河北南部地区石炭—二叠纪层序地层与聚煤特征

Permo-Carboniferous Sequence Stratigraphy and Coal Accumulation Features in Southern Hebei

根据大量野外剖面及钻孔资料,将河北南部地区晚石炭世至早二叠世地层划分为4个含煤层序。层序1为第一个关键成煤层序,代表了海陆交替型含煤岩系形成期间的第一次大规模海水进退序列,含有全区可追踪对比的煤层,但聚煤作用较弱;层序2为第二个关键成煤层序,由于盆地的构造转换引起海侵方向的改变,该层序煤层为海侵事件成煤,形成了全区稳定发育的大青煤(8#);层序3为华北板块发生"翘翘板"运动后的稳定沉积层序,高水位体系域形成的煤层稳定性好(6#、7#);层序4为陆表海盆地向陆相盆地过渡形成的含煤层序,该层序高位体系域含煤性好,煤层厚,全区可对比。

Based on large amount field sections and borehole data, divided Late Carboniferous to Early Permian strata in the southern Hebei into four coal-bearing sequences. Sequence Ⅰ is the key coal-forming sequence, represents the first extensive marine progression and regression sequence during continental-oceanic alternating type coal-bearing rock series formation, contains coal seams can be traced and correlated in whole area, but rather weak coal accumulation process. Sequence Ⅱ is the second key coalforming sequence, due to structural transformation caused the changeover of marine transgression direction, coal seams in the sequence belong to transgression coal-forming and formed the Daqing coal seam （No.8 coal） stably well developed in the whole area. Sequence Ⅲ is a stable sedimentary sequence was formed right after the ＂seesaw＂ action of the North China Plate, coal seams （No.6 and No.7 coals） formed in the highstand systems tracts （HST） have good stability. Sequence Ⅳ is a coal-beating sequence was formed during the transition of epicontinental sea basin to limnic basin, coal-bearing property in this HST is good with thick coal seams and can be correlated in the whole area.