鸡西盆地高分辨率层序地层研究与聚煤作用分析

High-Resolution Sequence Stratigraphy Features and Mechanism of the Coal Formation in the Chengzihe Formation of Jixi Basin in Eastern Heilongjiang Province

采用露头、钻井、钻孔剖面资料对鸡西盆地北部含煤条带中城子河组进行了高分辨率层序地层划分和对比,共识别出2个长期、7个中期、44个短期基准面旋回。中—长期基准面旋回由上升、下降两个半旋回构成对称型结构,在不同剖面中对应标志明显;短期基准面旋回分为对称型和非对称型两种,自盆地中部至盆地边缘基准面旋回个数递减。通过对各级别基准面旋回的分析,讨论了高分辨率层序与聚煤作用关系。长期基准面旋回总体上制约了煤层的分布规律,完全对称型旋回和不完全对称型上升半旋回聚煤作用总体偏好,是找煤远景层位;中—短期基准面下降半旋回聚煤作用较好,是重要工业煤层的有利赋存部位。研究结果显示城子河组第①、②、④、⑥个中期基准面旋回聚煤作用最好,是采煤及扩大远景找矿的首选层位。

Based the data of the exposures and the drilling, through the high-resolution sequence stratigraphy subdivision and correlation, two long-term, seven middle-term, forty-four short-term base-level cycle sequences are distinguished in the Chengzihe Formation of striped-coaling in the north of Jixi basin. The middle-term to the long-term base-level cycle sequences appear to symmetry structures being made of the two half-cycle of rising and falling. And there are obviously corresponding marks in the different profiles. The short-term base-level cycle sequences are divided into two basic types of symmetry and non-symmetry, and the numbers of base-level cycles decreased progressively from the middle of the basin to the edge. By the analyses of the various base-level cycle sequences, the relation between the high-resolution sequences and the mechanism coal formation is discussed. The long-term base-level cycle sequences restricted the distribution of the coal beds entirely. The coal formation in the entire symmetry cycle and the rising half-cycle in the non-entire symmetry cycle is generally good, which is the long-range prospecting coal layer. And the coal formation in the middle-short base-level with falling half-cycle is better, which is the good place for the important industry coal beds. The study shows the mechanism of the coal formation in the middle base-level cycle of the ①、②、④、⑥ is the best one. These are the preferential beds of coal cutting and prospecting.