石油实验地质2017，Vol.39Issue(1)：24-31,8.DOI:10.11781/sysydz201701024
鄂尔多斯盆地中央古隆起区中寒武统鲕粒碳酸盐岩
Middle Cambrian oolitic carbonate rocks in the central ancient upwelling area, the Ordos Basin
摘要
Abstract
Middle Cambrian oolitic carbonate rocks were deposited in small shoals of the ramp in a central ancient upwelling area in the Ordos Basin. The oolitic carbonate rocks mainly consist of calcites and dolomites. The δ18 O and δ13 C values range from -11.3‰to -4.9‰and from -1.7‰to 0.3‰, averaging -6.5‰and -0.8‰V⁃PDB, respectively. Since they were deposited in oolitic shoals under meteoric leaching and experienced deep burial dia⁃genesis, the δ18 O values of the oolitic carbonate rocks are obviously low. During diagenesis, the influence of organic materials was slight, leading to normalδ13 C values for the oolitic carbonate rocks. Theδ18 O values of dolomites are higher than those of limestones. The results of analyses by laser⁃microsampling indicate that the δ18 O and δ13 C values of ooids are lower than those of the cements because the ooids formed in turbulent environments, and were leached by meteoric water after their formation. The cements precipitated in pore water with marine characteristics and high salinity, and were slightly influenced by meteoric water after their formation. The oolotic carbonate rocks are characterized with low Na and Sr, very high Fe, and medium Mn contents because of deep burial diagenesis. Most dolomites with low order degrees and high MgCO3 contents generally formed through replacement in brine during the burial stage. Deep burial diagenesis and good development of cements resulted in the development of ex⁃tremely low porosity in the oolitic carbonate rocks.关键词
岩石学特征/地球化学特征/鲕粒碳酸盐岩/中寒武统/中央古隆起区/鄂尔多斯盆地Key words
petrologic characteristics/geochemical characteristics/oolitic carbonate rock/Middle Cambrian/central ancient upwelling area/Ordos Basin分类
能源科技引用本文复制引用
徐波,王宝清,孙六一,王红伟,刘宝宪,井向辉,刘丽萍..鄂尔多斯盆地中央古隆起区中寒武统鲕粒碳酸盐岩[J].石油实验地质,2017,39(1):24-31,8.基金项目
国家自然科学基金项目（51574194）和国家科技重大专项（2016ZX05011－002）资助。 （）
