Study On Fossil Woods Of The Upper Jurassic Tuchengzi Formation In Yanqing,Beijing

The Upper Jurassic Tuchengzi Fm.in Qianjiadian area of Yanqing,Beijing is one of the important Jurassic fossil wood-bearing strata for the North China Jurassic Flora,with a large number of in situ buried petrified woods(exposed a total of 57 trunks),all belonging to the conifer of Gymnosperms.Based on the literature reading and field fossil data collection,this paper carries out a systematic paleontological study on the petrified woods in the study area,the major results are as follows:1,This paper describes 1 genera and 2 species,i.e.,Xenoxylon peidense Zheng et Zhang and Xenoxylon conchylianum Fliche.And a large number of flat or curved fungal hyphae fossils in the petrified woods are firstly discovered in the study area.These hyphae are irregularly branched in different directions,with typical clamp-connection,which are inferred to be Basidiomycetes.This discovery enriches the evidence for the interactions between fungi and plants in the Jurassic trees.2,A detailed study is carried on the fossils of Xenoxylon Gothan,based on the study of clear growth rings in fossils,it indicates that the Late Jurassic period in the study area was of distinct seasonality;meanwhile,the tree heights are measured and estimated,the average tree height is about 25 m,indicating there were flourishing and high forest communities in the study area.In addition,the annual sensitivity and mean sensitivity are calculated,respectively mostly below 0.3 and all below 0.3,showing a cool and humid climate in the Late Jurassic age in the study area.which is coincident with that marked by Xenoxylon Gothan.3,Author also partially took part in the international cooperation project on petrified wood conservation,learnt and accumulated experiences on the general methods and procedures of petrified wood conservation,and provides some suggestions for similar conservation projects in China in future.