海南岛抱板群岩石高温高压实验及金成矿机理探讨

STUDY ON THE EXPERIMENTATION OF BAOBAN GROUP UNDER HIGH PRESSURE AND HIGH TEMPERATURE AND THE METALLO-GENIC MECHANISMS OF GOLD DEPOSITS ON HAINAN ISLAND

高温高压实验岩石学是地质学、岩石学领域中的“硬科学”犤1999,王德滋,等犦。目前高温高压实验岩石学研究主要是针对单一岩石的熔化和融离实验,而针对多物源成因的花岗岩模拟其物源贡献大小的实验岩石学及同时发生的成矿作用研究基本上是一个空白。文章根据海南岛戈枕含金剪切带中元古代花岗岩的物源特征及与之有关的戈枕式金矿成因特点,通过高温高压实验岩石学模拟,初步探讨古中元古代抱板群岩石高温高压下的熔融行为及金的成矿机理。实验结果表明,具原地-半原地性质的中元古代花岗岩很可能是由6份(或4份)石英绢云母片岩+1份斜长角闪片麻岩、在压力为1.879～2.143GPa、温度849～901℃的条件下部分熔融形成的,部分熔融过程同时还发生了金的聚集和活化迁移。

Experimental petrology under high p ressure and high temperature is'forced science'in the fields of geology and petrology(Wang De-zi et al.,1999).At present,the study about experim ental petrology under high pressure and high tempera ture concentrates mainly on melting and parting from melting experi-mentation of single rock,but,it is s carce of experimentation in granite s with different origins and followi ng mineralization.According to the original characteristics of Mesoproterizoic granites in the Gezhen gold-bearing ductile zone on Hainan island and the formative features of the Gezhen typ e gold deposits relating to Mesoproterizoic granites,the auth or firstly researched melting behaviors of the Paleo-Mesoproterozoic B aoban Group and mineralization by means of simulation of experimental petrolo gy under high pressure and high temperature.The experimental resu lts show that Mesoproperizoic grani tes are probably composed of part melting of six shares(or 4shares)of quartz sericite schist with one sh are of amphibolitic gneiss under the pressure of 1.879-2.143GPa and the t emperature of 849-901℃,in the meant ime,activation,trans-portation and concentration of gold happened.