新疆库车盆地古近系—新近系蒸发岩沉积旋回识别及对比  

Identification and correlation of the Paleogene and Neogene evaporites sedimentary cycles in Kuqa Basin, Xinjiang

作　　者：曹养同[1] 刘成林[1] 杨海军[2] 顾乔元[2] 焦鹏程[1] 卢玉红[2] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]中国石油塔里木油田分公司,新疆库尔勒841000

出　　处：《古地理学报》2010年第1期31-41,共11页Journal of Palaeogeography：Chinese Edition

基　　金：塔里木盆地重要蒸发岩坳陷成盐及油气生储条件研究项目(编号:41005050002);国家"十一五"科技支撑课题(编号:2006BAB07B06);中国地质科学院矿产资源研究所中央级公益性科研院所基本科研业务项目(编号:K0807)共同资助

摘　　要：库车盆地古近纪—新近纪发育巨厚的蒸发岩沉积,根据蒸发岩沉积旋回的变化,即由于盐湖水体由淡—咸—盐—咸—淡的旋回变化,相应地沉积物发生由碎屑岩—膏岩—盐岩—膏岩—碎屑岩的变化。考虑钻井的分布位置及其剖面在时代上的完整性,选取盆地中13口井的钻井剖面进行沉积旋回识别和对比,共识别出5个蒸发岩沉积旋回,其中库姆格列木群两个,苏维依组一个,吉迪克组两个。通过对比,确立了以东秋8井剖面为库车盆地蒸发岩沉积旋回对比的标准剖面。初步分析认为,盆地蒸发岩沉积旋回的沉积区迁移特征,应受盆地基底控制和南北向构造挤压应力变化的影响。古近系蒸发岩主要分布在盆地西部,新近系吉迪克组沉积时期,盆地西北部转为陆源碎屑岩沉积(西南部发育少量蒸发岩),而东部发育巨厚的蒸发岩,显示出东西分带的特点。在始新世末印度板块和欧亚板块碰撞的远距离效应影响下,库车盆地自苏维依组沉积时期蒸发岩沉积中心就已经开始迁移,迁移中心一分为二,自盆地北西分别向南、向东移动,形成两个沉积区,吉迪克组沉积时期在上述两个沉积区继续发育盐岩、膏岩沉积。Very thick evaporites were developed in the Kuqa Basin from the Paleogene to Neogene period. Based on variation of sedimentary cycles, which means that when the water of saline lake changes from fresh water, saline water, to brine, and then to saline water, fresh water, accordingly, the sediments change from clastics, gypsum, to halite, and then to gypsum, clastics correspondingly. Considering the distribution of drilling holes and the integrity of sections selected, 13 drilling holes were chosen to be identified and correlated on sedimentary cycles of evaporites, and five sedimentary cycles were founded, 2 belonging to the Kumugeliemu Group, 1 belonging to the Suweiyi Formation, and the others belonging to the Jidike Formation. By comparing and contrasting, the stratigraphic section of Dongqiu 8 drilling hole was constructed as a standard section, and the shifting characteristics of sedimentary areas of 5 cycles were given approximately in the Kuqa Basin. With the action of north-south compressional force and influence of the basement in the Kuqa Basin, the evaporites were developed in the western Kuqa Basin during the Paleogene, and during the deposition of the Jidike Formation, the sediments turned into clastic rocks（a small amount of evaporites in the southwestern area）, but in the eastern Kuqa Basin,very thick evaporite sediments were developed during the Neogene. A distinct belt came into being between the eastern and western areas of the basin. Because of the influence of two kinds of remote structural effects resulting from the India and Qinghai-Tibet Collision,depositional centres of evaporites began to move from the depositional period of the Suweiyi Formation and the centre shifted from northwest to south and east, and thus 2 sedimentary areas came into being, accordingly,very thick halite and gypsum were developed in the 2 areas continuously during the depositional period of the Jidike Formation.

关 键 词：蒸发岩 沉积旋回 识别及对比 库车盆地 

分 类 号：P588.247[天文地球—岩石学]