Review of Rare Earths and Fluid-Rock Interaction

As demonstrated by a great amount of geologic and experimental evidences, RE of rock systems may be mobilized during fluid-rock interaction when solutions are rich in F^-, Cl^-, CO3^2- , HCO3^-, CO2, HPO4^2- , HS^-,S^2- , SO4^2- , though little has been known about the mobilizing mechanism of these anions or ligands. The fractionation of RE resulted from hydrothermal alterations, i. e., fluid-rock interactions, are distinctive. One set of field data implies the preferential mobility of the LRE, while another set of field observations demonstrates the dominant mobilization of the HRE, and some theoretical prediction is not consistent with the field evidence. The Eu anomalies caused by fluid-rock interaction are complex and compelling explanation is not available due to inadequate experimental approaches. To know the exact behavior of RE during fluid-rock interaction and to solve the contradiction between some theoretical predictions and field observations, the following works remain to be done : ( 1 ) experimental investigations of RE mobility and fractionation as a function of fluid chemistry, e.g., the activity of F^-,Cl^-, CO3^2- , HCO3^-, CO2, HPO4^2- , HS^-, S^2- , SO4^2- , etc. ; (2) experimental determination of RE mobility and fractionation as a function of T, P, pH, Eh and water/rock ratios; (3) investigation of the mechanism and the controlling factors of RE partitioning between hydrothermal minerals and fluids. It was demonstrated that RE mobility is a potentially useful method for exploration.     

Behaviors of Rare Earths during Fluid-Rock Interaction and Its Significance of Geochemistry

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用数字化图像分析法确定岩石物性

分形与多重分形作为复杂性科学研究的手段之一, 已渗透到地球科学的各个领域, 在元素含量分布、矿床储量分布、岩石孔隙分布等方面都取得了良好的应用效果。碳酸盐岩储集层的结构分析是国内外学者广泛关注的热点问题之一, 传统研究方法已不足以描述碳酸盐岩储集层微观结构的复杂性特征。在选取鄂西渝东地区峡口和石柱两个剖面大三段、长二段、嘉三段不同层位和不同深度以及部分岩心样品基础上, 通过制作碳酸盐岩薄片, 拍摄微观孔隙裂隙的环境扫描电镜照片, 在MATLAB 平台下采用数字图像分析可以获取孔隙度、渗透率、形态参数等相关的统计数据。通过与实测的物性参数对比, 此方法切实可行, 具有传统实验方法无法比拟的优势。