山东及邻区石炭二叠纪含煤地层的层序地层式样

The Sequence Stratigraphical Pattern of the Permo-carboniferous Coal Measure in Shandong and Its Adjacent Area

山东及邻区石炭二叠纪海陆交替型含煤地层为内陆表海盆地沉积，可划分出三个Ⅲ级层序，其分界面为Ⅲ级海平面变化的周期性界面，在华北广大地区表现为整合面。含煤层序的基本结构特点为＂二元型＂，即＂海侵－高位＂的体系域叠置型式。海侵体系域由１－２个小层序构成，高位体系域为４－７个小层序构成。因此，华北内陆表海含煤盆地层序格架与北美大陆边缘海含油气盆地的层序模式具有根本上的差异。

Sequence stratigraphical analysis in epicontinental paralic coal measure is a new problem for study. Based on the sedimentary characteristics of Permo-carboniferous coal measure in Shandong and its adjacent area and the general feature of the vast coal-bearing depositional basin of North China,using the thought,method and techique of sequence stratigraphy originated from the study of marine basin, the authors have carried out the sequence stratigraphical analysis in paralic coal measure. Our research shows that the Late Paleozoic paralic coal measure in the study area can be divided into three third order sequences which are seperated by periodic surface of third order sea-level changes. The three boundaries of sequence are comformity planes in North China area. The basic architecture of the coal bearing sequences are characterized by dualistic pattern, which differs from the typical u lowstand-trausgressive-highstand 'model established by North American scholars in the study of continental marginal oil-gas basin.The classfication of sequences, the identification and the follow-up correlation of various order surfaces of internal units in sequence have solved the confused correlation problem in the study of vertical succession.The correlating analysis of depositional systems, and system tracts, and the determination of the stratigraphical frame of coal bearing sequence provide the bases for the basin-filling analysis of the vast epicontinental basin. In this paper, the classification of parasequences and the characteristics of their boundaries are discussed. Research also shows that the transgressive systems tracts consist of I to 2 parasequences, and the highstand systems tracts are composed of 4 to 7 parasequences. Seventeen parasequences are distinguished in the three third-order sequences, most of them are of periodic parasequences. The classification of parasequences is dependent on the identification of regional transgressive boundaries. In the paralic coal measure developed in the epicontinental sea, the thin-layered stable transgressive beds,the extensively distributed tidal flat deopsits and peat swawp deposits provide correlation basis for the classification of parasequences.