摘要
准噶尔盆地玛湖凹陷下三叠统百口泉组为一套扇三角洲沉积体系,以粗碎屑沉积为主,夹少量的泥岩。为了恢复百口泉组沉积时期水体的古盐度,并与上二叠统乌尔禾组、中三叠统克拉玛依组的古盐度对比,对上述3个组岩心中的泥岩样品开展了全岩黏土矿物分析和微量元素测试,采用硼元素法、锶钡比、硼镓比等方法恢复百口泉组沉积时期水体的古盐度。结果表明,泥岩样品中黏土矿物以伊蒙混层为主,适合用科奇公式恢复古盐度。玛湖凹陷乌尔禾组、百口泉组一段、百口泉组二段、百口泉组三段和克拉玛依组的平均古盐度分别为7.0‰,5.0‰,7.2‰,8.9‰和8.4‰,反映当时水体为淡水—微咸水环境;黄羊泉扇与夏子街扇百口泉组表现出不同的古盐度变化趋势,黄羊泉扇的古盐度值较低,而夏子街扇的古盐度值相对较高,可能与所选井位的古沉积环境有关。此外,锶钡比和硼镓比也指示玛湖凹陷晚二叠世—中三叠世水体为淡水—微咸水环境。
The Lower Triassic Baikouquan formation in the Mahu sag,Junggar basin is a set of sedimentary system of fan delta,which is dominated by coarse detrital deposits with a small amount of mudstones.In order to restore the paleosalinities of the water body during the deposition of the Baikouquan formation,and compared with those of the Upper Permian Wuerhe formation and Middle Triassic Kelamayi formation,whole rock tests of clay minerals and trace elements are carried out for the mudstone samples in the cores obtained from the above three formations.The methods such as Boron element,Sr/Ba ratio and B/Ga ratio are used to restore the water paleosalinities during the deposition of the Baikouquan formation.The results show that the clay minerals in the sample are dominated by illite/montmorillonite mixing layer,so Coach formula is suitable to be adopted to restore the paleosalinities.The average paleosalinities of the Upper Permian Wuerhe formation,T1b1,T1b2,T1b3and Middle Triassic Kelamayi formation are7.0‰,5.0‰,7.2‰,8.9‰and8.4‰,respectively,indicating that the water at that time was fresh water-brackish water environment.The Baikouquan formation in Huangyangquan fan and Xiazijie fan exhibits different paleosalinity variation trend,relatively low paleosalinity of Huangyangquan fan and relatively high paleosalinity of Xiazijie fan may be related to the palaeosedimentary environment of the selected well locations.In addition,both Sr/Ba ratio and B/Ga ratio indicate a fresh water-brackish water environment in Mahu sag during Late Permian to Middle Triassic.
作者
黄云飞
张昌民
朱锐
易雪斐
瞿建华
唐勇
HUANG Yunfei;ZHANG Changmin;ZHU Rui;YI Xuefei;QU Jianhua;TANG Yong(Yangtze University School of Geosciences Wuhan, Hubei 430100, China;Research Institute of Exploration and Development, Xinjiang Oilfield Company, PetroChina,Karamay, Xinjiang 834000, China;Yangtze University Hubei Collaborative Innovation Center of Unconventional Oil and Gas,Wuhan, Hubei 430100, China)
出处
《新疆石油地质》
CAS
CSCD
北大核心
2017年第3期269-275,共7页
Xinjiang Petroleum Geology
基金
国家自然科学基金(41502012)
长江青年基金(2015cqn27)
关键词
准噶尔盆地
玛湖凹陷
百口泉组
黏土矿物
微量元素
古盐度
沉积环境
Junggar basin
Mahu Sag
Baikouquan formation
clay mineral
trace element
paleosalinity
sedimentary environment
