流体的氯含量及其演化:来自岩石含氯矿物的记录

Chlorinity and its variations in fluids revealed by chlorine-bearing minerals of rocks

含氯流体是地质作用中重要的流体形式之一。通过含羟基矿物的氯含量来反演流体的组分及其演化是流体研究的一个重要方面。角闪石、黑云母、方柱石和磷灰石是主要的含氯矿物,可以揭示含氯流体与岩石的相互作用。这些矿物的氯含量受平衡流体的成分、温压条件以及自身的晶体化学结构等复杂因素制约。一方面,结合实验确定的热力学数据可以通过矿物氯含量在一定范围内定量计算流体的氯组分;另一方面,也可以根据矿物的氯含量变化特征来反演流体-岩石相互作用过程中流体成分的变化特征,这样的流体成分演化可能反映了特定的地质过程。

The chlorine-bearing fluid is an important fluid form in the geological process.It is a significant aspect for us to study the composition and evolution of fluid by the chlorine content in OH-bearing minerals.Amphibole,biotite,scapolite and apatite are main Cl-bearing minerals that can be used to unravel Cl-bearing fluid-rock interaction.The chlorine contents in these minerals are the functions of fluid compositions,P-T conditions and the crystal-chemical structure of minerals.The Cl concentration in a fluid can be estimated on the basis of the Cl contents in minerals and their thermodynamic data,and on the other hand,the variation of Cl content in minerals also reflects the Cl change in fluid during the process of fluid-rock interaction,which probably is correlated with unique geological processes.