内蒙古扎兰屯地区龙江组孢粉组合及其地质意义

成吉思汗驿站龙江组剖面位于扎兰屯成吉思汗镇东南部,组内大化石稀少,但孢粉化石丰富,下部岩性为沉凝灰岩、凝灰岩、凝灰质砂岩、砂岩、砾岩,上部岩性为安山岩、英安岩。通过对成吉思汗驿站龙江组孢粉化石的分析,在龙江组中识别出圆形粒面孢-二连粉孢粉组合带(Cyclogranisporites-Erlianpollis)。通过对孢粉化石属种的分析,根据具有时代指示意义的孢粉化石,如Erlianpollis,Cicatricosisporites,Pilosisporites等,认为成吉思汗地区龙江组孢粉化石形成时代为早白垩世,结合地质、古植物及孢粉化石的定量分析,认为龙江组植被类型反映亚热带气候,指示温暖潮湿的环境。

The palynological assemblage of the Longjiang Forma-tion in Zhalantun area, Inner Mongolia, and its geological implications

Located in the southeastern Chenjisihan Town of Zhalantun area, the Longjiang Formation in the ChenjisihanYizhan con-tains abundant palynological fossils but rare macrofossils. The lithological assemblages of the lower Longjiang Formation are composed mainly of sedimentary tuff, tuff, sandstone and conglomerate, while those of the upper Longjiang Formation comprise predominantly andesite and dacite. By analyzing the palynological fossils from the Longjiang Formation in the ChengjisihanYizhan area, the Cyclogranisporites-Erlianpollis pollen assemblage zone was recognized. Several palynological fossils, such as Erlianpollis, Cicatricosisporites and Pilosisporites, indicate that the palynological fossils of the Longjiang Formation of Chengjisihan area formed in Early Cretaceous. In combination with geological characteristics and quantitative analysis of plant fossils and palynological fossils, vegetation species of the Longjiang Formation point to a subtropical climate and a warm and humid environment.