菏泽地区含煤地层基准面旋回与成煤作用研究

Study on Base Level Cycle and Coal Formation in Coalbearing Strata in Heze Area

摘要:

采用了地层学、沉积学、煤地质学等多学科相结合的方法，对菏泽地区晚古生代石炭—二叠系的高分辨率层序地层进行了基准面旋回划分，通过分析该地区基准面旋回变化特征，探讨了其与成煤作用的耦合机制。研究发现：菏泽地区石炭—二叠系沉积可以划分为2个超长期、5个长期、12个中期和30多个短期基准面旋回。通过对比整个菏泽含煤区高分辨率层序地层，总结出基准面旋回与成煤作用关系，发现LSC1中的17煤层、18煤层主要形成于障壁海岸环境之中，主要发育于基准面由快速上升转变为缓慢下降，为典型的水退成煤。LSC2中的16煤层是形成于潮坪环境之中，发育于基准面快速上升时期，为海侵事件成煤。LSC3旋回中的3煤层形成于陆表海浅水三角洲环境之中，发育于基准面由海平面快速上升到减缓上升然后转为缓慢下降，为典型的三角洲海退成煤。

Abstract:

By using multidisciplinary combination of stratigraphy, sedimentology and coal geology, base level cycle division has been carried out in late Paleozoic CarboniferousPermian high resolution sequence stratigraphy in Heze area. Through analysis on variation characteristics of base level cycle, the coupling mechanism with the effects of the coal has been studied. It is found that the sedimentary deposits in Heze area can be divided into 2 super long period, 5 long period, 12 medium period and 30 short period base level cycles. Comparing high resolution sequence stratigraphy in coalbearing areas in Heze city, the function relationship between base level cycle and coal has been summarized. It is found that No.17 and No.18 coal layer in the LSC1 cycle were mainly formed in the barrier coast environment in rapidly rising period to slow down period. The coal would be formed after the water retreated. No.16 coal layer in LSC2 cycle was formed in the tidal flat environment in rapid rising period. The coal was formed by transgression events. No.3 coal layer in LSC3 cycle was formed in the shallow water delta environment in the epicontinental sea in rapid rising sea period to slowing up and then to slowing down period. The coal was formed by typical delta regression.