海洋地质与环境重点实验室知识库

氯度是深海热液流体的重要指标之一，它对深海热液的深部相分离程度和水/岩石反应的过程具有指示意义。然而，原位准确测量深海热液流体的氯度仍然面临着挑战。被称为“分子指纹谱”的激光拉曼光谱技术可用于定性定量分析水溶液中的待测物质，具有快速无损、无需样品制备、采样灵活等优势，适用于开展实验室高温高压模拟研究和深海极端环境的原位探测工作。本文基于水的O-H伸缩振动峰，通过实验室模拟的手段建立了一个适用于测量高温溶液氯度的分段定量模型，并在深海原位得到了验证。综合以上研究可得到如下几方面的结论：
（1）在不同温度下，氯度对水的O-H伸缩振动峰的影响程度不同。在0-50°C的温度范围内，RSpeak1（强氢键峰频移）随着氯度的变化较大。在50-200°C的温度范围内，PAR（强氢键峰面积/弱氢键峰面积）随着氯度的变化较大。在200-300°C的温度范围内，F（频移参数）随着氯度的变化较大。
（2）根据温度划分区间建立适用于高温溶液的氯度定量模型。基于拉曼光谱的特征与水溶液氯度的关系可建立RSpeak1（强氢键峰频移）、RSpeak2（弱氢键峰频移）、PAR（强氢键峰面积/弱氢键峰面积）和F（频移参数）分别作为因变量的氯度定量模型。根据这四种定量模型在不同温度区间的函数特点可建立一个根据温度划分区间的分段函数氯度定量模型，其准确度为96.20%。与基于单一参数建立的氯度定量模型相比，该氯度定量模型的准确度提高了约4.83-12.33%。
（3）冲绳海槽中部的伊是名海洼（Izena Hole）的Jade和Hakurei热液区受到了相分离作用影响。该区域原位的拉曼光谱数据反演的氯度均高于周围海水的氯度，这与前人对此区域的研究结果十分吻合，表明了该区域有可能受到了相分离作用的影响。

The degree of chlorinity of deep-sea hydrothermal fluids is one of the important indicators of deep-sea hydrothermal fluids, and it is indicative of the deep phase separation degree of deep-sea hydrothermal fluids and the process of water/rock reaction. However, in-situ accurate measurement of the chlorination of deep-sea hydrothermal fluids still faces major challenges. The laser Raman spectroscopy technology, known as "Molecular Fingerprinting", can be used to qualitatively and quantitatively analyze the substances to be tested in aqueous solutions. It has the advantages of fast and non-destructive, no sample preparation, and flexible sampling. It is suitable for conducting laboratory high-temperature and high-pressure simulation research and deep sea In-situ detection work in extreme environments. In this paper, based on the O-H stretching vibration peak of water, a segmented quantitative model suitable for measuring the chlorinity degree of high-temperature solutions was established through laboratory simulation and verified in-situ in the deep sea. Based on the above research, the following conclusions can be obtained:
(1) At different temperatures, the degree of chlorinity has different effects on the O-H stretching vibration peak of water. In the temperature range of 0-50°C, RSpeak1 (frequency shift of strong hydrogen bond peak) changes greatly with the degree of chlorine. In the temperature range of 50-200°C, PAR (peak area of strong hydrogen bond/peak area of weak hydrogen bond) varies greatly with the degree of chlorine. In the temperature range of 200-300°C, F (frequency shift parameter) varies greatly with the degree of chlorine.
(2) Establish a quantitative model of chlorinity degree suitable for high-temperature solutions according to the temperature division interval. Based on the relationship between the characteristics of the Raman spectrum and the chlorinity degree of the aqueous solution, RSpeak1 (frequency shift of strong hydrogen bond peak), RSpeak2 (frequency shift of weak hydrogen bond peak), PAR (peak area of strong hydrogen bond/weak hydrogen bond peak area) and F can be established. (Frequency shift parameter) The chlorinity quantitative model as the dependent variable. According to the functional characteristics of these four quantitative models in different temperature intervals, a piecewise function chlorinity quantitative model can be established according to the temperature division interval, and its accuracy is 96.20%.Compared with the chlorinity quantitative model established based on a single parameter, the accuracy of the chlorinity quantitative model is improved by about 4.83-12.33%.
(3) The Jade and Hakurei hydrothermal areas of Izena Hole in the middle of the Okinawa Trough were affected by phase separation. The chlorinity retrieved from in-situ Raman spectroscopy data in this area is all higher than the chlorinity retrieved from the surrounding cold sea water, which is in good agreement with previous research results in this area, indicating that this area may be subject to phase separation.