冀辽一带的土城子组和大北沟组对中国北方侏罗系–白垩系划分对比具有重要的意义。关于它们的时代目前还存在不同的看法, 相关的孢粉地层学研究也比较粗略。本文研究了冀北滦平县井上村三岔子剖面土城子组和大北沟组的孢粉组合, 共观察统计到50属28种及若干未定种。土城子组Classopollis–Cooksonites–Ephedripites组合以Classopollis含量最为突出, 同时含有白垩纪分子Cooksonites variabilis、Crybelosporites punctatus和Ephedripites (E.), 其时代为早白垩世Berriasian期。大北沟组Bisaccates–Foraminisporis组合以松柏类两气囊花粉占绝对优势, 见有Crybelosporites punctatus、Ephedripites (E.) crassistriatus、Foraminisporis wonthaggiensis、Jiaohepollis和Rugubivesiculites spherisaccatus等具有时代意义的分子, 其时代为早白垩世Valanginian中–晚期。本研究首次报道了土城子组一段顶部的早白垩世孢粉组合, 提出了中国北方侏罗系–白垩系界线位于土城子组一段内的新意见。孢粉组合对比表明当前冀北滦平盆地大北沟组Bisaccates–Foraminisporis组合与辽西金岭寺–羊山盆地土城子组三段顶部及其上覆义县组下部的孢粉组合非常相似。因此, 从孢粉植物群的发育来看, 滦平盆地大北沟组可能与金岭寺–羊山盆地土城子组三段顶部至义县组下部相当。

The Tuchengzi and Dabeigou formations of the Hebei and Liaoning Provinces are of great significance for the Jurassic–Cretaceous stratigraphic division and correlation in northern China. However, the geological age of the two formations is still controversial, and only preliminary researches have been done on the palynostratigraphy. In this paper, moderately diverse pollen and spores are recovered from the Tuchengzi and Dabeigou formations at Sanchazi, Jingshang Village, Luanping County, northern Hebei Province, which comprise 50 genera and 28 species together with some indeterminate species as well. The palynoassemblage of the Tuchengzi Formation, namely Classopollis–Cooksonites–Ephedripites assemblage, is characterized by the predominance of Classopollis and considered to be Berriasian in age (Early Cretaceous) by the occurrence of Cooksonites variabilis、Crybelosporites punctatus and Ephedripites (E.). The Bisaccates–Foraminisporis assemblage recovered from the Dabeigou Formation is dominated by gymnospermous pollen and is evidenced of a middle–late Valanginian age by the occurrence of such age-diagnostic elements as Crybelosporites punctatus, Ephedripites (E.) crassistriatus, Foraminisporis wonthaggiensis, Jiaohepollis and Rugubivesiculites spherisaccatus. The present work uncovers an Early Cretaceous palynoflora from the top of the First Member of the Tuchengzi Formation for the first time, implying that the Jurassic–Cretaceous boundary in northern China lies within the First Member of the Tuchengzi Formation. Our research also shows the Bisaccates–Foraminisporis assemblage of the Dabeigou Formation in the Luanping Basin, northern Hebei Province is correlative to that from the top of the Third Member of the Tuchengzi Formation and the lower part of the Yixian Formation in the Jinlingsi–Yangshan Basin, western Liaoning Province, which means an equivalency of these strata.