摘要： 通过对塔里木盆地西南部(塔西南)江格结尔地区下白垩统克孜勒苏群地层剖面测量,该地区的克孜勒苏群分为5个岩性段,岩性主要为泥质粉砂岩、岩屑砂岩、含砾砂岩、砾岩等,沉积相主要为辫状河三角洲相;其上覆的上白垩统库克拜组为介壳灰岩、膏质泥岩,沉积相为浅海相、滨海潟湖相; 下伏的上侏罗统库孜贡苏组岩性主要为杂砾岩、含砂杂砾岩和石英砂岩等,沉积相为冲积扇相;三者呈整合接触。从该区下白垩统克孜勒苏群的沉积特征来看,早白垩世为陆源碎屑沉积环境,在晚白垩世转入海相沉积环境。对比该区北侧陆内造山带中的拉分断陷盆地(萨热克巴依盆地)中下白垩统克孜勒苏群的地层层序,该区仅沉积了下白垩统克孜勒苏群下部3个岩性段而缺失上部岩性段,表明在早白垩世后期塔里木盆地北侧西南天山发生过一次抬升作用。下白垩统克孜勒苏群是铜铅锌铀矿等金属矿产的赋矿层位,同时也是塔里木盆地石油和天然气的重要储集层位,在铜铅锌等矿石中常可见大量的沥青等有机质,这些有机质主要源于下伏侏罗系的煤系烃源岩,并通过成矿流体参与了金属矿产的成矿作用,因而这种多矿种“同盆共存”的现象,在沉积盆地的研究中作为整体的成矿系统来研究将更有意义。

关键词: 西南天山, 塔里木盆地, 下白垩统, 沉积特征, 矿产资源

Abstract: The Lower Cretaceous Kizilsu Group in Jianggejieer area,southwestern Tarim Basin,is divided into five lithologic units,which are mainly composed of argillaceous siltstone,lithic sandstone,pebbly sandstone,and conglomerate,and were mainly deposited in braided river delta settings. The Upper Cretaceous Kukbai Formation,overlying the Kezilesu Group,is composed of shell limestone and gypsum mudstone,and was deposited in shallow marine and littoral-lake settings. The Upper Jurassic Kuzigunsu Formation underlying the Kizilsu Group is mainly composed of conglomerate,sandy conglomerate and quartzose sandstone of alluvial fan facies. According to the sedimentary characteristic of the Lower Cretaceous Kizilsu Group in this area,terrigenous clastic deposition was dominated during the Early Cretaceous,whereas marine deposition during the Late Cretaceous. In contrast to the stratigraphic sequence of the pull-apart fault basin(the Sarekbayi Basin) in the north of intracontinental orogenic belt,the stratigraphic sequence of the Lower Cretaceous Kizilsu Formation in the Sarekbayi Basin only contain the lower three units,missing the upper lithologic units,and an uplift occurred in the southwest Tianshan Mountains in the north of the Tarim Basin during the late Early Cretaceous. The Lower Cretaceous Kizilsu Group is the ore-bearing layer of copper,lead,zinc and uranium deposits,and also an important reservoir for oil and natural gas in the Tarim Basin. Asphalt and other organic matter are often found in copper,lead,zinc and other ores. The organic matter was mainly originated from the coal-bearing source rocks of the underlying Jurassic strata,which was involved in the mineralization of metal minerals through ore-forming fluids. Therefore,the phenomenon of multi-mineral “coexisting in the same basin” will be more meaningful to study as a whole metallogenic system in sedimentary basin.

Key words: Southwest Tianshan, Tarim Basin, Lower Cretaceous, sedimentary characteristics, mineral resources

中图分类号: 

• P588.2