红阳煤田石炭-二叠纪含煤地层的沉积特征

红阳煤田含煤地层太原组与山西组,是一套典型的“海陆交互相”沉积。依据剖面上沉积相序列变化特点,可划分为14个沉积旋回,每个沉积旋回均含有一层煤。有二种聚煤环境:一是海水退出潮坪后形成的泥炭沼泽聚积的煤层;二是扇三角洲平原形成的泥炭沼泽聚积的煤层。

THE SEDIMENTARY FEATURES OF THE CARBONIFEROUS-PERMIAN COAL-BEARING STRATA IN HONGYANG COAL FIELD

The Carboniferous-Permian Taiyuan Formation and Shanxi Formation are the main coal-bearing strata in Hongyang coal field. Their lithological characters and lithofacies are rather stable, and their keybeds are obvious. The most part, about 94%, of these coal-bearing beds are consisted of medium to fine detritus, teeming of biological fossils and their fragments, mainly Brachiopods, Corals, Fusulinids; Lepidodendron, Spenopnyllum, etc. These coal series formed interbededly with marine and terrestrial beds occuring in the littoral plain and characterized of subtidal,tidal-flat,decp lake, lake shore, swampy, peat bog and branching channel facies. According to the serial variation of the sedimentary facies shown in the sections of Taiyuan and Shanxi Formations, six types of cyclothems are recognized, and each formation may be divided into seven cycles. Taiyuan Formation is predominated in cyclothems formed in tidal flat-subtidal facies, while Shanxi Formation predominated in cyclothems formed in lake shore-deep lake facies. All the cyclothems arc unsymmetrical and unrepeated. Coal seams were accumulated in two different environments, one, in peat bogs developed on the tidal flat a regression; the other, in peat bogs developed from lakes in the deltas.