Study on coal lithology and coal quality characteristics and coal forming environment of Yan'an Formation in Ningxia
The Middle Jurassic Yan'an Formation is one of the main coal-bearing strata in Ningxia,mainly distributed in Ningdong Coalfield,Ningnan Coalfield,Rujigou mining area of Helan Mountain Coalfield,Xialiushui and Yaoshan Basin of Xiangshan Coalfield.In order to reveal the characteristics of coal lithology and coal quality and coal-forming environment of Yan'an Formation in Ningxia,based on the geological survey data of coal rock,industrial analysis and total sulfur of coal samples in various recoverable coal seams,the char-acteristics of Jurassic Yan'an Formation coal in Ningxia were analyzed,and the relationship between ash and sulfur content in coal and sedimentary environment of coal formation was discussed.The results show that the Yan'an Formation in Rujigou mining area of Helan Mountain Coalfield is dominated by semi-bright and bright coal,rich vitrinite,ultra-low to low ash,ultra-low sulfur;Ningdong and Ning-nan Coalfields are dominated by semi durain;Ningdong Coalfield is rich in inertinite,medium high to high volatile,ultra-low to low ash,ultra-low to low sulfur;Ningnan Coalfield is rich in vitrinite,high volatile,low ash,low to medium sulfur;Xiangshan Coalfield is rich in vitrinite,low ash,extra low to low sulfur.Generally,the sedimentary environment of Yan'an Formation can be divided into two catego-ries:fluvial system and shallow lake delta system,and its formation has experienced the filling evolution process of alluvial plain,shallow lake delta and then transition to alluvial plain.The results can provide basic geological data and theoretical basis for the study of clean and efficient utilization of Jurassic coal in Ningxia.
Ningdong CoalfieldNingnan CoalfieldYan'an Formationcoal lithology and coal qualitycoal forming environment
万方数据
维普
