陕西榆林地区中侏罗统延安组孢粉组合及聚煤环境探讨  

Study on Sporo -pollen Assemblage and Coal -accumulating Environment of the Middle Jurassic Yan'an Formatiom in Yuling Region, Shaanxi Province

作　　者：闫存凤[1] 袁剑英[1] 

机构地区：[1]中国科学院兰州地质研究所

出　　处：《沉积学报》1993年第3期37-43,共7页Acta Sedimentologica Sinica

摘　　要：本文研究了陕西榆林地区ZK1534钻孔中侏罗统延安组孢子花粉66属103种,建立了该区延安组孢粉组合,对孢粉组合中主要孢子花粉的亲缘关系及古生态进行深入研究,利用孢粉生态类型百分含量、孢粉分异度值、结合孢粉植物群兴衰演替、沉积环境等因素,探讨了该区中侏罗世延安期聚煤古气候环境。Ordos Basin is one of the largest coal-bearing basin in China. In this paper. 103 species of spores and pollen grains referred to 60 genera, form the Yan'an Formation, the Middle Jurassic coal series of ZK1534 dril Ihole in Yuling region of this basin, have been studied. In the sporo - pollen assemblage of the formation, the percentage of pteridophyta spores amounts to 60. 4%, the pollen grains of gymnospermae to 39. 5%. Among the spores, Cyathididtes and Delloidospora are predominant (33. 1%). Osmundacidites (3. 0%), Duplexisporites (3.2%), Converrucosisporites (2.7%), Neoraistrickia (2.2%), Cibotiumspora (1. 6%), and Lycopdiumsporites (0. 6%) are comparatively abundant. Among the pollen grains, Cycadopitts (26. 7%) is the most important, the rest pollen grains only have small amount. By studing sporo -pollen assemblage, in terms of actuopaleontology and the ecoenvironment of the affiliated plants, the main spores and pollen (over 1 % on average) could be divided into three ecotypes: (a) Hu-midophytes, representative dispersed sporo -pollen are Lycopodiumsportes, Neoraistridia, Calamospora. Osmundacidites, Duplexisporites and Steresporites. (b) Humidomesophytes, are Delloidospora, Cyathidites, Ci- botiumspora and Converrucosisporites. (c) Arid - mesophytes, are Cyca dopites and Disaccites. Besides this, the percentage of each ecotype and diversity (by) D=N(N -1)/∑ Ni (ni -1) of sporo -pollen are calculated. The ecotype and diversity can be used as main ecoelements to reflecte the palaeoclimate. The former might be the main result of humidity changes and the later might reflect the variation of humidity and temperature. When the humidity and temperature are more suitable to the plant comunity developing and its species flourishing, the diversity might be maximum, and if the circumstance is contrary to above, the diversity might decrease. Morever, the sedimentary environment is considered. All these studing results show that the palaeoclimate of the Middle Jurassic pe

关 键 词：孢子花粉 聚煤环境 中侏罗世 地层 

分 类 号：P618.110.2[天文地球—矿床学]