塔里木盆地巴楚隆起海米罗斯断裂带几何学与运动学特征

Geometrical and kinematical characteristics of Haimiluosi fault zone in the Bachu uplift,Tarim Basin

作为塔里木盆地巴楚隆起边界断裂之一,海米罗斯断裂的构造样式及演化历史可反映巴楚隆起的形成原因及过程,可为探讨克拉通内构造变形机理提供依据。运用断层相关褶皱理论,对切过海米罗斯断裂带的数条二维地震剖面进行几何学分析,刻画了各断层在三维空间展布形态,结合断层断距及剖面缩短量探讨了断裂带活动性,并利用平衡剖面技术还原了断层剖面演化特征。研究认为,海米罗斯断裂带在平面上表现为帚状形态,剖面上表现为3层构造变形样式,其中新生界断裂和古生界断裂分别以古近系膏岩和中寒武统盐岩为滑脱面发生滑脱;断裂带位于南界断裂转走向折处,调节了两端断裂位移,断裂整体具有逆冲-走滑特征;海米罗斯断裂带为早期正断层基础上后期发生反转所形成的断裂带,中、晚奥陶世在加里东运动下正断层反转,逆冲断裂初始形成,并使已沉积地层发生低幅隆起。晚二叠世末期早期断裂复活并强烈长期活动,在始新世至渐新世主要形成新生界断裂,至第四纪时断裂带受喜马拉雅期运动影响再次运动并最终定型。

The tectonic style and evolution history of Haimiluosi fault zone,one of the boundary faults of Bachu uplift,can reflect the origin and process of the Bachu uplift formation,which will serve as a basis for exploring the intra-cratonic structural deformation mechanisms.Based on the fault-related fold theories,we analyzed the geometrical characteristics of several two-dimensional seismic profiles cutting through the Haimiluosi fault zone,and depicted the three-dimensional spatial distribution of the faults.Moreover,the tectonic activity of the fault zone was discussed according to the fault displacement and the amount of structural shortening on the profile.And the evolutionary features of faults on profiles were reconstructed using the balanced section technique.The results show that the Haimiluosi fault zone takes the shape of a broom on map,and is characterized by a three-layer structural deformation style on profile.Among them,the Cenozoic and Paleozoic faults take the Paleogene gyprock and Middle Cambrian saline rock as detachment surfaces respectively.The fault zone is located at the break along the strike of the southern boundary fault,accommodating the fault displacement at both ends of the southern fault,and features thrusting-strike-slipping on the whole.Besides,the zone formed through late inversion of the normal faults,that is,normal faults got inversed during the Middle and Late Ordovician due to the Caledonian movement,leading to the initiation of thrust fault and the mild uplifting of the deposited strata.At the end of Late Permian,the early faults reactivated and kept intensive activity for a long time.Subsequently,the Cenozoic boundary faults were formed mainly during the Eocene to Oligocene,and the fault zone reactivated and finalized gradually under the influence of Himalayan movement in the Quaternary.