【作者】 肖万生；

【导师】 张惠芬； 翁克难；

【作者基本信息】 中国科学院广州地球化学研究所 ， 矿物学， 2001， 博士

【摘要】 地球深部存在烃类物质是客观事实，但对于其形成机制仍有不同的观点。本论文以温度、压力为主线，吸收了有关超临界水行为研究的最新成果，把地球内部成烃机制研究、地幔流体研究有机地结合在一起，提出地球内部含碳物质与水（含水矿物）反应生烃这种新的成烃机制，强调压力的作用和水的参与有利于烃类物质的形成和保存。为验证这一观点，本论文以金刚石压腔装置为手段，开展了地幔温压条件下（直到地球内部200km的深度）含碳物质与水反应生烃的模拟实验研究。实验过程中观察样品的变化、高压原位测定样品荧光光谱变化、Raman光谱和红外光谱特征，结果显示有烃类和CO₂形成。为对实验生成的微量气相产物进行气相色谱分析，设计了独具特色的取气样方法。气相色谱分析结果表明，含碳物质与水（含水矿物）在高温高压下反应，均生成了以CH₄为主的烃类气体，并伴有CO₂等，表明H₂O可参与成烃反应，为烃类形成提供氢源，为CO₂形成提供氧源。此外，水在成烃反应中可降低反应所需活化能，对破坏石墨（六方碳环）、碳化硅等的共价键起了重要作用。对实验中的有关化学反应进行热力学探讨，表明压力有利于提高烃类物质的稳定性，在高压下CH₄与CO₂能稳定共存。这些计算结果大多与我们的模拟实验相符，但不能解释不含变价元素的碳酸盐与水反应成烃的实验结果。地幔温压条件下含碳物质与水（含水矿物）反应成烃这种机制，可用于解释地球深部研究中发现的一些现象，并可为地球科学其它重大问题的阐述，如火山、地震等灾害的发生机制，提供新的思路。更多还原

【Abstract】 Wansheng Xiao ( Mineralogy ) Directed by Prof. Huifen Zhang and Prof. Kenan WengAlthough the fact that hydrocarbon exists in the Earth’s interior has widely been accepted, various kinds of standpoints still exist on its formation mechanism. On the basis of up-to-date achievements on the nature and behavior of supercritical water, this thesis combines the research of hydrocarbon formation mechanism in deep Earth with the study of mantle C-O-H fluids, and puts forward a new hypothesis that carbon-containing materials react with water to form hydrocarbon in deep earth. The author highlights the point that higher pressure and the existence of water are favorable for the formation and preservation of hydrocarbon. To verify this new mechanism, experimental research has been carried out on the reactions of carbon-containing materials with water to form hydrocarbon under mantle conditions with the pressure and temperature up to these in 200 km depth using diamond anvil cell (DAC). In the experimental process, changes in the samples were observed and photographically recorded using microscope, fluorescence spectrum, Raman spectrum and infrared absorption spectrum of the reacting systems were also determined in situ under high pressure. The results show that CH4-dominated hydrocarbons were produced along with CC>2 and sometimes, with other gases. In order to analyze the compositions of the trace gases produced in the experiments, this thesis designed a special sampling method for the DAC apparatus so that the gas samples could be measured using chromatography. All experimental results ofcarbon-containing materials-FkO systems at high pressure and temperature indicate that H2O participates in the hydrocarbon formation reactions, which provides hydrogen to form hydrocarbons and provides oxygen for CCh. Besides providing hydrogen resource to form hydrocarbons, H2O lowers the activation energy in the hydrocarbon formation reactions and plays a key role to destroy carbon rings, Si-C, and other covalent bonds in graphite (also aromatic hydrocarbons), moissanite and other minerals. Thermodynamic calculation results of some hydrocarbon formation reactions suggest that, higher pressure is favorable for the stability of hydrocarbon, and CO2 coexists stably with CRt under high-pressure conditions. Most of these calculation results are in agreement with the experimental results, but it can’t explain the experimental results of calcite reacting with water to form hydrocarbons. This new kind of hydrocarbon formation mechanism of carbon-containing materials reacting with water or water-containing minerals under the Earth’s mantle conditions can also improve our understanding of some phenomena in deep Earth, and provides a new path or idea to the exploration of some significant Earth scientific problems, such as the genesis of volcano, earthquake and other geological catastrophes.更多还原