华北晚古生代煤变质演化及煤质预测

华北晚古生代煤具有中部和南部变质程度较高而南部边缘和北部低的特点。这是华北晚古生代经历了3个阶段变质演化的结果。华北地台稳定阶段除个别地区外,深成变质作用使绝大多数晚古生代煤只演化到低变质阶段;地台活化早期叠加的区域岩浆热变质作用造成部分低煤级媒提高到中、高变质阶段;地台活化晚期紫荆关断裂的右旋移动奠定了华北晚古生代煤变质分布的格局。根据岩浆性质、侵入规模等特点将区域岩浆热变质作用划分为3个亚型。区域岩浆热变质煤的分布受燕山期岩浆沿一定方向断续侵入的控制。从成因上阐述区域岩浆热变质作用的主要特点。基于地质因素分析和煤变质作用类型预测华北晚古生代煤级分布,新的预测增加了炼焦煤的储量,且部分已被钻探证实。

THE METAMORPHIC EVOLUTION OF THE LATE PALEOZOIC COAL AND IT'S RANK PREDICTION IN NORTH CHINA

In North China, the late paleozoic coal was metamorphosed mainly to middle and high ranking in the central and southern belts, but only to low, ranking in the northern belt and southern margin. Such a feature is the comprehensive result of coal metamorphism through three evolutional stages. During the stable stage of the North China platform the late paleozoic coal evolved through geo-thermal metamorphism only to low ranking- except in some individual region, in the early mobile stage of the platform, part the Low rank coal had been promoted to medium end high metamorphic stages by additional telemagmatic metamorphism due to the strong magmatic intrusion of Yanshan Movement, in the late mobile stage the dextrally moving of the Zijingguan fault zone constructed the distribution frame of the late Paleozoic coal metamorphit: xonatioa in North China. Based upon the nature and intruding scale of the intrusives and other characteristics three subtypes of telemagmatic metamorphism are subdivided. Distribution of the telemagmatic metamorphosed coal is controlled by the Yan?shan intrusives which were intruded discontinuously along certain directions. The characteristics and determining indices of coal telemagmatic metamorphism are discussed with respect to their genesis. Taking the geologic analysis and the type of coal metamorphism as bases the rank distribution of late Paleozoic coal in North China is predicted. The predicting reserves of coking coal have been increased in the new assessment and is already partly proved by drilling.