华北盆地南部早二叠世早期聚煤作用的成因机制

华北盆地南部早二叠世早期形成的海陆交替相含煤地层，含有多达30余层煤。这些为数众多的煤层在其形成过程中，受到海水进退和风暴潮2种动力作用的控制。频繁的海水进退，虽然多次为本区的聚煤场所提供了广阔的空间，但未能给滨海沼泽内泥炭物质的持续堆积带来足够的时间。频繁的风暴潮作用对策煤场所既有破坏性又有建设性：风暴上升流可以强烈地侵蚀滨海沼泽的泥炭层，风暴下降流又可将大量的泥炭物质携带到浅海环境再沉积；风暴上升流可以在平缓开阔的潮汐地带上建造成平行海岸线的沙脊，使沙脊靠陆一侧成为新的聚煤场所，下一次较大的风暴上升流又可荡平这些新建立起来的聚煤场所。因此本区的聚煤作用既复杂又特殊。

GENETIC MECHANISM OF EARLY PERMIAN COAL ACCUMULATION IN THE SOUTHERN NORTH CHINA BASIN

The early transitional coal-bearing strata of Early Permian contains more than 30coal-beds. The formation of these coal-beds was strictly controlled by eustatic movement andstorm surges. During the frequent transgressive and regressive periods, a large realm ofnearshore plain is formd. Such a plain rnay provide sufficient space for the coal accurnulation,but there often can not maintain enough time for the continuous accumulation of swamp rnaterials. Frequent storm surge may affect the coal accumulation destructively or constructively. Forexarnple, the storm swashes may scour strongly the coal-beds in nearshore swamp, and the seaward flows may Carry a large amount of swarnp rnaterials to redeposit in neritic environrnnts.Onshore dunes rnay be formed in gentle tidal sone by storm swash, new coal accurnulating spotsrnay occur in the side toward land; but these spots may be destroyed by the next coming largerstorm swash. So the coal accurnulating process is very comlicated and special because of thefrequent changes of sea level and storm surge.