红石泉铀矿床黑云母与晶质铀矿同步富集作用探讨

红石泉铀矿床是以岩浆气成热液成矿作用占主导地位的复成因型铀矿床。研究结果表明,黑云母的结晶时间明显晚于伟晶状白岗岩中的长石、石英等主要造岩矿物,这是由白岗质 岩浆本身的物质成分和物理化学条件所决定的。岩体边缘的黑云母与晶质铀矿同步富集作用是以元素地球化学和矿物热力学作用为主导的地质作用。黑云母与晶质铀矿结晶时间相近,具有一定的成因联系,并且,其组份具有明显的亲缘性是二者密切共生的原因。

A Tentative Discussion on the Synchronous Enrichment of Biotite and Uraninite in the Hongshiquan Uranium Deposit

The Hongshiquan uranium deposit is a new type uranium deposit recently discovered in China, The host rock-pegmatitic alaskite intruded into metamorphic rocks of the Lower proterozoic Longshoushan Group.The deposit is a polygenetic one formed as a result of composite metallization of magmatic pneu-mato- hydrothermal solution and late ore-bearing hydrothermal solution with the former playing the leading role. From the relationship between the activity of biotite in the magma and the crystallization temperature (T),i.e., Lna it is considered that the phenomehon that the biotite along the margin of pegamatitic alaskite crystallized obviously later than such rock-forming minerals as feldspar and quaT-tz is attributed to the comparatively small activity of biotite in the alaskitic magma which resulted in the decrease in its crystalliz}taon tempe- ra1ure until its crvstalliza1ion in the maamatic nneumatolvto-hvdrothermal stage. The synchronous ernichment of biotite and uraninit is a geological activity with crystallization differentiation of magma,element geochemistry and thermodynamic effects being dominant.According to thermodynamic principles and statistics, the authors consider the reasons for the intimate relationship between hiotite and uranirite to be as follows;(1)their close crystallization time,(2) the existence of certain genetic relationship and(3 ) the apparent affinity of hiotite and urauirite in composition, The syxtchronous enrichment of binti1e and uraxeinite depended on composition and physical-chemical conditions of the magma. It is therefore concluded that the biotite concentration zones aloaig the margin of the pegmatitic alaskike are favorable oro-prospecting places.