北羌塘盆地晚中生代地层:早白垩世海相地层的发现  

Strata of the Late Mesozoic in the North of Qiangtang Basin: A Discovery of the Early Cretaceous Marine Strata

作　　者：朱丽霞[1] 谭富文[1] 付修根[1] 陈明[1] 冯兴雷[1] 曾胜强[1,2] 

机构地区：[1]成都地质矿产研究所,成都610081 [2]中国地质科学院,北京100037

出　　处：《沉积学报》2012年第5期825-833,共9页Acta Sedimentologica Sinica

基　　金：国家油气专项"青藏高原重点盆地油气资源战略调查与选区"(编号:XQ-2009-1);国家自然科学基金项目(批准号:40702020);四川省青年科技基金(编号:09ZQ026-006)资助

摘　　要：针对羌塘盆地是否存在早白垩世海相沉积,以那底岗日地区主干剖面为依托,结合胜利河、托纳木、长蛇山等已初步判断为早白垩世的油页岩剖面为辅助剖面,采用古生物化石定年和同位素定年相结合的研究方法,对胜利河—托纳木地区原初步定为晚侏罗世—早白垩世的海相地层时代作了进一步研究,结果表明,其时代为早白垩世。这些海相地层在胜利河—托纳木地区广泛分布,但岩性组合存在一定的差异,在胜利河—长蛇山地区为油页岩,厚度最大,向东逐渐变薄,过渡为页岩沉积,向西过渡为灰岩沉积。区域上该套地层对下伏油气藏的保存具有重要意义。In the Late Jurassic period, Qiangtang basin has experienced an obvious tectonic uplift and turned into a terrestrial basin. Most of the region has undergone erosion in the Cretaceous, which results in the lack of Lower Creta- ceous. Therefore, to confirm the existence of the Early Cretaceous marine sediments in the Qiangtang basin, this pa- per conducted a research on Shenglihe-Tuonamu region preliminarily judged as Late Jurassic-Early Cretaceous marine strata era, which is based on the Nadigangri section and combined with the Shenglihe, Tuonamu, Changsheshan sec- tions which are preliminary judged on the Early Cretaceous era oil shale formation on the auxiliary sections, with the adoption of paleontological fossils and isotopic chronology to judge the era of each formation of the section from the top to the bottom and rejudge the era of the Original Suowa formation. The results show that original Suowa Formation is in the Late Jurassic-Early Cretaceous, Suowa formation is in the Late Jurassic, Weimingming formation is in the Early Cretaceous, and Xueshan formation is in the Late Early Cretaceous-Early Late Cretaceous. The formation comparison show that the era which was initially judged as Late Jurassic-Early Cretaceous shale limestone-gypsum marine strata should be Early Cretaceous. In the Early Cretaceous period, Early Cretaceous marine strata are widely distributed in Shenglihe-Tuonamu region, lithology formations of which are different in different regions. This stratum is oil shale and the thickest in Shenglihe-Changsheshan region, which gradually becomes thinner along the east and transits into shale sediment, and into limestone sediment in the west. Regionally, the existence of the Early Cretaceous strata is important to the conditions of the underlying oil and gas storage.

关 键 词：羌塘盆地 胜利河—托纳木地区 早白垩世 地层对比 

分 类 号：P539[天文地球—古生物学与地层学]