GENETIC MODELS OF THE KAOLIN ROCKS IN THE LATE PALAEOZOIC COAL MEASURES IN NORTHERN SHANXI

In the present paper,the stress is laid on the genesis and regional distribution of the kaolin rocks in the coal measures in northern Shanxi.According to petrographic,miner-alogical and geochemical characteristics,the main enrichment horizons of the kaolin rocks are identified in the Late Palaeozoic coal measures in the study area.They are(1)bauxitic kaolin rocks in the basal part of the Benxi Formation,(2)tonstein in the Taiyuan Forma-tion,and(3)tonstein in the Shanxi Formation.The source rocks of the kaolin rocks may consist of the weathering products or the volcanoclastic sediments.Finally,two genetic models for normally deposited kaolin rocks and for the diagenetic changes of the volcan-oclastic sediments are thus proposed.