西成铅锌矿化集中区热水沉积成矿作用的岩矿证据

热水沉积成矿与正常沉积矿床在矿质来源和成矿机制上有很大的差异 ,反映在岩矿石结构构造上也有明显的差异性。虽然都有特征的沉积韵律条带、纹层构造 ,但由于热水沉积成矿矿质浓度大而形成了稠密而富集的组构 ,二者可区分。通过对西成铅锌矿化集中区两类热水沉积矿床的岩矿石组构进行论证 ,认为他们不但以上述特征区别于正常沉积矿床 ,而且各自也有差异 ,厂坝式矿床在组构上保留了原始沉积富而大的特点 ,虽有矿物粒度在变质作用中重结晶加粗的富集过程 ,但没有完全破坏原始的热水沉积构造。毕家山式矿床也具有原始沉积特点 ,但在改造过程中有热液叠加交代充填的现象 ,而原始沉积特点则又可区别于热液矿床 ,硅质岩的结构构造就是明显的证据。

ROCK AND ORE EVIDENCE OF THERMAL-WATER-SEDIMENTARY METALLOGENESIS IN XI-CHENG LEAD-ZINC METALLOGENIC PROVINCES

There is a great difference not only between thermal water sedimentary deposit and sedimentary deposit from original material of ore and metallogenesis,but also ore texture of them .Though thermal water sedimentary deposit ore and sedimentary ore of texture both have feature of banded structure cyclothem,striatus texture,thermal water sedimentary deposit ore has dense texture which formed from thermal source material. So we can discriminate it from sedimentary deposit. The parts is mainly discuss ore textural feature in Xi Cheng lead zinc metallogenic provinces,thought all deposit in Xi Cheng lead zinc metallogenic provinces ore area difference from sedimentary deposit not only ore textural but also deposit feature of them, for example, original texture of thermal water sedimentary deposit is not disturb though grain size of ore has been recrystallized, original texture has been left in Changba type lead zinc deposit,Bijiashan type lead zinc deposit has been metamorphosed and refiled by hydrothermal materal,but original ore texture of thermal water sedimentary has been left and we can discriminate it from thermal deposit,evidence is siliceous sedimentary construct of ore.