Study on smectite-to-illite transformation mechanism

成功完成了利用Kakkonda地热田IT-2岩心样品对蒙脱石-伊利石转化机理的研究，并在国内外期刊上发表了5篇论文。今年，我们在Guadeloupe的Bouillante地热田进行了莫脱石到贝德尔石的转化，作为我们目前的蒙脱石到伊利石转化机制模型的应用。详细的XRD， FTIR和化学分析清楚地表明，随着深度和温度的增加，蒙脱土通过两层间的层结从蒙脱土转变为贝德尔石。然而，基于碳和氧同位素数据分析，这种转变不是由热控制的贝德尔化解释的，而是由与粘土降水相关的溶液组成控制的。从我们目前的蒙脱石-伊利石转化机制模型来看，这一结论是合理的。这一结果已提交给美国矿物学家与法国同事合著的一篇文章。下一步，了解粘土矿物在水岩相互作用中的降水动力学是很重要的。通过实验工作来了解硅酸盐离子在溶液中的行为是不容易的。因此，我们开始研究氢氧化铁矿物的结晶过程，特别是阴离子在FeOOH矿物形成中的作用，而不是硅酸盐的结晶。我们在这个课题上有了有趣的结果，并发表了两篇论文。

Study on smectite-to-illite transformation mechanism, using the core samples IT-2 from the Kakkonda geothermal field, has been successfully completed and the results have been published in five papers of international and national journals. In this year, we worked on motmorillonite-to-beidellite transformation at Bouillante geothermal field, Guadeloupe as an application of our current model of smectite-to-illite transformation mechanism. Detailed XRD, FTIR and chemical analyses clearly demonstrated a transition from montmorillonite to beidellite with increasing depth and temperature via interstratification of the two layers. However this transition was not explained by a thermally controlled beidellitization but control of solution composition related to the precipitation of clays, based on the carbon and oxygen isotopes data analysis. This conclusion is reasonably accepted from the viewpoint of our current model of smectite-to-illite transformation mechanism. This result has been submitted to an article of American Mineralogist co-authored with French colleagues.In the next step, it is important to understand the precipitation dynamics of clay minerals in water-rock interaction. It is not easy that experimental works undertakes to understand the behavior of silicate ions in solution. Instead of crystallization of silicates, thus, we started working on crystallization process of iron oxyhydroxide minerals, especially focusing on understanding of the role of anions in the formation of FeOOH minerals. We have interested results on this subject and published two papers.