动主要以山前、山间盆地边缘的逆冲推覆为主,如北天山山前的推覆构造体(Avouce et al.,1993;邓起东等,2000)、南天山山前的库车坳陷(冯先岳等,1991)和柯坪推覆构造(Yin et al.,1998)等。本文主要研究了位于新疆天山南麓山前库车坳陷东侧的北轮台断裂。该断裂全长超过300km,晚第四纪以来活动强烈,控制着塔里木盆地北缘中、新生代地层分布,沿断裂多处可见到古生界地层逆冲至中、新生界地层之上,局部有切割全新统现象,是一个长期继承性活动断裂带。沿断裂多处分布有清晰的古地震形变带,显示出该断裂具有强烈的活动性。由于该断裂距离库尔勒市仅10公里左右,对库尔勒市的发展规划产生了影响,且该活动断层可能对周围城市库尔楚市造成地震灾害。为此本论文通过遥感解译法、地貌学方法、探槽方法和年代学方法等对该断裂几何特征、地质地貌特征和典型段古地震特征进行了初步的研究。通过研究我们得到了以下结论:1.北轮台断裂位于新疆南天山与塔里木盆地之间,逆冲推覆是其最主要的构造变形方式之一。该断裂整体呈现NWW—EW向展布,全长约300km,断层面倾向N,倾角50~80°沿断裂不仅形成了典型的断错地貌特征,而且还存在多期古地震事件。2.北轮台断裂从西向东分为5个较大的自然不连续段落:拉依布拉克至野云沟段(130km)、野云沟至阿克艾肯沟段(50km)、库尔楚至吉格代布拉克段(40km)、吉格代布拉克至库尔勒段(20km)以及库尔楚至铁门关水库段(100km)。3.通过微地貌测量、断层陡坎地形测量,以及探槽剖面研究分析我们发现在喀腊萨喀拉阿塔木沟探槽附近至少发生过三次大型古地震事件,其时间均位于晚第四纪。4.在库尔勒西帝禾农业探槽附近,我们通过地质地貌特征的研究和探槽剖面的分析发现该区域至少发生过两次大型古地震事件。
[Abstract]:Tianshan is the largest orogenic belt in Eurasia, (Avouce et al.1993, Hendrix et al. 1994; Deng Qidong et al. Nowadays, the unified understanding of Tianshan is that since the Quaternary, the tectonic activities of Tianshan are mainly in the front of mountains and the thrust and nappe in the margin of intermountain basins. For example, the nappe tectonics in front of North Tianshan Mountain, (Avouce et al. 1993; Deng Qidong et al., 2000), Kuqa Depression in front of South Tianshan Mountain (Feng Xianyue et al. 1991) and Keping nappe structure (Yin et al., 1998), etc. In this paper, the north Luntai fault located at the east side of Kuqa depression at the south foot of Tianshan Mountain, Xinjiang is studied. The fault is over 300km in length and has been active since the late Quaternary, controlling the distribution of Mesozoic and Cenozoic strata in the northern margin of the Tarim Basin. Along the fault, the Paleozoic strata can be seen thrust to the Mesozoic and the Cenozoic strata, and there is a phenomenon of cutting new series locally. It is a long-term inherited active fault zone. There are clear paleoseismic deformation zones along the fault, which shows that the fault has strong activity. Because the fault is only about 10 kilometers from Kurla City, it has an impact on the development planning of Kurla City, and the active fault may cause earthquake disaster to the surrounding city of Kurchu City. In this paper, the geometrical characteristics, geological features and paleoseismic characteristics of the fault are preliminarily studied by means of remote sensing interpretation, geomorphology, grooving and chronology. By studying, we get the following conclusion: 1. The north Luntai fault lies between the southern Tianshan mountain and the Tarim basin in Xinjiang, and the thrust and nappe is one of the main structural deformation modes. The whole fault is NWW-EW, with a total length of about 300 km. The fault plane inclines to N, and the dip angle of 5080 掳along the fault not only forms the typical fault-fault geomorphologic characteristics, but also has many paleoearthquake events. 2. The north Luntai fault is divided into five large natural discontinuities from west to east: from Raeblak to Yeyungou (130km), from Yeyungou to Akaiken gully (50km), from Kuerchu to Jigdebrak (40km), and from Jigdebrak to 20km. And Kulchou to Tienmen Guan Reservoir Section (100km). 3. By means of microgeomorphology survey, fault steep ridge topographic survey, and trough profile study, we found that at least three large paleoearthquakes occurred near the Kalasakaraamu grooves, all of which took place in the late Quaternary. Based on the study of geological and geomorphologic characteristics and the analysis of trench profiles, it is found that there were at least two large paleoearthquakes in the area near the Kulla Xidihe agricultural exploration trough.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P548;P315.2

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