崇安盆地粒状碎斑熔岩元素和同位素地球化学研究

ELEMENTS AND ISOTOPIC GEOCHEMICAL INVESTIGATIONS OF MORTOR LAVA IN CHONGAN BASIN

根据崇安盆地粒状碎斑熔岩的地质地球化学特征和水-岩氧同位素相互作用的研究,发现在盆地范围内粒状碎斑熔岩曾经历过不同程度的非平衡水-岩氧同位素交换。但是,除古楼-腾云尖、黎口和岚谷外,其他地区水-岩相互作用的规模都不太大。利用缓冲开放系统模式估计古楼-腾云尖一带粒状碎斑熔岩的水-岩相互作用持续时间 t/Ma 大约为0.42—0.44,石英与系统之间的氧同位素平衡程度接近0.125—0.130,相应的有效水-岩比大致为0.13—0.14。

Based on the studying in detail for the geological-geochemical characteristics and oxy- gen isotopic interaction between waters-rocks of mortor lava in Chongan basin,it is suggested that oxygen isotopic which are associated with waters-rocks interaction was exchange disequilibrium in various degree. Although,except the Gulou-Teng Yunjian,Likou and Langu,the scale of the interaction be- tween such waters-rocks of mortor lava in Chongan basin were prabally very litter.Using the mo del of buffered open system,it is estimated as about 0.42 Ma—0.44 Ma of time width for water- rock interaction,as about 0.125—0.130 the degree of oxygen isotopic equilibration of quartzs,as about 0.13—0.14 for effective water/rock ratios.