Experimental Observation of the Ore-Forming Fluid NaCl-H_2O System in the Earth Interior

作     者：ZHANG Ronghua and HU Shumin Open Research Laboratory of Geochemical Kinetics, Chinese Academy of Geological Sciences,26 Baiwanzhuang Road, Beijing 100037, China 

作者机构：Open Research Laboratory of Geochemical Kinetics Chinese Academy of Geological Sciences 26 Baiwanzhuang Road Beijing 100037 China 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：1999年第73卷第1期

页      面：47-64页

核心收录：

学科分类：070904[理学-构造地质学] 0709[理学-地质学] 07[理学] 

主　　题：critical phenomenon solution structure of the two-phased immiscible region ore-forming hydrothermal solutions 

摘      要：The NaCl-H_2O binary system is a major component of solutions coexisting with ores. Observation ofsaturated solutions of NaCl-H_2O by using the method of hydrothermal diamond anvil cell (HDAC) is a new approach tothe study of ore-forming fluids. The salinities of NaCl-H_2O solutions in experimental observation are in a range of 32-55%. The observed temperature range is 25℃-850℃, and the pressure range 1 atm-10 kb. In this temperature-pressure range, the supercritical single phase, two phases (L,V) close to the critical state and two-phased (L+V) immis-cible region were observed. And for the salinity of 35% the two phase L+V immiscible region of NaCl-H_2O solutionwas observed in a range of 253-720℃. Another temperature range, 400-817℃, was observed for the immiscible two-phased region of 50% salinity solution. In the high-temperature part of the two-phased immiscible region, the phase na-ture is very unstable. A critical phenomenon was observed when the heating path was very close to the critical *** is possible to observe a critical phenomenon : an explosion occurred almost constantly at the interface between theliquid and vapour and the interface is rather obscure. A continuous transition between phases L and V could be foundin the immiscible L+V phase while heating continuously. Moreover, as the NaCl-H_2O solution was separated into liq-uid and vapour phases, static charges surrounding each vapour bubble could be seen, and these bubbles were attractedtogether by the static charges to form a special solution structure. Besides, critical states of different salinities of NaCl-H_2O were observed in order to study the properties of the fluids occurring in the rocks in the earth interior, the origin ofore-bearing fluids and the significance of supercritical fluid with respect to the ore formation. The comparison of the sa-linity data of the fluid inclusions in the minerals of ore deposits with observations of NaCl-H_2O under HDAC in theconditions of high temp