西藏类乌齐马查拉煤矿沉积环境与聚煤规律初探

Brief study on the sedimentary environment and coal-accumulation pattern of Machala Coalfield in Leiwuqi County of Tibet

西藏昌都马查拉煤矿是整个西藏范围内马查拉煤系最典型煤矿。本文通过对马查拉煤矿内沉积剖面的系统研究和对比,主要从剖面结构、基本层序、沉积构造及其古生物化石组合等特点分析,认为马查拉煤矿形成的沉积环境是在浅海环境基础上发育的海陆过渡环境;在较系统分析马查拉煤矿晚三叠世构造-岩相古地理格局基础上,认为马查拉煤矿形成时聚煤盆地属于大陆边缘坳陷型聚煤盆地,聚煤沉积相为陆源碎屑潮上带之泥炭沼泽相;含煤地层在空间分布上表现出由NW向SE厚度逐渐变薄的特点。

The Changdu Machala coal is the most typical Machala coal-series coal in the scope of the whole Ti- bet. In this paper, through study and contrast the sedimentary section systemic of the Machala coal mine, mainly from analysis the cross-sectional structure, sequence, sedimentary structures and the characteristics of fossils combination has got that the formation sedimentary environment Machala coal is the neritic environment that de- velopment based on transitional environment. Through systematic analysis of the Late Triassic structure-lithofa- cies palaeogeographic of the Machala coal, we proposed that the formation coal-basin of Machala coal is the con- tinental margin depression coal basin, sedimentary facies is the terrigenous clastic supratidal peat swamp facies. The coal-bearing strata shows the characteristics that gradual thinning from northest to southest.