湘赣中南部地区煤的岩浆热变质作用

MAGMATIC THERMAMETAMORPHISM OF COAL IN CENTRAL-SOUTHERN HUNAN AND JIANGXI PROVINCE

湘赣中南部地区的煤主要是高变质煤。虽然深成变质作用存在,但煤本身变化显著,煤与石墨、天然焦同层异矿,煤层围岩蚀变和煤变质带展布与侵入岩体及火山岩的分布密切相关等,都证明岩浆热变质作用是湘赣中南部地区煤变质作用的主要类型。印支—燕山期的岩浆活动形成广阔的高温区,从而形成这一地区大量的高变质烟煤和无烟煤。侵入岩体周围形成煤变质正向环带,岩体群之间则形成反向环带;接触带煤变质呈现向石墨或天然焦两个不同的演化方向;叠加在深成变质作用基础上的岩浆热变质作用控制了这一地区煤变质带展布的格局。

The higher-rank coal is predominant in central-southern Hunan and Jiangxi Province. Deep burial metamorphism exists, but magmatic thermametamorphism is the most important coal metamorphism type in this region. Direct evidences are variation of microstructure, physical and chemical properties of coal itself. alteration of country rock of coal seam and different ores including coal graphite and natural coke within the same layer. A vast area of high temperature is formed by magmatic activity during Indo-Chinese-Yanshanian epoch and so much amount of high rank bituminous coal and anthracite are produced here. Coal metamorphism of contact belt presents two different evolution direction which are either to graphite or to natural coke from coal. Intrusive bodies including concealed bodies control the distribution pattern of coal metamorphic zones.