羌塘盆地结构构造与油气勘探方向  

Structures of the Qiangtang Basin and Its Significance to Oil-Gas Exploration

作　　者：吴珍汉[1] 高锐[2] 卢占武[2] 叶培盛[3] 陆露[1] 殷裁云[1] 

机构地区：[1]中国地质科学院,北京100037 [2]中国地质科学院地质研究所,北京100037 [3]中国地质科学院地质力学研究所,北京100037

出　　处：《地质学报》2014年第6期1130-1144,共15页Acta Geologica Sinica

基　　金：深部探测技术与实验研究专项青藏高原腹地地壳断面构造实验研究专题(编号SinoProbe-02-01-A);青藏高原地质矿产调查评价专项羌塘盆地油气地质构造保存条件研究项目(编号1212011221111);科技部国际科技合作重点项目2006DFB211330联合资助成果

摘　　要：羌塘盆地是我国陆域大型中生代海相沉积盆地，富含烃源岩，但结构构造非常复杂。结合野外观测及相关资料对地震反射剖面进行地质构造详细解释，良好地揭示了羌塘盆地结构和深部构造。羌塘盆地逆冲推覆构造延伸存在显著差别，北羌塘凹陷多格错仁逆冲推覆构造、阿木错逆冲推覆构造与南羌塘凹陷肖茶卡一双湖逆冲推覆构造、多玛一其香错逆冲推覆构造仅发育于盆地表层0～3kin深度范围，北羌塘凹陷龙尾错逆冲推覆构造、羌中隆起北缘逆冲推覆构造、南羌塘凹陷赛布错一扎加藏布逆冲推覆构造、拉萨地块北缘色林错逆冲推覆构造系统自地表向深部延伸深度超过6km，羌塘盆地深部还发育中生界底部逆冲系和基底逆冲系，伴有不同规模的褶皱构造。逆冲推覆构造形成活动时代包括晚白垩世、古近纪早期和古近纪晚期，晚白垩世与古近纪早期逆冲推覆构造运动导致构造隆升的裂变径迹年龄分别为87±5～75±4Ma、64±5～46±4Ma。经过多期逆冲推覆构造改造和褶皱变形，羌塘盆地中生界海相沉积地层与烃源岩显著增厚，为新生代晚期二次生烃及油气成藏提供了非常有利的地质构造条件；北羌塘凹陷发育万安湖向斜、半岛湖背斜、东湖向斜、阿木错向斜，南羌塘凹陷发育宁日圈闭、鲁雄错背斜、诺尔玛错圈闭、协德圈闭、崩则错圈闭，羌中隆起下伏侏罗系和三叠系烃源岩，色林错下白垩统下伏古近纪湖相沉积，这些构造部位都是油气勘探的重要靶区。Qiangtang basin is a large marine basin formed in the Triassic and Jurossic Periods with abundant hydrocarbon source rocks and very complicated structures. Seismic reflection together with field geological mapping reveal well deep structures of the Qiangtang Basin in northern Tibetan Plateau. The Duoge Coren Thrust （DCT） and Armu Co Thrust （ACT） in the Northern Qiangtang Depression and the Xiaochaka- Shuanghu Thrust （XST） and Doma-Qixiang Co Thrust （DQT） in the Southern Qiangtang Depression mainly formed in upper Qiangtang Basin with depth less than 3km. The Longwei Co Thrust （LCT） and Northern Central Thrust （NCT） in the northern Qiangtang, Saibu Co-Zajia Zangbu Thrust （SZT） in the southern Qiangtang, and Northern Silin Co Thrust （NST） in the northern Lhasa Block formed in upper crust with depth larger than 6km. And the Northern Bottom Thrust （NBT）, Southern Bottom Thrust （SBT） and Basement Thrust （BMT） formed below Triassic marine deposits of the Qiangtang Basin. Anticlines and synclines of different sizes formed widely along major thrust faults. Most thrust systems in Qiangtang Basin formed in Late Cretaceous, Paleocene-Early Eocene and Late Eocene-Oligocene. Fission track dating of apatites further indicate that uplift caused by regional thrust occurred in 87 5~75 4Ma,64 ±5-46±4Ma, respectively, during Late Cretaceous and Early Paleogene. Regional thrust and folding in Late Cretaceous-Early Tertiary leads to evident thickening of the Triassic and Jurassic marine strata and hydrocarbon source rocks, which provides favorite geological setting for hydrocarbon generation and oil- gas accumulation after intensive thrust stopped in Late Oligocene-Early Miocene. The Wananhu syncline, Baodaohu anticline, Donghu syncline and Armu Co syncline in the Northern Qiangtang Depression, together with the Ningri trap, Luxiongco anticline, the Norma trap, Xiede trap and Bengze Co trap as well as Triassic-Jurassic marine source rocks beneath thrust sheets of the Paleozoic basement ro

关 键 词：盆地结构 逆冲推覆构造 地震反射 油气资源 勘探靶区 羌塘地块 

分 类 号：P618.13[天文地球—矿床学]