摘要
前寒武系是全球重要的含油气层系,塔里木盆地前寒武系埋深大,是否发育规模性的优质烃源岩层段一直没有定论。近期,在塔里木盆地东南缘阿尔金地区进行野外考察时,于新疆若羌县红柳沟新发现一套厚层黑色泥页岩。野外露头剖面实测显示,剖面发育连续,厚约为326.2 m,底部为千枚岩段;下部为硅质岩段,厚约为180.1 m,以硅质岩、砂质泥岩和粉砂岩为主;上部为砂泥岩段,厚约为132.3 m,以黑色泥页岩、砂质泥岩和粉砂岩为主;实测剖面上覆叠层石白云岩。新发现的黑色泥页岩位于剖面上部砂泥岩段的中亚段,厚约为60 m,有机碳含量(TOC)为1.04%~4.81%,发育在还原沉积环境。剖面下部粉砂岩碎屑锆石U-Pb年龄显示,这套黑色泥页岩的最大沉积年龄晚于新元古代拉伸纪晚期,其形成可能与全球性的冰期事件相关。虽然新发现的黑色泥页岩未获得精确的年代学数据,但区域地质概况、野外地层接触关系、新获得的碎屑锆石U-Pb年龄等证据都支持这套黑色泥页岩沉积时代在寒武纪之前,它可能为塔里木盆地周缘目前发现的一套品质较好的古老烃源岩,具有重大的油气勘探价值及古环境研究意义,并坚定了在塔里木盆地深层古老地层开展油气勘探的信心。
The Precambrian is an important petroliferous system in the world.The Precambrian in the Tarim Basin has a large depth of burial,and it is uncertain whether large-scale high-quality hydrocarbon source rocks are developed.Recently,the team discovered a new set of thick black shale in Hongliugou,Ruoqiang County,Xinjiang Uygur Autonomous Region during field investigation in the Altun area,southeastern margin of the Tarim Basin.Field measurements of outcrop profile show that the profile is developed continuously with a thickness of ca.326.2 m and a phyllite section is at the bottom.The lower part is siliceous rock with a thickness of ca.180.1 m,which is dominated by siliceous rock,sandy mudstone and siltstone.The upper part is sandy mudstone with a thickness of ca.132.3 m,which is mainly composed of black shale,sandy mudstone and siltstone.The measured section is overlaid with stromatolite dolomite.The newly discovered black shale is located in the middle sub-member of the upper sand and mudstone section with a thickness of ca.60 m,organic carbon content(TOC)of 1.04%-4.81%,and it is developed in the reduction-sedimentary environment.The detrital zircon U-Pb ages of the siltstone in the lower section indicate that the maximum sedimentary age of this set of black shale is later than the late Neoproterozoic Tonian,and its formation may be related to the global glacial events.Accurate chronological data are not available for the newly discovered black shale,however,regional geological,stratigraphic contact relationships in the field,and newly obtained detrital zircon U-Pb ages support that the sedimentary age of the black shale was prior to the Cambrian.It may be a set of ancient hydrocarbon source rocks with good quality found in the periphery of the Tarim Basin.It is of great significance in oil and gas exploration and paleo-environment research,and the new findings will strengthen the confidence of the oil and gas exploration in the deep ancient strata of the Tarim Basin.
作者
李王鹏
王毅
钱一雄
邵志兵
储呈林
张仲培
李慧莉
杨伟利
LI Wangpeng;WANG Yi;QIAN Yixiong;SHAO Zhibing;CHU Chenglin;ZHANG Zhongpei;LI Huili;YANG Weili(Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 100083,China;Institute of Petroleum Geology,Petroleum Exploration and Production Research Institute,SINOPEC,Wuxi 214126,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2022年第4期533-547,共15页
Natural Gas Geoscience
基金
国家自然科学基金项目(编号:41902149,41702238)
中国石化科技部项目(编号:P17046-3,P21087-6)联合资助。
关键词
塔里木盆地
新元古代
古老烃源岩
深层
冰碛岩
Tarim Basin
Neoproterozoic
Ancient hydrocarbon source rocks
Deep strata
Diamictite
