摘要
所研究的孢子花粉化石产自鄂尔多斯盆地北部志丹群喇嘛湾组,计有53属、74种。根据孢粉组合特征、主要属种地史分布及与已知孢粉组合对比、分析,指出该组时代为早白垩世早中期。此外,作者对喇嘛湾组孢粉植物群所反映的古气候环境做了初步探讨,推测沉积区在喇嘛湾组沉积时受温暖潮湿气候条件的控制,并将该孢粉植物群归于瓦赫拉梅耶夫(Vakhrameev,1978)划分的西伯利亚—加拿大植物区。
The Ordos basin is situated in the northwestern China, in which meso- soic continental sediments are well developed. The spores and pollen studied in this paper were obtained from the Lamawan Formation of the Zhidan Group in northern Ordos basin, amounting to 53 genera and 74 species. In the spore-pollen assemblage of the Lamawan Formation, pollen grains of Gymnospermae are dominant, amounting to 63.5% in the total mumber, while spores of Pteridophyta occupy second place (36.2%), and fresh water algae are very rare(0.3%). In pteridophytic spores, Lygodiaceae is more rich in composition, including main elements. Lygodiumsporites subsimplex, Concavissimisporites punctatus, C. subgranulosus, C. subverrucosus, Cicatricosisporites australiensis, C. dahuichangensis, C. daxinganlingensis, C. of. minutaestriatus, C. proxiradiatus, C. implexus, C. exilioides, Impardecispora sp. and Pilosisporites parvispinosus, amounting to 12.4%, among them the genus Concavissimisporites counts 6.4％. The genus Cicatricosisporites occupies 4.5％ of the assemblage and reaches 9.9% in individual sample. There are common elements. Laevigatosporites (4.7), Fixisporites (3%), Cyathidites (2.3%), Granulatisporites (2.5%), Osmundacidites (1.1%) and Foraminisporis(2.8%). Besides, Stereisporites, Deltoidospora, Hymenophyllidites, Cibotiumspora, Undulatisporites, Biretisporites, Todisporites, Densoisporites, Hsuisporites of. multiradiatus, Converrucosisporites, Verrucosisporites, Klukisporites, Contignisporites cooksonii, C. dongbeiensis, Aequitriradites verrucosus, Interulobites triangularis, Bayanhuaspora setacea and Triporoletes reticulatus are few, all of them are not more than 1% in the assemblage. In gymnospermous pollen bisaccate pollen is the highest content(35.7%) and present following genera: Protoconiferus (5.4%), Protopinus (4.6%), Piceites (3.2%), Piceaepollenites (10.5%), Pinuspollenites (6.7%), Cedripites (1%), Podocarpidites (2.3%), Pristinuspollenites (0.5%), Caytonipollenites (0.1%), Quadraeculina (0.7%) and Erlianpollis (0.7%)
出处
《西北地质科学》
1992年第1期89-101,共13页
Northwest Geoscience
关键词
喇嘛湾组
孢子花粉
时代
志丹群
spores and pollen age Lamawan Formation northern Ordos basin
