摘要
侵入岩中的金矿床多为改造作用形成。赋矿侵入体岩性多样，从超镁铁─镁铁到中性─酸性─碱性成分均有发现。岩体发育在克拉通、克拉通边缘活化带及褶皱带中，其时代从太古宙到燕山期都有发现。其中超镁铁岩─镁铁岩─闪长岩─碱性岩─斜长岩为上地幔或土地幔─下地壳的重熔或混染的产物，中─酸性岩为地壳深部含金火山沉积岩系重熔形成。金矿床有细脉浸染、石英脉、细脉浸染＋石英脉等类型。在大岩体中矿床发育在内接触带的断裂系中，而在小岩体内则遍及岩体及其内外接触带。成矿时代主要为燕山期，其次为海西期、太古宙，较少为喜马拉雅期及元古宙，成矿与成岩之间有大的时差存在。成矿物质来自岩体及含金岩系，成矿流体以大气降水及建造水为主。矿床为地质晚期深部热流沿断裂上升加热了浅部的循环水，并从侵入岩及含金岩系中淋出了金再迁移到上部沉积出而形成。
Most of gold deposits in intrusive rocks resulted from the reworking process. The composition of ore-hosted rocks vades from ultramafic-mafic, intermediate-acid,to acidic rock. The intrusive rocks occurring in craton, acdvated zone of craton and fold zone were formed from Archean to Yanshanian pedals. It is considered dut the series of ultramafic-mafic rock, diorite, alkaline rock and anorthosite resulted fromthe anatexis or hybntdizadon of upper mande , or upper mantle-lower crust, and theacidic rock resulted from the remolding of gold-rich formadon in the lower part of the crust. The ores in the intrusive roclu consist of venial-disseminated, quartz vein and veinlet-disseminated+quartz vein. The ore bodies hosted by bigger iatnuive masses are developed along fault zones in endocontact, and those hosted by smaller intrusive masses are in the whole rock as well as in the contact zone There is a great dme gap between the formation of gold deposits and of rocks. The main formation times of gold deposits were Yanshanian period, and then Hercynian and Archean, only a few of them were formed in the Caledonian and Proterozoic times. It is considered that the ore-forming materials came from the intensive rock and gold-rich formation:and the ore-forming fluids were mainly meteoric water and formation water. The ore-forming process could be concluded as following: in the late geological event gold was leached from the intrusive rock and gold-rich formation by circulating water heated by heat cumant which came along the fault from the lower part and then ascended to the upper part and eventually the gold was precipitated due to the changing of geochemical condition.
出处
《地球化学》
CAS
CSCD
北大核心
1997年第4期1-12,共12页
Geochimica
基金
国家自然科学基金
关键词
侵入岩
金矿床
物质来源
改造成矿
成矿机制
intrusive rock, gold deposit. time gap between rock and ores, ore-forming source material, reworking genesis
