江西相山铀矿田中断裂与水相变耦合成矿——以邹家山矿床铀成矿作用分析为例

Mineralization and Fracture-Water Phase Transition Coupling in the Xiangshan Uranium Ore Field,Jiangxi

在已知成矿带和矿床中,随着找矿和开采的进行,已有的和新发现的资料积累越来越多。一个好的成矿理论,可以给这些资料较为统一的、合理的解释,还可能为老矿区(带)的深部和外围找矿指出一些新思路和新标志。据热液矿床水相变控矿理论,水相变可导致水的物理化学性质突变,使成矿物质被释放而成矿,在热液成矿作用中断裂降压引发水相变,是热液成矿作用的必要条件,断裂与水相变耦合是认识热液成矿作用的关键。基于上述目的和思路,本文以邹家山热液铀矿床为例,在综合前人研究成果的基础上,重点介绍了该矿床物质组成及含矿断裂特征方面近期研究成果,用热液矿床水相变控矿理论,分析了邹家山铀成矿作用过程,并初步探讨了相山矿田及华南铀热液成矿作用。指出在相山等华东南的铀矿田中,常见先形成X节理,后在力偶作用下沿X节理的一枝发生一组平行滑动,形成间断、侧列、菱形的张性小断块,从而出现总体挤压、局部拉张降压的环境,压力降低引发水相变而使成矿物质沉淀成矿。

As exploration and mining proceed in metallogenic belt and deposits,a lot of new information and data about the mineralization will continuously be accumulated.It is necessary to give a more unified and rational explanation for these new material.A good metallogenic theory can even tell us some new ideas and exploring indicators about the deep and surrounding prospecting in the known metallogenic belt and deposits.In theory of water phase controlling hydrothermal mineralization（WPCHM）,the phase transition of water can cause the sharp variations of the physicochemical properties of water,in which the mineralization matter can be released to form hydrothermal deposit.The pressure decrease in fracture is essential to induce water phase transition.Therefore,the coupling of water phase transition and fracture is a key to understand the hydrothermal mineralization.Based on the theory,taking the Zoujiashan hydrothermal uranium deposit as an example and combining with previous researches,this paper introduces firstly the recent researches on the ore compositions and characteristics of ore-bearing faults.Then,with the theory（WPCHM）,the paper discussed the uranium mineralization processes of the Zoujiashan hydrothermal uranium deposit,the Xiangshan ore-field,and Southern China uranium province.From these studies,the paper indicated that in the Xiangshan uranium ore-field and Southern China the X-conjugate joints are often firstly formed,then a set of parallel slips occur later along one direction of the X-joints to form some intermittent diagonal rhombic small blocks of extensional environment.So the slipping fractures are allover compression environment except extensional rhombic blocks.The extensional blocks reduce the pressures which are so low that induce water phase transitions,and during the processes,the ore-forming material in the hydrothermal fluid are released to form uranium deposits.