开鲁盆地东北部钱家店凹陷晚白垩世姚家组孢粉组合及其古气候意义

发布时间：2018-05-19 09:52

本文选题：孢粉组合 + 古气候　；参考：《地球科学》2017年10期

【摘要】：对于开鲁盆地姚家组孢粉学的研究不仅丰富了该地区晚白垩世孢粉学资料,而且为该地区晚白垩世地层划分与对比提供了依据.通过对开鲁盆地钱家店凹陷钻孔QIV-48-61深315~447m井段的岩心做了详细采样、描述,并进行了孢粉化石的处理、鉴定和分析,在其中的10个层位中发现了丰富的孢粉化石,共计73属88种,并建立了3个孢粉组合,自下而上依次为Schizaeoisporites-Cyathidites-Tricolpopollenites,Schizaeoisporites-Classopollis-Taxodiaceaepollenites和SchizaeoisporitesExesipollenties-Tricolpopollenites,根据孢粉组合内一些重要分子的地质时限及与外区有关孢粉组合的对比,将其时代划归为晚白垩世Coniacian晚期-Santonian早期,其层位相当于姚家组.根据孢粉母体植物形态和生态特征、干湿度环境和气候环境,将其孢粉植物群反映的植被、干湿度和气候带划分为3个演化阶段:第1演化阶段(405.9~413.2m)沉积时期植被面貌大体为针叶林与草本共生,对应于湿润、半湿润的热带-亚热带气候;第2演化阶段(389.7~405.9m)植被面貌演化为以高大乔木型针叶树种占优势地位,并出现一次明显的干旱化事件,对应于半干旱的热带-亚热带气候;第3演化阶段(336.0~389.7m)植被面貌与第1阶段相似,为针叶林与草本共生,干旱化有所缓解,对应于半湿润-半干旱的热带-亚热带气候.
[Abstract]:The palynological study of the Yaojia formation in the Kailu Basin not only enriches the palynological data of the late Cretaceous, but also provides the basis for the stratigraphic division and correlation of the late Cretaceous in this area. Based on the detailed sampling and description of the core of the borehole QIV-48-61 (315 ~ 447 m deep) in Qianjiadian sag, Kailu Basin, and the treatment, identification and analysis of sporopollen fossils, abundant sporopollen fossils were found in 10 of them, with a total of 73 genera and 88 species. Three sporopollen assemblages, Schizaeoisporites-Cyathidites-Schizaeoisporites-Classopollis-Taxodiaceaepollenites and SchizaeoisporitesExesipollenties-Tricolpopollenites-Schizaeoisporites-Cyathidites-Cyathidites-Schizaeoisporites-Taxodiaceaepollenites and Schizaeoisporites-Exesipollenties-Tricolpopollenites were established. According to the geological time of some important molecules in the sporopollen assemblage and the correlation of the pollen assemblages with the outer area, the age of the assemblage was classified as the early Santonian of late Cretaceous Coniacian. Its horizon is equivalent to the Yao formation. According to the morphology and ecological characteristics of sporopollen parent plants, the dry and wet degree environment and climate environment, the vegetation reflected by its sporopollen flora was studied. The dry-wet degree and climatic zone can be divided into three stages: in the first stage, the vegetation features of coniferous forest and herbaceous symbiosis, corresponding to the humid, semi-humid tropical and subtropical climate; In the second stage of evolution, the vegetation features evolved to be dominated by tall coniferous tree species, and an obvious drought event occurred, corresponding to the semi-arid tropical and subtropical climate. In the third stage of evolution, the vegetation features are similar to that of the first stage. The vegetation is associated with coniferous forests and herbaceous herbs, and drought is alleviated, corresponding to the tropical and subtropical climate of semi-humid and semi-arid.
【作者单位】：中国地质调查局天津地质调查中心;中国地质调查局天津地质调查中心非化石能源矿产实验室;辽河石油勘探局新能源开发公司;
【基金】：国家重点基础研究发展计划(973计划)项目(No.2015CB453000) 中国地质调查局项目(No.DD20160128)
【分类号】：P532;Q914

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