法国、中国断陷盆地厚煤层堆积机制分析

ANALYSIS ON ACCUMULATION MECHANISM AND SEDIMENTARY CONDITIONS OF THICK COALBEDS IN SINO-FRENCH FAULTED COAL BASINS

从法国中央地块晚石炭世的3个内陆山间小型断陷聚煤盆地厚煤层的成因标志和沉积特征出发，讨论了这些煤层独特的堆积机制及其沉积-构造条件，并与中国东北早第三纪抚顺盆地超厚煤层的沉积条件做了比较分析，指出了2个大陆间在厚煤层的堆积背景与条件方面的差异性和共同点。尤其是这些盆地均发育于活动的构造背景之下，盆缘、盆内断层活动强烈，且控制着沉积相带的展布及富煤单元的时空分布；煤层内均发育有大量的重力流沉积物——碎屑流。稀性泥石流或浊流沉积物；煤层自身存在同沉积期的重力滑塌。变形构造和大量的再搬运-再堆积的记录，表明厚（巨厚、超厚）煤层在堆积时的湖泊环境为覆水较深、不稳定的沉积环境，并且煤（泥炭）在初次堆积后经过了再次搬运而成为异地堆积的产物。这为提出厚煤层新的堆积机制，即异地堆积提供了重要而可靠的证据和实例。

Based on the analysis of abundant genetic and sedimentary indicators of the thick(ultra-thick) coalbeds in three ed-fodng faulted basins on the Massif-Central of France, theauthors discuss the distinct accurnulation pattem of thick coalbeds and their tectono-sedimentaryconditions. Comparing with the fodring condition of thick anlbeds in Eocne Fushun coalbasin in East China, a new formation mechanism for the continental (intramontaneous) thick(ultrathick) lacustrine allochthonous coal (peat) accurnulation medel is demonstrated. In thisnew mechanism, the subaquatic gravitational current tranported the organic (peat) and inorganic clasts formed in lakeshore swamp int0 the central lake wherein these anl (peat) wereformed in an active clastic envimnt, and were siiated with various gravity-influencedmudstone and sandstone interlayers. The new allochthonous acctimulation model can provide areasonable interpretation to the genesis of the continental (intramntaneous) thick (ultra-thick)edbeds and can open a new approah to the study of the other genetical thick (ultra-thick)coalbeds.