摘要
作为流体作用过程中水岩反应的产物 ,粘土矿物可以帮助人们认识水岩反应的机制和流体活动的特征。本文以江西金山金矿为例 ,通过对热液蚀变粘土矿物伊利石和绿泥石结晶度、平均结晶大小和晶格应变的测定 ,讨论了岩石变形对伊利石和绿泥石结晶生长差异的影响。在岩石应变较弱、水 /岩比较小的糜棱岩带 ,伊利石的平均结晶大小与结晶度成负相关 ,而在岩石应变较强、水 /岩比较大的超糜棱岩带 ,绿泥石的平均结晶大小与结晶度成正相关。由应变较弱的蚀变糜棱岩带到应变较强的蚀变超糜棱岩带 ,伊利石的结晶度有变小的趋势 ,而绿泥石的结晶度则基本保持不变。认为在成矿流体作用过程中 ,粘土矿物的形成和特点不仅受水 /岩比的影响 ,而且在岩石变形过程中 ,岩石的应变和恢复速率也影响粘土矿物的结晶大小 ;伊利石和绿泥石平均结晶大小与其结晶度之间的关系可以反映岩石变形的机制和行为。
Being products of water-rock interaction during the migration of fluids, clay minerals can help us to understand the mechanism of water-rock interaction and features of fluids. With the Jinshan gold deposit in Jiangxi Province as an example, the authors determined the crystallinity, mean crystal size and lattice strain of illite and chlorite and, on such a basis, discussed the difference of crystallinity, mean crystal size and lattice strain between illite and chlorite caused by deformation of mylonite and untramylonite. There exist strong negative correlation between crystal size and crystallinity of illite in altered mylonite of low strain and low water/rocks ratios, and positive correlation between crystal size and crystallinity of chlorite in altered untramylonite of high strain and high water/rocks ratios. From altered mylonite to altered untramylonite, the crystallinity of illite decreases whereas that of chlorite shows no obvious variation with the increasing strain. It is held that the formation of clay minerals is affected not only by water-rock interaction but also by the strain rate and recovery rate during rock deformation. The relationship between crystallinity and crystal size of illite or chlorite can reflect the behavior and mechanism of deformed rock.
出处
《岩石矿物学杂志》
CAS
CSCD
北大核心
2003年第3期265-272,共8页
Acta Petrologica et Mineralogica
基金
国家基础研究重点规划资助项目 (G19990 432 0 0 )
关键词
成矿流体
粘土矿物
伊利石
绿泥石
岩石变形
结晶度
应变速率
金山金矿
ore-forming fluid
clay mineral
illite
chlorite
rock deformation
crystallinity
strain rate
Jinshan gold deposit
