塔里木盆地巴楚隆起断裂系统主要形成时代的新认识

巴楚隆起是塔里木盆地的一个次级构造单元,内部断裂走向以北北西向为主,北侧与之相邻的柯坪冲断带走向近东西向,属于南天山构造体系。两个断裂系统在平面上呈近于正交的关系。巴楚隆起大面积缺失中-新生界,其内部断裂体系起始活动时间的确定较为困难。本文通过对于巴楚和柯坪地区新生代地层序列特征对比研究及其接触关系分析,指出中新世巴楚隆起南北向断裂体系开始形成,向北一直延伸到柯坪构造带之中。同时对两个构造单元的南北向断裂的对应性进行了研究,指出柯坪东西向断裂系统的主要活动期是上新世(N₂)以后,现今柯坪构造带南北向和东西向断裂体系是不同时期构造的叠加。以此给出了巴楚和柯坪断裂体系形成的构造地质模型。

MAIN PERIOD FOR CREATION OF FRACTURE SYSTEM IN THE BACHU UPLIFT, TARIM BASIN

The Bachu uplift was a structural sub-unit in the Tarim Basin, where the fracture system was NNW-striking. The Kalpin fold-and-thrust belt was situated in the northern part of the Bachu uplift, which attached to the southern Tianshan structural systems. The fracture lines of the both met rectangularly. It was very difficult to confirm the faults formation period, because of stratigraphic absence of the Mesozoic and Palaeozoic in the Bachu uplift. After studying the Cenozoic stratigraphic characteristics and contact relation, the authors pointed out that the N-S strike fracture system of the Bachu uplift came into play in Miocene (N₁), and extended into the Kalpin structural belts northwards. The corresponding relation of N-S striking fracture system was discussed in two structural units. The Kalpin E-W striking fracture system developed since Pliocene (N₂). The Kalpin orthogonal fracture systems were superimposed deformation within difference structural movements. Based on mentioned-above, a structural model for the Bachu-Kalpin area was put forward.