华北石炭、二叠系高分辨层序地层分析

HIGH RESOLUTION SEQUENCE STRATIGRAPHY ANALYSIS ON M PERMO-CARBONIFEROUS IN NORTH CHINA PLATFORM

通过以露头、测井曲线和岩芯观察为基础的高分辨层序地层分析，认为华北石炭、二叠系为1个大层序，时限约为310～250Ma。以早二叠世紫松期与隆林期之交的285Ma的区域性不整合面为界，分为Ms1、Ms2两个中层序。Ms1穿过了石炭、二叠系的年代地层界线（295Ma）。含煤的本溪、太原、山西组（308～275Ma）分为6个层序组（Ss1－6），包括19个层序（CSq17，PSq1-12）。通过区域性层序地层单位的对比，在生物年代地层格架的基础上，建立了更精细的等时地层格架。晚石炭世沉积仅分布在华北中部及北部，南华北缺失CSq1-7，豫西还缺失PSq1-3。层序之间的不整合面、岩石地层单位和主要煤层在大区域内都是穿时的。晚石炭世海水自东向西侵入华北北部，向西和向南超覆；紫松或海水自晋西南和苏皖北部向北入侵，为华北晚古生代的最大海侵；隆林晚期海侵较隆林早期海侵略大。太原组的主煤层在山西自南向北形成于紫松早期海平面缓慢上升过程中，内蒙古南部山西组的巨厚煤层形成于最大海侵时期，山西省山西组的主煤层自北向南形成于隆林早期，晋东南至南华北山西组的主煤层形成于栖霞早期。通过三交、柳林矿区煤相分析表明海侵体系域底部的煤层比高位体系域的煤层更富生烃潜力，是一种新的成煤模式。

Through the high roolution sequence stratigraphy analysis on the Permo-Carboniferous in the North China Platform, it is recognized that the Permo-Caboiferous is a megasequence (310-250 Ma). It can be divided into 2 mesosequences,The sequence beundary wouldbetter be put on 285 Ma, but the chronostratigraphic boundny of Permian and Carforiferous is295 Ma. The coal-bearing strata of Benxi, Taiyuan and Shanxi Formations (the lower 130150 m of them) can be divided into 6 sequence sets(Ss1-Ss6), including 19 sequences(CSq1-7and Pfu1-12). Through the Sequence correlation between the measured and drilling sections, 8cross sections are compiled and the detailed chronostratigraphic depositional frameworks are setup on the basis of biostratigraphic correlation. Carbeniferous lacks in the southem North China, and the limestones of Early Permian overlain directly on the Lower Paleozoic cathenates.The transgression of Late Carbeniferous took place from the east to the west in North China,and extended to the central portion, but the maximurn transgression in Asselian was from thesouthwest and southeast of the platform to the north. The last transgression in Late Sakrnarianwas larger than that in Early Sakrnarian. The main coalbed of Taiyuan Formation in ShanxiProvince, was developed along with the sea level raising and transgression occurring in the beginning of Asselian. The huge thick coalbed of Shanxi Formation, distributed in anthern InnerMongolia and northern Shanxi Province, was formed during the maximtnn transgression of Asselian. The thick coal searns of Shanxi Formation in Shanxi Province, were developed in EarlySakmarian. The thick coal searn of Shanxi Formation in southern North China was developed inLate Sakmrian. The study of coal facies analysis on the coalbed occurring in Saniao and Li-ulin districts indicates that the coals, developed on the botom of the transgressve system tract,usually possess higher hyded potential than that of the coals developed in the highstandsystem tract. Coals developed in TST may be a new coal deopitional modl and are the targetsfor coalbed methane exploration and prediction.