镁质碳酸盐岩建造区域变质及其非金属矿成矿系列

REGIONAL METAMORPHISM OF MAGNESIAN CARBONATE FORMATION OF CHINA AND ITS NONMETALLIC MINEROGENIC SERIES

根据岩石组合和矿床组合的不同，我国镁质碳酸盐岩含矿建造可细分出四个亚建造。其中分别以七种组合形式，产出１２种由区域变质成矿作用形成的非金属矿床，构成一个共生、伴生规律明显、重现性强、经济意义大的成矿系列。

Studies show that this mineromerenic series has seven major characteristics:(1) the ore-bearing formation is cIosely related to the Precambrian magne-sian carbonate rock and might be further divided into four subformations according to the differences in rock association and nonmetallic deposit association;(2 )the minerogenic series includes twelve sorts of mineral deposits,such as dolomite,magnesite,talc,fibrous sepiolite,brucite,diopside,tremolite,serpentine, cblorite,phlogopite and ascharite,and due to the diffe-rence in the ore-forming microenvironment,the minerogenic series finds expression in seven types of mineral deposit associations;(3)the degree of metamorphism of the ore-bearing formation is assigned to greenschist facies and amphibolite facies,to which the minerogenic series is confined;(4)the minerogenic epocb shows polyphase and multi-stage character;(5)the ore-forming materials are cbaracterized by multiple sources,with the magne-sian carbonate rock being the most important source ; repeated hydrothermal activities were super imposed upon the ore deposits formed by regional meta-morphism;as shown by stable isotope studies,the hydrothermal solutions might be metamorphic,magmatic and groundwater hydrothermal solutions or their mixed solutions;(6)regional metamorphism and hydrothermal replace-ment constitute the main ore-forming processes,and the dynamic force that caused regional metamorphism resulted from the convergence and subduction of plates;(7 )the minerogenic series is distributed in the metamorphic terranes near the suture such as eastern Liaoning,eastern Shandong,Qilian-Qinling Mountains and northern Guangxi.Finally,the evolution of the ore-forming process is discussed.