河南省中生代含煤地层中的洪水流沉积

THE FLOOD DEPOSITS IN THE MESOZOIC COAL-BEARING STRATA IN HENAN

摘要:

河南省中生代含煤地层主要包括上三叠统、下中侏罗统、上侏罗统三个层段。由于这些煤系地层多形成在半潮湿、半干旱的气候条件下,洪水流沉积特别发育,尤其是在河南省境内分布最广的上三叠统和上侏罗统地层中。周期性的洪水流沉积在沼泽和泥炭沼泽中反复出现,造成泥炭堆积时断时续,致使上三叠统及上侏罗统地层中的煤层层数甚多,但单层厚度薄,大多为不可采煤层的主要原因。可以认为洪水流沉积是聚煤作用最重要的破坏因素。

Abstract:

Despite their widespread occurrence in the geologic record, the flood deposits have received little attention of the majority of geologists. The authors propose, on the basis of the detailed investigation, that large amounts of the flood deposits occur in the Mesozoic strata in Henan in a variety of geological environments such as flood plain, lakeshore and shallow to deep lake, flood basin in the alluvial plain envionments of meadering rivers and the frontal zone of the alluvial fan where the braided streams are well-developed. Morever, the flood deposits in different environments are of quite variable in character. The present paper deals in detail with sedimentary characteristics and conditions for the formation of the flood deposits in the study area.