海相油气地质2017，Vol.22Issue(4)：85-93,9.DOI:10.3969/j.issn.1672-9854.2017.04.011
鄂尔多斯盆地中东部奥陶系马五5亚段白云岩地球化学特征及成因模式
Geochemical Characteristics and Genetic Model of Dolomite in Majiagou Submember-55 of Ordovician in East-Central Ordos Basin
摘要
Abstract
Based on the cores, thin sections and experimental data of dolomite in Majiagou Submember-55 of Ordovician in east-central Ordos Basin,it is shown that the value of carbon isotope of dolomite is the same as micritic limestone, ranging from -1.40℅ to 0.14℅, within the distribution of Ordovician sea water. The value of oxygen isotope of dolomite ranges from -7.51℅ to -5.98℅ which is heavier than that of micritic limestone, but lighter than that of Ordovician sea water. The REE distribution pattern of dolomite is the same as that of micritic limestone which is characteristic of LREE enrichment and HREE depletion. Combined with the ancient climate, sedimentary patterns and sea level changes, the results are obtained as follows: ①The dolomite is mainly formed by the seepage reflux dolomitization and partly by the evaporation pump dolomitization; ②Dolomite developed widely in the higher terrain such as Central Uplift-Jingxi Flat and Jingdong Uplift during the regressive period, which is controlled by the sea-level eustacy and palaeogeomorphology; ③The dolomite fabrics is related with its depositional settings. Micrite dolomite widely developed in Central Uplift-Jingxi Flat and Jingdong Uplift, grain dolomite and micrite dolomite with gypsum scattered in the Central Uplift-Jingxi Flat, and calcite micrite dolomite and dolomite micrite are mainly distributed in the central depression and edge zones.关键词
鄂尔多斯盆地/奥陶系/地球化学特征/沉积古地貌/海平面变化/白云岩Key words
Geochemical characteristics/Sedimentary patterns/Sea level change/Dolomite/Ordovician/Ordos Basin分类
能源科技引用本文复制引用
于洲,丁振纯,吴东旭,魏柳斌,魏源..鄂尔多斯盆地中东部奥陶系马五5亚段白云岩地球化学特征及成因模式[J].海相油气地质,2017,22(4):85-93,9.基金项目
本文受国家科技重大专项"大型油气田及煤层气开发"(编号:2011ZX05004-002)和中国石油天然气股份有限公司重大科技专项"深层油气勘探开发关键技术研究"(编号:2014E-32)联合资助 （编号:2011ZX05004-002）
