祁连山北缘断裂带中段晚第四纪活动速率初步研究

发布时间：2018-06-12 22:52

本文选题：滑动速率 + Be　；参考：《地震地质》2017年01期

【摘要】：佛洞庙-红崖子断裂属于祁连山北缘断裂带中段逆冲推覆的前锋断裂,也是酒东盆地与祁连山之间的边界逆断裂。断裂运动学速率的准确限定对于理解青藏高原现今构造变形机制及其区域地震危险性至关重要。文中选取该断裂中、西段丰乐河口、石羊圈2个地点,通过地质地貌填图,综合应用地形剖面测量、光释光定年、宇宙成因核素定年和~(14)C定年等手段,获得了约40ka以来的断裂平均垂直滑动速率约为1.1mm/a;考虑到断裂倾角为40°~50°,平均缩短速率为0.9~1.3mm/a。跨酒东盆地的GPS速度剖面给出的酒东盆地10a尺度缩短速率约为1.4mm/a,与地质缩短速率1.0~1.5mm/a几乎一致;酒东盆地内部的隐伏断裂或褶皱变形也可能吸收部分地壳缩短。酒东盆地总体地壳缩短速率约占整个祁连山造山带缩短速率的1/5,高原向NE方向扩展的前锋带现今仍具有强烈的地震活动性。
[Abstract]:The Fotongmiao-Hongyazi fault belongs to the front fault of thrust nappe in the middle segment of the northern margin of Qilian Mountains and is also a boundary thrust fault between the Jiudong Basin and Qilian Mountains. The accurate limit of fault kinematics rate is very important to understand the present tectonic deformation mechanism of Qinghai-Xizang Plateau and its regional seismic risk. In this paper, two sites of the fault, Fengle Estuary and Shiyangzhuang, are selected. By means of geological and geomorphologic mapping, topographic profile survey, photoluminescence dating, cosmic radionuclide dating and Yi-14C dating, etc., are used in this paper. The average vertical slip rate of the fracture is about 1.1 mm / a since 40ka, and the average shortening rate is 0.9 ~ 1.3 mm / a considering the fault dip angle of 40 掳/ 50 掳. The velocity profile of the Jiudong basin gives a 10a shortening rate of about 1.4mm / a, which is almost consistent with the geological shortening rate 1.0~1.5mm/a, and the concealed faults or fold deformation in the Jiandong basin may also absorb some crustal shortening. The total crustal shortening rate in Jiudong basin accounts for about 1 / 5 of the shortening rate of the Qilian orogenic belt. The front belt of the plateau extending towards NE still has strong seismicity.
【作者单位】：中国地震局地质研究所活动构造与火山重点实验室;
【基金】：中国地震活动断层探察-南北地震带北段项目(20140823)资助
【分类号】：P315.2

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