太原东山晚古生代含煤岩系沉积环境与古河道地貌和水文参数

SEDIMENTARY ENVIRONMENTS,PALAEOCHANNEL MORPHOLOGY AND HYDROLOGIC PARAMETERS OF THE LATE PALAEOZOIC COAL-BEARING STRATA IN THE EAST HILL AREA,TAIYUAN,SHANXI

摘要:

太原东山-寿阳勘探区位于沁水盆地西北隅。煤系沉积环境演化规律是:本溪组主要是受潮汐作用影响的泻湖和海湾沉积环境,太原组和山西组下部是三角洲沉积环境,向上过渡为上三角洲平原—冲积平原沉积环境。依据地层三分法原则,提出了东山与西山岩石地层对比,并阐述“东山砂岩”命名的必要性。定量地质学可以作为研究古代沉积环境的辅助方法。

Abstract:

The correlation between lithostratigraphy and marker beds of the East Hill and West Hills, Taiyuan,Shanxi has been proposed by the authors according to the tripartite method. The formerly named "Luotuobozi Sandstones" now has been renamed as the "East Hill Sandstones" （K₈）.
The regressive palaeogeographic evolution has been recorded in the coal-bearing strata over 200 m thick. The Benxi Formation composed dominantly of black shales, lenticular limestones and thin coal beds with higher sulfur contents is interpreted as the littoral lacustrine sediments and tidally influenced lagoonal and bay sediments. From the Jinci Sandstones （K₁） upwards, there are gradations from lagoon and bay to fluvial-dominated shallow-water deltaic environments. In the Taiyuan Formation and the lower part of the Shanxi Formation, there are five deltaic cycles, each of which, about 20-30 m in thickness, was deposited in the order from bottom to top: limestones, black shales, siltstones, tabular cross-bedded sandstones, rhizoliths and coal seams,whereas in the Shanxi Formation, only abundant plant remains have been recognized. The channel sandstone facies are found to be interspersed with the lacustrine and flood-basin facies.
The estimates of hydrologic parameters such as flow velocity and flow amount of river water and the analysis of palaeogeomorphology were also made by the authors on the basis of the current theory on sedimentology and the data from measured sections. They may be well-concurred with the geological information. It is concluded that the quantitative geological analysis will be a stimulation to the study of sedimentary facies and palaeogeography.