Experimental study on water and water rock interactions in the mid-crust conditions and its significance

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	Experimental study on water and water rock interactions in the mid-crust conditions and its significance
	Zhang, RH (Zhang Rong-Hua)4; Zhang, XT (Zhang Xue-Tong); Hu, SM (Hu Shu-Min)
刊名	CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
	2010
卷号	53 期号:9 页码:2244-2256
关键词	Mid-crust Water-rock interaction Critical state Dissolution rate High conductive and low velocity zone Earthquake fluids
ISSN号	0001-5733
英文摘要	For purpose of understanding geophysical nature of the crust, e. g. high conductance-low velocity zone and earthquake sources in mid-crust, a lot of experimental studies on dry rock system were performed. As it is well known that fluids exist in the crust, so far a few experiments on rocks combined with water (water-rock system) have been done. This paper reports experiments on water rock interactions at elevated temperatures and pressures, and provides the data about fluid nature and dissolution rates of rocks in the mid-crust. The mid-crust is present in the depth of 10(15) to 25 km below surface. Even though the thickness of the crust is various everywhere, but the depths of the high conductance-low velocity zones at different locations are nearly the same. The temperature of top of the zone is about 300 degrees C, the bottom temperature is about 450 degrees C. We have been carrying out the kinetic experiments on water-rock interactions in the upper mid-crust conditions and study the nature of water and aqueous solutions in the critical and supercritical regions. Dissolution experiments of minerals (albite, actinolite, pyroxene, etc) and rocks (basalts, syenite and granodiorite) in aqueous solutions were performed at temperatures from 20 to 435 degrees C and at pressures of 23 to 35 MPa. Experiments found that the maximum release rates of silica in mineral or in rocks always occur at 300 to 400 degrees C. As water exists in the mid-crust and tectonic activities may cause faults, structure cracks, pressure decrease, and fluid flowing in the mid-crust, then aqueous solution in the mid-crust would be present in the sub-critical and super-critical states. Strong dissolving mineral and rocks, leaching silica, and breaking silicate network continuously happen, then leading to rock layer collapse. Those events will enhance fluid flowing. immiscibility field, the boiling will occur, earthquake, or earthquake fluids. Aqueous If fluids come to a sub-critical state, liquid-vapor and also a possible fluid eruption. This could induce solutions at temperature from 300 to 450 degrees C and fluids from the sub-critical to critical regions accompanied by strong water-rock interactions will show the high conductive-low velocity feature in the mid-crust.
学科主题	岩矿鉴定与测试
WOS关键词	SODIUM-CHLORIDE SOLUTIONS ; DIAMOND-ANVIL CELL ; SOUTHERN TIBET ; ELECTRICAL-CONDUCTIVITY ; SUPERCRITICAL WATER ; HIGH-TEMPERATURES ; IR SPECTROSCOPY ; HIGH-PRESSURES ; FLOW ; FLUIDS
WOS研究方向	Geochemistry & Geophysics
语种	中文
出版者	SCIENCE CHINA PRESS
WOS记录号	WOS:000282294600026
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/39147]
专题	中国地质调查局
作者单位	1.[Zhang Rong-Hua 2.Zhang Xue-Tong 3.Chinese Acad Geol Sci, Lab Geochem Kinet, Inst Mineral Resources, Beijing 100037, Peoples R China 4.中国地质科学院矿产资源研究所
推荐引用方式 GB/T 7714	Zhang, RH ,Zhang, XT ,Hu, SM . Experimental study on water and water rock interactions in the mid-crust conditions and its significance[J]. CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,2010,53(9):2244-2256.
APA	Zhang, RH ,Zhang, XT ,&Hu, SM .(2010).Experimental study on water and water rock interactions in the mid-crust conditions and its significance.CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,53(9),2244-2256.
MLA	Zhang, RH ,et al."Experimental study on water and water rock interactions in the mid-crust conditions and its significance".CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION 53.9(2010):2244-2256.