IOCAS-IR  > 海洋地质与环境重点实验室
深海热液喷口流体中溶解气体的激光拉曼光谱原位定量分析
Alternative TitleIn situ quantitative analysis of dissolved gas in deep-sea hydrothermal vent fluid based on Laser Raman spectroscopy
李连福
Subtype博士
Thesis Advisor阎军
2020-05-19
Degree Grantor中国科学院大学
Place of Conferral中国科学院海洋研究所
Degree Name理学博士
Degree Discipline海洋地质
Keyword热液系统 二氧化碳 甲烷 氢气 拉曼光谱 定量分析 原位探测
Abstract

深海热液系统每年向海水释放大量的气体组分,不仅为热液生态系统提供了能量来源,同时也会显著改变周围海水的化学组成和特征。由于热液流体严苛的温度、压力条件,使得难以直接获取高温喷口流体中气体组分的含量。而通过保压流体取样技术先采样后实验室分析的测量方式,不仅探测效率低下,也无法避免采样和样品处理过程中气体组分的损失,造成极大的测量误差。激光拉曼光谱测量技术因其非侵入、非破坏、无需样品前处理、快速检测等一系列优势非常适宜于深海热液高温喷口流体中气体组分的测量。本文通过深海原位探测结合实验室内高温高压模拟的手段建立了一套适用于热液流体中主要气体组分(H2CO2CH4)的拉曼光谱定量分析方法。基于此方法对冲绳海槽热液区的多个高温喷口的热液流体中气体组分进行了定量分析。综合上述研究得到以下几点结论:

1)水的OH伸缩振动谱带对温度、盐度的变化较为敏感,可用于热液流体的温度的反演。通过对比OH伸缩振动谱带反演的流体温度与温度传感器所测喷口处流体温度的差异,可以反映拉曼光谱测量时海水的混染情况。这可以为原位拉曼探测时热液探针的深海作业提供参考和指导。

2)通过高温、高压模拟实验建立的SO42-CO2CH4H2等组分的拉曼定量模型均表现为线性,且线性回归性均较好,适宜于深海热液高温喷口流体的原位拉曼光谱定量分析。经定量模型确定的SO42-的浓度可用于热液喷口流体中CO2CH4H2等气体组分的端元值浓度计算。

3)原位拉曼光谱的测量结果显示冲绳海槽热液区喷口流体普遍受到不同程度相分离作用的影响。由于相分离作用的控制,在较小区域内的不同喷口在气体组分的含量上有巨大差异。

4)同一热液喷口,原位拉曼光谱对CO2CH4的测量结果大约是传统保压方式测量的结果的1.54倍。这指示了由于测量技术的限制,热液系统释放气体的通量很可能被大大低估。高效率的原位拉曼光谱探测在热液系统释放气体组分通量的研究中具有突出优势。

5)在冲绳海槽的南部Yokosuka site热液区利用深海激光拉曼光谱测量技术不仅确定了热液流体中各气体组分的浓度,还识别出倒置湖内喷发物的相态。根据现有的数据可以推测低密度气态热液喷发系统在全球各种地质背景下广泛分布,其在流体化学和成矿过程上与正常热液系统有很大区别,在未来的研究中应给予更多关注。

Other Abstract

The deep-sea hydrothermal system releases larges number of gas species into the ocean every year, which not only provides an energy source for the hydrothermal ecosystem, but also significantly affects the chemical composition of the surrounding seawater. It is difficult to directly measure the gas content in the high temperature hydrothermal vent fluids because of their harsh temperature and pressure conditions. The detection efficiency of traditional analytical methods involving the collection of hydrothermal fluids using gas-tight samplers and the analysis in laboratory is low. In addition, the loss of gas components, resulting in great measurement errors, in the process of sampling and sample treatment is hard to avoid. Laser Raman spectroscopy is very suitable for the measurement of gas content in deep-sea hydrothermal vent fluids due to its non-invasive, non-destructive and rapid test capabilities as well as the benefit that sample preparation is often not required. In this paper, quantitative analysis methods of Raman spectroscopy for the H2, CO2 and CH4 in hydrothermal fluid were established through high-temperature and high-pressure simulation experiment in laboratory. The gas species of hydrothermal fluids at Okinawa Trough hydrothermal field were analyzed quantitatively based on these methods. Based on the above, the following conclusions can be drawn:

  1. The OH stretching band of water can be used to calibrate the temperature of hydrothermal fluid since it is sensitive to the changes of temperature and salinity. The mix proportion of hydrothermal fluids with seawater during Raman detection can be calculated by comparing the difference between the fluids temperatures measured by sensor at hydrothermal vent and derived from OH stretching band of water, which provides reference and guidance for the operation of in situ Raman spectroscopy.
  2. The Raman calibration models of H2, CO2, CH4 and SO42- established through high-temperature and high-pressure simulation experiments are linear and have good linear regression, which is suitable for in situ Raman spectroscopy quantitative analysis of hydrothermal vent fluid. The concentrations of SO42- determined by the quantitative calibration model can be used to calculate the endmember concentrations of H2, CO2, CH4 in the hydrothermal vent fluids.
  3. The results of in situ Raman detection showed that the hydrothermal fluid at the Okinawa Trough generally suffered from different degrees of phase separation. The content of gas in hydrothermal fluids varies greatly among different vents due to the impacts of subseafloor phase separation.
  4. The concentrations of CO2 and CH4 measured by Raman spectroscopy are approximately 1.5 to 4.0 times higher than those derived from gas-tight samples collected at the same time and vent, which indicates that the flux of gases released by hydrothermal systems is likely to be significantly underestimated due to the limitations of measurement techniques. In situ Raman measurement has a prominent advantage in the research of the gas flux released by hydrothermal system because of its high efficient detection capabilities.
  5. In the Yokosuka site hydrothermal field, in situ Raman measurement was used to determine not only the concentrations of the gas components in the hydrothermal fluid, but also the phase states of the emissions in the inverted lake. Available data suggest that this type of low density emanation hydrothermal system is broadly distributed in diverse geotectonic settings. Given the wide distribution of supercritical and vapor phase hydrothermal systems, the influence of low-density hydrothermal emanations on the recirculation of deep-sea hydrothermal systems and mineralization processes should be given more attention.
Subject Area地球科学
MOST Discipline Catalogue海洋科学
Pages169
Language中文
Table of Contents

目  录

第一章 绪论..... 1

1.1 选题背景与意义.... 1

1.2 研究现状分析.... 3

1.2.1 深海热液流体中气体组分的研究现状.... 3

1.2.2 深海激光拉曼光谱技术的发展现状.... 4

1.3 本论文的研究内容及章节安排.... 6

第二章 激光拉曼光谱技术及定量分析原理..... 9

2.1 激光拉曼光谱技术介绍.... 9

2.1.1 拉曼散射形成机制经典电磁理论.... 10

2.1.2 拉曼散射形成机制量子力学解释.... 11

2.2 拉曼光谱的特性与优势.... 13

2.2.1 拉曼光谱的特性.... 13

2.2.2 拉曼光谱的优势.... 14

2.3 激光拉曼光谱的定量分析.... 15

2.3.1 拉曼光谱定量分析的基本原理.... 15

2.3.2 内标峰的选择.... 16

2.3 小结.... 19

第三章 深海激光拉曼光谱探测系统与数据处理方法..... 21

3.1 深海激光拉曼光谱探测系统.... 21

3.1.1 拉曼插入式探针—RiPRaman insertion Probe)系统.... 21

3.1.2 深海极端环境模拟系统介绍.... 23

3.2 光谱数据采集与处理.... 28

3.2.1 原位拉曼光谱数据的获取.... 28

3.2.2 室内模拟实验的拉曼光谱数据的获取.... 28

3.2.3 拉曼光谱数据处理.... 28

第四章 热液流体的海水混染比例及气体组分端元浓度计算..... 29

4.1 原位拉曼光谱测量过程中热液流体与海水混染比例计算.... 29

4.1.1 实验材料与流程.... 31

4.1.2 水的OH伸缩振动峰随温度、盐度变化的特征.... 32

4.1.3 测温模型的建立.... 34

4.1.4 测温模型的验证与应用.... 37

4.2 热液流体中气体组分的端元值浓度计算.... 41

4.2.1 实验材料与流程.... 42

4.2.2硫酸根离子拉曼光谱定量模型的建立.... 42

4.2.3 硫酸根离子拉曼光谱定量模型的验证与应用.... 44

4.3 小结.... 45

第五章 氢气的原位拉曼光谱定性与定量分析..... 47

5.1 实验材料与流程.... 48

5.2 氢气的拉曼光谱定性分析.... 48

5.2.1气态氢气拉曼振动峰的特征.... 49

5.2.2 溶解态氢气拉曼振动峰的特征.... 55

5.3 溶解态氢气的拉曼光谱定量分析.... 57

5.4 小结.... 59

第六章 二氧化碳的原位拉曼光谱定性与定量分析及其应用..... 61

6.1 实验材料与流程.... 62

6.2 二氧化碳的原位拉曼光谱定性分析.... 62

6.2.1 气态二氧化碳的拉曼光谱特征.... 62

6.2.2 液态二氧化碳的拉曼光谱特征.... 64

6.2.3 固态二氧化碳的拉曼光谱特征.... 66

6.2.4 超临界态二氧化碳的拉曼光谱特征.... 66

6.2.5 溶解态二氧化碳的拉曼光谱特征.... 68

6.2.6 水合物态二氧化碳的拉曼光谱特征.... 68

6.3 溶解态二氧化碳的拉曼光谱定量分析.... 69

6.4 二氧化碳的原位拉曼光谱定量分析在冲绳海槽热液区的应用.... 72

6.4.1 原位探测区域地质背景介绍.... 72

6.4.2 原位拉曼光谱测量与保压流体取样.... 73

6.4.3 热液流体的原位拉曼光谱分析.... 74

6.4.4 原位拉曼光谱探测与保压流体取样方式测量结果的对比.... 76

6.5 小结.... 79

第七章 甲烷的原位拉曼光谱定性与定量分析及其应用..... 81

7.1 实验材料与流程.... 81

7.2 甲烷的拉曼光谱定性分析.... 82

7.3 溶解态甲烷的拉曼光谱定量分析.... 83

7.4 溶解态甲烷的原位拉曼光谱定量分析在冲绳海槽热液区的应用.... 85

7.4.1 原位探测区域地质背景介绍.... 85

7.4.2 原位拉曼光谱测量与保压流体取样.... 86

7.4.3 热液流体的原位拉曼光谱分析.... 87

7.4.4 原位拉曼光谱探测与保压流体取样方式测量结果的对比.... 93

7.4.5相分离作用对探测区域热液流体化学组分的影响.... 95

7.4.6 热液流体中CO2CH4扩散行为上的差异.... 97

7.5 小结.... 100

第八章 原位拉曼光谱测量技术在冲绳海槽南部热液区的综合应用..... 101

8.1 应用区域简介.... 101

8.2 现场实验过程.... 102

8.3 原位测量数据分析.... 103

8.4 Yokosuka site热液系统喷发模式的特征及其影响.... 106

8.5 小结.... 110

第九章 结论与展望..... 111

9.1 结论.... 111

9.2 存在的问题与展望.... 112

参考文献..... 115

附录1 CO2拉曼光谱定量模型实验数据..... 137

附录2 CH4拉曼光谱定量模型实验数据..... 141

附录3 H2拉曼光谱定量模型实验数据..... 145

附录4 SO42-拉曼光谱定量模型实验数据..... 149

..... 151

作者简历及攻读学位期间发表的学术论文与研究成果..... 153

Document Type学位论文
Identifierhttp://ir.qdio.ac.cn/handle/337002/164676
Collection海洋地质与环境重点实验室
Recommended Citation
GB/T 7714
李连福. 深海热液喷口流体中溶解气体的激光拉曼光谱原位定量分析[D]. 中国科学院海洋研究所. 中国科学院大学,2020.
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