吕梁山东北缘寒武系层序地层划分--以文水苍尔会剖面为例

Sequence stratigraphy division of Cambrian in the northeast area of Luliang mountain:A case study of the Cangerhui section in Wenshui city

为研究山西吕梁山地区寒武纪地层的地层学与沉积学问题,根据山西文水苍尔会剖面寒武系地层叠置关系,将该剖面寒武系地层划分为8个三级层序。基于沉积相的变化规律和地层叠置关系的旋回性研究结果,苍尔会剖面存在两个特殊的地层学与沉积学现象:下部为霍山组砂岩直接覆盖在太古宙变质岩系上,其较为良好的出露与明显的地层接触关系,为探讨山西中部霍山组砂岩的地层归属问题提供依据;在该剖面崮山组、长山组、凤山组中分别发育不同的均一石生物丘,代表华北地台寒武纪晚期—奥陶纪中期"随着后生动物辐射,微生物碳酸盐也在增加"微生物碳酸盐复苏期的基本沉积样式。在新的寒武纪年代地层框架下,对山西文水苍尔会剖面进行层序地层划分,不但为研究华北寒武系生物丘沉积组构多样性提供参考实例,同时也为探讨山西中部地区前寒武—寒武巨大的古地理变迁提供实例。

The Cambrian strata in Cangerhui section can be subdivided into 8 third-order sequences according to the characteristics of sedimentary facies stacking patterns,in order to study the stratigraphy and sedimentology of Cambrian strata widely exposed beside the Luliang mountain in Shanxi province,middle part of North China platform.There are two special sedimentary and stratigraphy phenomena in this section：The red and yellow bedded of Huoshan formation is angle unconformity with Archean metamorphic rocks,the clear outcrop and directly feature on the stratigraphy provide reliable basis in doing the research towards the stratigraphic attribution of Huoshan formation;beyond that,various kinds ofbioherms widely developed in the upper part of Gushan formation,Changshan formation and Fengshan formation which represent the increasing of microbial carbonate abundance with the radiation of metazoan and the basic sedimentary pattern of microbial carbonate recovery period.Based on facies superposition model and stratigraphic record cycle and new chronostratigraphic framework of Cambrian,the current sequence stratigraphic framework of the Cambrian strata in Cangerhui section will provide a reference example for the exploration of the sedimentary fabrics diversity of Cambrian bioherm in North China platform and also clues for the comparative studies and correlation on regional scale about the strata widely distributed in the middle area of Shanxi province.