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南黄海盆地勿南沙隆起古生界地层的地热和地球化学异常一直受到众多地质学家和地球化学家的关注。本文联用显微测温和激光拉曼光谱技术对南黄海盆地勿南沙隆起的常州(CZ)-2-1井二叠系栖霞组灰岩石英脉中的流体包裹体进行了详细研究。根据岩石学特征、室温下包裹体相态特征和成分差别,这些包裹体可以分成三大类六小类。流体包裹体拉曼光谱分析结果表明包裹体中含有甲烷和有机物,证明了该区曾经有含烃类流体活动。显微测温分析表明流体包裹体的均一温度在214℃～305℃之间,远高于该区正常沉积的盆地古地温,暗示包裹体捕获了热液流体。根据岩石学观察和测温分析结果,样品中主要存在三期流体包裹体,其均一温度和流体的甲烷浓度分别为:214℃,0.1347mol/L;265℃,0.1722mol/L;305℃,0.3370mol/L。包裹体甲烷浓度随均一温度升高呈增大的趋势。本次研究证实南黄海盆地勿南沙隆起区曾存在含烃热液流体活动,这些实验结果可以为合理解释热异常和地球化学异常提供证据。
The geothermal and geochemical anomalies of the Paleozoic strata in the upwelling of the No. Nansha Formation in the southern Yellow Sea Basin have been the focus of many geologists and geochemists. In this paper, the fluid inclusions in the limestone quartz veins of the Permian Qixia Formation in the Changzhou (CZ) -2-1 well in the southern South China Sea have been studied in detail by microscopic temperature measurement and laser Raman spectroscopy. According to the petrological characteristics, the phase characteristics and compositional differences of inclusions at room temperature, these inclusions can be divided into three categories and six subcategories. The results of Raman spectroscopy of fluid inclusions show that the inclusions contain methane and organic compounds, which proves that there was a hydrocarbon-bearing fluid activity in the area. Microscopic temperature analysis shows that the homogenization temperature of fluid inclusions is between 214 ℃ and 305 ℃, which is much higher than the paleo-geothermal temperature of the normal sedimentary basins in this area, indicating that the fluid inclusions have captured the hydrothermal fluid. According to the results of petrological observation and temperature measurement, there are mainly three stages of fluid inclusions in the sample, the uniform temperature and the methane concentration of the fluid are 214 ℃, 0.1347mol / L, 265 ℃, 0.1722mol / L, 305 ℃, 0.3370 mol / L. The concentration of methane in the inclusions tends to increase with increasing homogenization temperature. This study confirmed the presence of hydrocarbon-bearing hydrothermal fluids in the upwelling of the Nansha Basin in the southern Yellow Sea basin. These experimental results may provide evidence for the reasonable interpretation of thermal anomalies and geochemical anomalies.