H2O-NaCl-CO2体系流体包裹体拉曼光谱定量研究

Geological fluid plays an important role in Earth evolution and geological mineralization, which can be preserved as fluid inclusions. Therefore, fluid inclusions have been attracting much attention. Because the ternary H2O-NaCl-CO2 system is recognized to be a typical model of fluid inclusion, it is very important to study the H2O-NaCl-CO2 ternary system. Quantitative chemical analyses of fluid inclusions have been proven to be important in the interpretation of many processes in diagenesis, metamorphism, and hydrothermal deposition of ore minerals. To characterize the properties of this fluid, microthermometry has been applied as a routine method. However, for H2O-NaCl-CO2 system, microthermometry overestimates the salinity because water molecules are incorporated into the carbon dioxide clathrate structure. Raman spectroscopy is an efficient non-contact and non-destructive method, and is widely employed in single fluid inclusion. So far, many works have been conducted on H2O-NaCl-CO2 system. These greatly enhance our understanding on the system. However, only a few works have been reported on quantitative study on H2O-NaCl-CO2 system. So far, there is no widely accepted solution for Raman quantitative study on H2O-NaCl-CO2 system. To our knowledge, this may be due to the deficiency in understanding the Raman quantitative approach. The Raman intensity can be expressed as R∝nI, where R is Raman intensity, n is Raman active molecular number, I is the intensity of excitation radiation. It seems that the Raman quantification should be straightforward. However, the Raman intensity depends not only on the analyte concentration but also on the intensity of the incident light, which is closely related to measurement conditions such as the power of the excitation source, the instrumental optical configuration, and sample alignment. Therefore, the Raman intensity cannot be directly applied to measure analyte concentrations. From our recent work, Raman quantitative study should be based on relative intensity, which is different from other analytical methods. In this work, Raman spectroscopy is employed to quantitatively study the H2O-NaCl-CO2 system, to respectively determine the NaCl concentrations (salinity) and CO2 molar fraction. From this, according to Raman study, it is feasible to quantitatively study H2O-NaCl-CO2 system. This provides the basis to correctly understand the physical and chemical behaviors of geological fluid and its role in geological evolution.

应用金刚石压腔（DAC，Diamond Anvil Cell）实验技术并结合石英裂隙愈合法合成流体包裹体的实验方法，研究Raman光谱与H2O-NaCl-CO2体系组分之间的定量关系，以便定量确定该体系的化学组成：[1] NaCl含量（盐度）；[2]CO2摩尔分数。该研究成果可以应用于Raman光谱对单个H2O-NaCl-CO2体系流体包裹体进行定量分析和研究，为理解地质流体在地质演化过程中的物理化学行为及其作用提供依据，促进流体包裹体Raman光谱定量化研究的进展。

应用金刚石压腔（DAC，Diamond Anvil Cell）实验技术并结合石英裂隙愈合法合成流体包裹体的实验方法，研究Raman光谱与H2O-NaCl-CO2体系组分之间的定量关系，以便定量确定该体系的化学组成：[1] NaCl含量（盐度）；[2]CO2摩尔分数。该研究成果可以应用于Raman光谱对单个H2O-NaCl-CO2体系流体包裹体进行定量分析和研究，为理解地质流体在地质演化过程中的物理化学行为及其作用提供依据，促进流体包裹体Raman光谱定量化研究的进展。