地球内部高温超高压流体的水热金刚石压砧原位观测  

Fluids in Extreme Conditions of the Earth Interior:1.In Situ Observation of the High Temperature and Ultra-High Pressure Fluids by Using Diamond Anvil Cell

作　　者：张雪彤[1] 张荣华[1] 胡书敏[1] 

机构地区：[1]中国地质科学院矿产资源研究所,国土资源部成矿作用和资源评价重点实验室,地球化学动力学实验室,北京100037

出　　处：《地质学报》2016年第8期1846-1859,共14页Acta Geologica Sinica

基　　金：中国地质调查局项目(12120113101700);国土资源部项目20010302;安徽省公益基金项目2010-g-28;科技部项目2001DEA20023,2001DEA30041,2003DEA2C021,G1999043212;国家自然科学基金项目20373064;中央公益研究项目(K2007-1-13)的资助和支持

摘　　要：地球内部极端条件下流体原位观测实验研究有了巨大进展。使用金刚石压砧结合各种谱学方法及同步辐射光源技术,在高温超高压条件下原位直接测量水和水合物结构性质,已经获得关于地球内部流体的分子-原子尺度信息的新实验数据。本次研究通过金刚石压砧对高压(10GPa)和高温高压(800℃/3GPa)NaCl-H_2O和NaCl-D_2O-H_2O的红外谱原位直测,研究了高压和高温高压下水分子结构。发现高压高温水分子OH振动频率随温度升高向高波数变化,而且,在临界态区域时水分子间的氢键网络破坏。水分子OH振动频率随盐度升高向高波数变化。水分子的其它方式运动的频率也随温度改变。实验说明了水分子在极端条件下的结构和运动方式。地球内部由深到浅,不同深度上的流体性质不断变化,如水的密度、介电常数等物理参数随温度压力改变,水的性质在临界态会出现突变。这些变化可以用高压高温的水的各种谱学特征来表征。水的性质取决于水的分子结构(键态)、分子振动方式。在跨越临界区时的水性质异常涨落与水分子结构变化、分子振动形式变化和氢键网络破坏有关。高温超高压流体原位红外谱观测实验是从分子尺度认识地球内部流体性质。水分子尺度的信息有利于我们深入理解地球深部流体性质、活动及物质相互作用,有利于理解岩石圈和地球深内部过程。In situ observations of the matter in the earth interior under ultra high pressure and high temperature conditions by using hydrothermal diamond anvil cell connected to spectrometer and microscope, combined with synchrotron radiation technique, obtained new data and message of their molecular structures and natures in molecule and atom scale. The nature of earth fluids would be changed by the variations of the temperatures and pressures of their locations. It is well known that the properties of water in the critical region may show anomalies in many of its physical properties. For example, the density or dielectric constant of water may drop with increasing temperature. The molecule structures of aqueous solutions（NaCl H2O and NaCl D2O H2O） at high temperatures and pressures（800℃/3GPa and 25℃/10GPa） have been examined using diamond anvil cell in situ observation connected to FT IR spectrometer combined synchrotron radiation technique. The sharp and strong O H stretching vibration near the critical point of water proves the breakdown of the hydrogen bonding net work. Within and near the critical region, the rapid decrease in the dielectric constant of water is caused by the destruction of the hydrogen bond net work of the water molecules. O H vibration frequency increases with temperature,and also with increasing salinity. Experiments demonstrated that nature and structure of water （NaCl H2O） will change with temperature and pressure in the deep earth. Non hydrogen bonding of water would be predominated at high temperatures, which cause to form water clusters occurred at deep earth. As passing through the critical state,the anomaly properties of fluids will be caused by the variations of water molecule vibrations and hydrogen bond network broken at the critical state. In situ observations of the fluids in the earth interior under ultra high pressure and high temperature conditions by using hydrothermal diamond anvil cell will help us to understand the nature of the fluids,fuild rock in

关 键 词：地球内部 高温超高压 临界态 流体性质 分子谱 

分 类 号：P542.5[天文地球—构造地质学]