河南独山玉矿的成矿构造背景及成因.pdf

同济大学硕士论文:摘要河南南阳独山玉矿的成矿构造背景及成因摘要本文从区域大地构造学分析角度出发,综合运用矿物学、岩石学、结晶矿物学、矿床地质学、地球化学等的理论与方法,对河南南阳独山玉的成矿构造背景、矿床特征、,并进行了成矿预测. 研究表明,河南南阳独山玉矿是在华北板块、华南板块和其间秦岭洋板块间相互作用形成秦岭造山带的特殊大地构造背景下,构造、岩浆、变质作用等综合作用的产物,其矿床成因的基本过程是., 1、秦岭造山带在未发生碰撞造山之前,为一古大洋板块,即秦岭洋板块. 在秦岭洋板块形成和演化早期,火成活动频繁,这些火成活动形成包括橄榄质科马提岩和辉石岩、,华北板块和华南扳块相向运动,秦岭洋开始关闭,洋壳沉积物加厚,同时随着地幔岩浆分异作用的进行,其粘度加大,火成岩浆直接上升到洋底的通道被堵塞,深部岩浆房便开始分异出辉石、辉长和斜长岩浆,因而后期的火成活动便形成辉石、,、随着秦岭洋的逐步关闭,,,强烈的构造挤压和断裂作用使岩体发生破碎和磨细,并同时在热液作用下发生分异. 斜长石开始集中,,含矿(主要含斜长石)热液在辉石岩,,,从围岩中淋滤Ca、 Cr、Fe和Ti等主要元素和微量致色元素逐步增加,所以玉石颜色从无色一白色一绿色一紫色一蓝色等,斜长石的排号从An9广—Anloo. 3、由于燕山期花岗岩浆热液的进一步交代蚀变,部分钙长石蚀变成黝帘石,黑云母蚀变成白云母等. 关键词:独山玉,矿床,板块构造,动力变质,麋棱岩,热液 THE TECTONIC BACKGROUND AND GENESIS 0F DUSHAN JADE DEPOSIT Abstract From the aspect ofregional geotectonics,the tectonic background and genesis of Dushan Jade is studied in this paper by prehensive theories and methods of mineralogy,petrology,crystal mineralogy,deposit geology and on basis of this,the jade deposit—forming mode isestablished and new deposit ispredicted. Study shows that the Dushan Jade deposit isthe synthetic product of tectonic,magmatism and metamorphism with specific geotectonic background ofinteraction between Huabei Plate,Huanan Plate and Qinling orogenic belt. The basic processes ofdeposit forming are as belows: tothe collision and orogenic movement,Qinling orogenic beltwas a paleo—ocean plate which iscalled temporarily Qinling Ocean theearly stage ofQinling Ocean,volcanic activity was frequent and formed olivine komatiite, gabbro and pyroxenite;whereas thesubduction ofHuanan Plate toHuabei Plate,the Qinling Ocean closed with thickening of ocean deposits,and at thesame time magma inmantle differentiatedandviscosity resulted intube ofmagma as