辽西早白垩世义县组Ruffordia和Nageiopsis的发现及其地层意义  

OCCURRENCE OF RUFFORDIA AND NAGEIOPSIS FROM THE EARLY CRETACEOUS YIXIAN FORMATION OF WESTERN LIAONING AND ITS STRATIGRAPHIC SIGNIFICANCE

作　　者：曹正尧[1] 

机构地区：[1]中国科学院南京地质古生物研究所,南京210008

出　　处：《古生物学报》2001年第2期214-218,共5页Acta Palaeontologica Sinica

基　　金：中国科学院资源与环境研究"九五"重大项目 !(KZ95 1 B1 410 )资助

摘　　要：报道辽西义县组两种颇具地层意义的植物化石 :Ruffordiagoeppertii (Dunker)Seward和Nageiopsisexgr.zamioides (Fontaine)Berry。根据植物化石认为义县组的时代应属于早白垩世。The fossil plants collected by the author in the past fifteen years from the Yixian Formation of western Liao-ning amount to about 20 genera, which are dominated by ginkgophytes (including such genera as Baiera, Sphenobaiera, Phoenicopsis, Czekanowskia, Solenites and Leptostrobus) and conifers (Pityolepis, Pityospermum, Schizolepis, Nageiopsis, Podozamites and Elatocladus), with less abundant sphenopsida (Equisetites), ferns (Ruffordia, Coniopteris, Acanthopteris?, Clado-phlebis) and cycadophytes (Tyrmia), as well as some problematic angiosperms. This assemblage is very similar in general aspect to the Early Cretaceous flora of Mongolia (Krassilov, 1982), and also comparable in floristic composition to the Early Cretaceous floras of Siberia which are characterized especially by abundant Dicksoniaceae, besides ginkgophytes and conifers. The most significant for dating the strata is the presence of Ruffordia and Nageiopsis in the present collection. This paper is to describe Ruffordia goeppertii (Dunker) Seward and Nageiopsis ex gr. zamioides (Fontaine) Berry. The former is an important element of Early Cretaceous floras in Laurasia, while the latter was firstly recorded by Fontaine (1889) from the Lower Cretaceous Potomac Group of eastern America, and later on it also has been described by Seward (1895) from the Wealden flora, Oishi (1940) from the Lower Cretaceous Ryoseki Formation in Japan, Bell (1956) from the Lower Cretaceous Bairmore Group of western Canada and Kryshtofovich and Prynada (1932) from the Lower Cretaceous Nikan Group. The Yixian Formation of western Liaoning should, therefore, belong to Early Cretaceous on the evidence of fossil plants.

关 键 词：Ruffordia Nageiopsis 义县组 早白垩世 辽宁西部 植物化石 

分 类 号：P534[天文地球—古生物学与地层学] Q914.2[天文地球—地质学]