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地质勘查揭露,在冀西北康保地区忠义凹陷内赋存有一套半固结杂色含煤碎屑岩沉积,厚度400~800余米,分布面积达500 km2。之前认为该地层为上侏罗统后城组、中侏罗统下花园组上段和古近系始新-渐新统灵山组,本次工作采集了孢粉样品,经分析获得了比较丰富的孢粉化石,化石组合的显著特点是含有丰富海金沙科孢子,其中Cicatricosisporites百分比含量丰富且分异度高,没有被子植物花粉的踪迹,时代应为早白垩世中期,层位与冀北西瓜园组和辽西九佛堂组相当。依岩性、孢粉组合,建议该套地层称为九佛堂组。该地层的发现不仅对建立本区比较完整的地层层序和标准地层格架有益,而且对于深入研究燕山地区侏罗-白垩纪的大地构造演化过程和燕山运动的构造期次划分具有重要意义。
Geological exploration revealed that there is a set of semi-solidified mottled coal-bearing clastic sediments within the Zhongyi Sag in the northwest Hebei Kangbao area, with a thickness of 400 to 800 meters and a distribution area of 500 km2. Previously, it was considered that the strata were Upper Jurassic Houcheng Formation, Upper Jurassic Lower Garden Formation and Paleogene Eocene-Oligocene Lingshan Formation. Pollen samples were collected from this work, and relatively abundant Sporopollen fossils, fossil assemblage is notable for its rich spores of the genus Houttuynia, in which Cicatricosisporites is rich in percentage and highly differentiated and has no traces of pollen of angiosperms. The age should be in the mid-early Cretaceous, The group and the western Jiufo Church group quite. According to lithology, sporopollen assemblage, it is suggested that this formation is called Jiufotang Formation. The discovery of this stratum is not only beneficial to the establishment of a relatively complete stratigraphic sequence and standard stratigraphic framework in this area, but also important for the further study of the tectonic evolution of the Jurassic-Cretaceous and the structural division of the Yanshanian movement in the Yanshan area.