库车坳陷库车河剖面重矿物分布特征及其地质意义

Characteristics of Mesozoic and Cenozoic heavy minerals from Kuche River section in Kuche depression and their geological implications

沉积物中的重矿物分布受物源、构造背景和古气候、古环境等多种因素影响 ,是盆山演化研究的良好指示剂。本文通过对库车坳陷库车河剖面中新生代地层的野外观察和重矿物分析 ,将库车坳陷中生代沉积与南天山隆升的分异作用分为 4个阶段 ,即早中三叠世、晚三叠世至早白垩世、第三纪古新世至中新世、上新世 (5Ma)以来 ,并认为最后一个阶段南天山隆升作用最强烈。将库车坳陷中新生代古气候演化分为 3个阶段 ,即早三叠世 (干旱半干旱 )、中晚三叠世—中晚侏罗世 (湿润半湿润 )、晚侏罗世以来 (半干旱干旱 )。

The distribution of heavy minerals in sediments is affected by such factors as provenance, geological setting, palaeoclimate and palaeoenvironment, which constitute sensitive indexes for the evolution of basins and mountains. The characteristics of sediments and heavy minerals in Kuche River section have been studied in this paper. According to the results obtained, the tectonic evolution of Kuche depression and South Tianshan in Mesozoic and Cenozoic can be divided into four periods, namely early and middle Triassic, late Triassic to early Cretaceous, Paleocene to Miocene, and Pliocene to the present, with the uplift of Tianshan in the last period being most intense. The palaeoclimate evolution of Kuche depression and South Tianshan in Mesozoic and Cenozoic can be divided into three periods, i.e., early Triassic (arid_semiarid), middle Triassic to middle Jurassic (humid_semihumid), and late Jurassic to the present (semiarid_arid).