塔里木盆地西部的新生代断裂活动

研究区以塔里木盆地西部的巴楚隆起为核心,包括其南侧的麦盖提斜坡和北侧的北部坳陷(阿瓦提凹陷)。这里新生代断裂异常发育。以鸟山-古董山地区为重点,通过精细的地震剖面解释,在塔里木盆地西部识别出5期新生代断裂活动,分别发生于:白垩纪末-古近纪初(ca.65Ma)、中新世末-上新世初(ca.5Ma)、上新世末-更新世中期(ca.3~1.5Ma)、更新世中-晚期(ca.1~0.1Ma)和全新世(ca.0.01Ma)。中寒武统和古近系膏盐层构成了研究区的2个主滑脱面。ca.65Ma的冲断受控于基墨里中间大陆与亚洲大陆碰撞的远程效应;ca.5Ma、ca.3~1.5Ma、ca.1~0.1Ma和ca.0.01Ma的断裂活动(包括滑脱断层、冲断层、走滑断层和正断层)均受控于印度-亚洲碰撞的远程效应。晚新生代(中新世以来)的断裂活动以脉动式冲断为特征,两次相邻脉动式冲断之间为时间不等的短暂的构造间歇期;间歇期构造平静,甚至可以形成正断层。

The Cenozoic faults in western Tarim Basin, NW China.

The study area includes Bachu Rise and Markit Slope on its south, North Depression(Awati Sag) on its north. Cenozoic faulting is abnormal active here. Take Niaoshan-Gudongshan area as the representative study area, five phases of Cenozoic faulting was found after careful seismic interpretation in the western Tarim Basin. They are:end Cretaceous-beginning Paleogene(ca. 65Ma), end Miocene-beginning Pliocene(ca. 5Ma), end Pliocene-middle Pleistocene(ca. 3~1.5Ma), middle-late Pleistocene(ca. 1~0.1Ma) and Holecene(ca. 0.01Ma). Gypsum-salt layer in Middle Cambrian and Paleogene serve as the two main detachment layers in western Tarim. Thrusting of ca. 65Ma was induced by the far-field effect of the Lhasa-Asia collision; Faulting(detachment fault, thrust fault, strike slip fault and normal fault) of ca. 5Ma, ca. 3~1.5Ma, ca. 1~0.1Ma and ca. 0.01Ma were induced by the far-field effect of the India-Asia collision. Late Cenozoic(after Miocene) faulting is characterized by numerous pulses of thrust. Between each two neighboring thrust pulses is a short tectonic pause, when the tectonic is calm, thrusting is ceased and even occur normal faulting.