再论道虎沟生物群的时代

On the Geological Age of Daohugou Biota

内蒙古宁城道虎沟地区的晚中生代地层十分发育,产状平缓,主要为一套产有丰富动、植物化石的凝灰质泥岩和粉砂岩,并夹有数层火山岩。从区域上来看,在西台子一带主要为早白垩世义县组的地层,产有丰富的热河生物群的化石,常见者有鱼类Lycoptera davidi,Peipiaosteus pani,Yanosteus longidorsalis,Protopsephurus liui和鸟类Confuciusornis sanctus;但在道虎沟—小西沟一带主要为中—晚侏罗世髫髻山组的地层,产有丰富的道虎沟生物群的化石,常见者有蝾螈Jeholotriton paradoxus和Chunerpeton tianyiensis,翼龙Jeholopterus ningchengensis和Pterorhynchus wellnhoferi,手盗龙类Scansoriopteryx heilmanni和(?)Pedopennadao hugouensis[本文对Xu等(2005)描述的道虎沟足羽龙(Pedopenna daohugouensis)的原始产地存有疑义],昆虫Meso baetis sibirica,Mesone taantiqua,Rhipidoblattina(Cana liblatta)hebeiensis,Brunneus haifanggouensis,Palaeontinodes haifanggouensis等,叶肢介Euestheria ziliujingensis,E.haifanggouensis,E.jingyuanensis和E.luanpingensis,植物Cladophlebis(Osmunda?)sp.,Anomozamites angulatus,A.(Trymia?) sp.,Cycadolepissp.,Ginkgoites sp.,Pityospermus sp.,Pityocladussp.,Zamites gigas,Yanliaoia sinensis和Coniopteris burejensis等。根据区域地质构造、地层分布、生物群特征和地质年代学资料分析,笔者确信道虎沟生物群的时代为中—晚侏罗世(卡洛夫阶—牛津阶),根本不可能将其归于早白垩世热河生物群。

The Late Mesozoic strata in the Daohugou area of Ningcheng,Inner Mongolia are well developed with rich fossils, which are composed of tuffaceous mudstones and siltstones and interbedded with volcanic rocks. Regionally, in the Xitaizi area are distributed Early Cretaceous beds of Yixian Formation, yielding rich fossils of Jehol Biota, such as L ycoptera davidi , Peipiaosteus pani , Yanosteus longidorsalis , Protopsephurus liui （fishes） and Confuciusornis sanctus （birds）. In the Daohugou area, however, are distributed Middle--Late Jurassic strata of Tiaojishan Formation, yielding very rich fossils of Daohugou Biota, such as Jeholotriton paradoxus and Chunerpeton tianyiensis （ salamanders ）, Jeholopterus ningchengensis and Pterorhynchus wellnhofeni （ pterosaurs ）, Scansoriopteryx heilrnanni and （？） Pedopenna daohugouensis （ Maniraptora, theropods ）, Mesobaetis sibirica, Mesoneta antiqua, Rhipidoblattina （Canaliblatta） hebeiensis, Brunneus haifanggouensis, Palaeontinodes haifanggouensis and others （insects）, Euestheria ziliujingensis, E. haifanggouensis, E. jingyuanensis and E. luanpingensis （conchostracans）, Cladophlebis （Osmunda ？） sp., Anomozarnites angulatus, A. （Trymia ？） sp. , Cycadolepis sp. , Ginkgoites sp. , Pityosperrnus sp. , Pityocladussp. , Zamites gigas, Yanliaoia sinensis and Coniopteris burejensis （plants）. According to our current study, Daohugou Biota is surely considered to be of an age of Middle-Late Jurassic （Callovian-Oxfordian）, rather than Early Cretaceous.