浙江地开石粘土的氢、氧同位素组成及其形成条件

Hydrogen and Oxygen Isotopic Compositions of Dickite Clay and Their Forming Condition in Zhejiang Province

报道了浙江7个地开石粘土矿床的氢和氧同位素分析数据。应用水-岩石同位素交换作用的基本原理和方法,探讨这些矿床的同位素地球化学特征及其形成条件。同位素交换平衡曲线表明,成矿热液流体起源于中生代大气降水,在300℃的较高温下与围岩发生同位素交换后形成环流地热水;而地开石粘土是在250～100℃的中低温阶段酸性火山岩的热液蚀变产物。此外,还概述了地开石粘土的成矿热液体系从酸性偏还原环境到微酸性氧化环境的演化过程。

The data of hydrogen and oxygen isotopic analyses are reported in 7 dickite clay deposits of Zhejiang Provine. The isotopic-geochemical characteristics of these deposits and their forming condition are discussed by means of the funda- mental principle and method of the water-rock isotopic exchange reaction. The curves of isotopic exchange equilibrium show that the minerogenic hydrothermal fluid originated from the Mesozoic meteoric water, which formed cyclical geo- thermal-water after undergoing isotopic exchange with wall rock at higher temperature of 300℃. Dickite clay was the product from hydrothermal altera- tion of acidic volcanic-rocks at meso-low temperature stage of 250～100℃. In addition, the evolutional process of minerogenic hydrothermal system from the meta-acid reducing environment to the weak-acid oxidizing environment is described.