塔里木盆地巴楚隆起卡拉沙依断裂带活动特征

Characteristics of Kalashayi Fault Zone Activities in Bachu Uplift,Tarim Basin

通过系统的地震资料综合解释,对塔里木盆地巴楚隆起卡拉沙依断裂上、下盘沉积地层厚度的变化及各界面与上、下部地层的接触关系、不整合面的发育特征及变化规律进行研究,以此来探讨卡拉沙依断裂各时期的活动特征。认为卡拉沙依断裂东、西两段呈现出截然不同的活动特征。主断裂东段,晚寒武世—奥陶纪,断裂无明显活动;早志留世晚期—早二叠世,断裂开始活动,呈现出逆冲推覆断裂的特征;经中二叠世的平静期,从晚二叠世开始又有一次逆冲推覆活动。而位于主断裂南侧的次级断裂,在晚寒武纪—中志留世,断裂无明显活动;从早中泥盆世开始,次级断裂开始活动,表现为压性断裂特征,逆冲推覆作用持续至早二叠世,经过中二叠世短暂的平静期,在晚二叠世还有一次继承性活动,但活动强度较弱。主断裂西段,奥陶纪时期,断裂开始活动并表现出张性断裂活动特征;经过志留纪—中二叠世的平静期,从晚二叠世开始,断裂西段发生正反转作用,逆冲推覆活动明显。次级断裂西段,在晚寒武世—早中二叠世并无活动,从晚二叠世开始,断裂开始活动,表现为强烈的逆冲推覆作用。

Based on the interpretation of seismic data, the residual thickness of sediment strata, contact rela-tionship between overlying and underlying strata, interfaces in the hanging wall and footwall blocks, and development characteristics and variational rules of unconformity in Kalashayi fault in Bachu uplift of Tarim Ba-sin were researched, moreover the characteristics of activities of Kalashayi fault in different stages were investi- gated. The results show that the east section and the west section of Kalashayi fault have different activities. In the east section, the fault is inactive from Late Cambrian to Ordovician, and thrusting nappe fault occurs from the late stage of Early Silurian to Early Permian; in Middle Permian the fault is inactive and thrusts again in Late Permian. The subsidiary faults located in the south of main fault are inactive from Late Cambrian to Early- Middle Silurian, then strongly thrust since Early Devonian and continue to thrust until Early Permian; after a quiet period within Middle Permian, the faults are weakly active in Late Permian. In the west section, the fault is inactive since Late Cambrian; in Ordovician, the fault is active to be an extensional fault; from Silurian to Middle Permian, there occurs a quiet stage; in Late Permian, the fault has undergone a positive inversion move-ment. The subsidiary faults in the west section are inactive from Late Cambrian to Middle Permian and are strongly active to be thrusting nappe faults since Late Permian.