摘要
根据研究区哲斯组的岩性特征、沉积构造特征，结合泥岩微量元素和饱和烃有机地球化学等地球化学参数，综合研究索伦地区哲斯组的沉积环境，进而解释海平面的相对升降，为研究区哲斯组油气地质条件评价提供依据。结果表明研究区哲斯组沉积环境的水体为半咸水，古盐度范围为18.55‰-28.72‰，古气候以温湿为主。B（硼元素）和微量元素比值Sr／Ba、B／Ga等可以反映的古盐度与古水深的变化，两者受海平面升降变化影响；利用定量计算的古盐度和反映古盐度的Sr／Ba值、B／Ga值和Rb／K值等编制了海平面相对变化曲线，显示研究区哲斯组剖面发生了2次海侵、海退沉积旋回，海侵发生在哲斯组底部和中部。据沉积相分析，结合地球化学指标V／（V＋Ni）值、稀土元素Ce异常值饱和烃气相色谱，表明研究区哲斯组主要为缺氧、还原的浅海陆棚沉积环境，该环境有利于有机质保存和烃源岩发育。
The sedimentary environment of middle Permian Zhesi Formation in the Suolun area was studied on the basis of lithology and sedimentary structure, the content and ratios of trace elements as well as geochemical parameters of saturated hydrocarbon, so as to discuss relative change of sea-level and the evidence for evaluation of oil/gas geologic conditions of Carboniferous-Permian. It indicates that the Zhesi Formation mainly belongs to marine sedimentary environment under the condition of warm-humid climate and semi-salt water, with the range of palaeosalnity from 18.55‰ to 28.72‰. The paleosalinity and the change of water depth are showed by the trace elements and their ratios, which are impacted by the change of sea-level. Palaeosalinity and relative change of sea-level has a good correlation with sedimentary facies evolution. Using the quantitative calculation palaeosalinity and the values which reflect the paleosalinity and the water depth of Sr/ Ba, B/Ga and Rb/ K , the curve of relative change of sea-level of Zhesi Formation was established. The Zhesi Formation had undergone two transgression-regression cycles, with the transgressions taking place in the bottom and middle part of Zhesi Formation. According to sedimentary facies analysis and the geochemical index, main body of Zhesi Formation was formed in an neritic shelf environment characterized by oxygen deficient and reductive conditions. This study is conducive to the preservation of organic matter and development of hydrocarbon source rock.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2015年第8期1484-1494,共11页
Acta Geologica Sinica
基金
中国地质调查局"天山-兴蒙构造带石炭-二叠系对比研究"项目(编号1212011120966)
国土资源部公益性行业科研专项项目(编号201311022)资助的成果
关键词
内蒙古东部
哲斯组
泥岩
地球化学
沉积环境
海平面变化
Eastern Inner Mongolia
Zhesi Formation
mudstone
geochemistry
sedimentary environment
sea-level changes
