Marine red beds occur frequently in China through geological time.Despite their complex environments,the red beds are found in three depositional settings:1) oceanic,deep water,as in the Upper Cretaceous of southern Tibet;2) outer shelf,deeper water,as in the Lower-Middle Ordovician of South China;and 3) inner shelf,shallow water,as in the Silurian and Triassic in South China.The Silurian marine red beds are recurrent in the lower Telychian,upper Telychian,and upper Ludlow.This paper is to document the marine nature of the lower Telychian red beds (LRBs) in the Upper Yangtze Region and to discuss the spatial and temporal distribution of the LRBs and their depositional environments.The LRBs are best developed on the north side of the Cathaysian Oldland,which can be interpreted as the source area.It is inferred that they were deposited during a marine regression,characterized by the lack of upwelling,low nutrition and organic productivity with a decrease of biodiversity and a high rate of sedimentation.The iron-rich sediments may have been transported by rivers on the oldland into the Upper Yangtze Sea,as rates of deposition were rapid enough to counteract normal reducing effect around sediment-water interface.The LRBs are different from the off-shore,deeper water red beds of lower Telychian in Avalonia and Baltica and further from the oceanic,deep water red beds of Upper Cretaceous in southern Tibet chiefly in palaeogeographic settings,biotic assemblages and marine environments.
Nanjinganthus is an Early Jurassic angiosperm recognized based on the study of over 200 specimens.However,some other authors have misinterpreted these fossils.Here the authors try to remedy the problems,by pointing out the logical pitfalls in these publications and underscoring a long-used,workable criterion for early angiosperms.The paper explains the cons and pros of this criterion,hoping to bring palaeobotany and plant taxonomy back to a consistent and practical track.Nanjinganthus is an angiosperm.
Qiang FuJoséB.DiezMike PoleManuel García-ÁvilaXin Wang
Noeggerathiales are an extinct group of sporebearing plants of uncertain systematic position that are known from Carboniferous and Permian age Euramerican and Cathaysian floras that occurred in present-day Europe,North America,and East Asia.The order Noeggerathiales includes over 50 species of more than 20 fossil genera,but their paleoecology is not well understood yet.Previously this group had been found only in extrabasinal floras or those inhabiting clastic wetlands.Noeggerathiales have never been recorded in coal ball floras.Thus,it is up to now uncertain whether this group has contributed to the formation of coal.Recent investigations of an Early Permian peat-forming flora of the Taiyuan Formation near Wuda,Inner Mongolia,which was preserved in a volcanic ash fall has provided evidence that noeggerathialean plants not only existed in the peat-forming vegetation but could even be the dominant group in some areas of the coal swamp.The Noeggerathiales in this particular peat-forming forest include Tingia unita,Paratingia wudensis,and a new species of Paratingia.Exceptionally well-preserved specimens indicate that these noeggerathialean plants are small trees with a canopy of compound leaves and strobili near the top of an unbranched(monocaulous)stem.
A fossil oak species,Quercus tenuipilosa Q.Hu et Z.K.Zhou,is reported from the upper Pliocene Ciying Formation in Kunming,Yunnan Province,southwestern China.The establishment of this species is based on detailed morphologic and cuticular investigations.The fossil leaves are elliptic,with serrate margins on the apical half.The primary venation is pinnate,and the major secondary venation is craspedodromous.The tertiary veins are opposite or alternate-opposite percurrent with two branches.The stomata are anomocytic,occurring only on the abaxial epidermis.The trichome bases are unicellular or multicellular.The new fossil species shows the closest affinity with theextant Q.delavayi and the late Miocene Q.praedelavayi Y.W.Xing et Z.K.Zhou from the Xiaolongtan Formation of the Yunnan Province.All three species share similar leaf morphology,but differ with respect to trichome base and stomatal densities.Q.tenuipilosa.Q.praedelavayi,and Q.delavayi can be considered to constitute the Q.delavayi complex.Since the late Miocene,a gradual reduction in trichome base density has occurred in this complex.This trend is the opposite of that of precipitation,indicating that increased trichome density is not an adaptation to dry environments.The stomatal density(SD)of the Q.delavayi complex was the highest during the late Miocene,declined in the late Pliocene,and then increased during the present epoch.These values show an inverse relationship with atmospheric CO_2 concentrations,suggesting that the SD of the Q.delavayi complex may be a useful proxy for reconstruction of paleo-CO_2 concentrations.
Compaction rates of sediments or volcaniclastic material are needed to reconstruct original thickness of a bed,which in turn is required to reconstruct subsidence rates,sea-level rise,or in the case of volcaniclastic,the location or direction of the eruption site.The knowledge of compaction rates can also aid in the reconstruction of deformed fossils.The known shape of deformed fossils can allow the determination of the compaction they experienced.Here we report the compaction rate in an early Permian volcanic tuff from Wuda,Inner Mongolia,determined from the deformation of standing tree fern stems of known anatomy.The compaction rate has been found to be 0.56 in this case,indicating that 44% of original thickness remains.
WANG JunHE XuezhiHermann W.PFEFFERKORNWANG Jinrong
Fossil ferns are abundant and diverse in the Permian Cathaysian Flora of Shanxi, North China. Although plants assemblages of the Carboniferous and Permian have been extensively investigated, their palaeoecology and especially the paleoecology of ferns has not been studied in detail. Recent reinvestigation of Oligocarpia gothanii has revealed its growth habit and cloning reproduction strategy, but most previous studies lack integrated sedimentological and taphonomic data. In this study, new materials of O. gothanii have been collected from a floodplain setting in the middle Permian Lower Shihhotse Formation of southeastern Shanxi. These plant fossils were found in a lenticular claystone associated with rooting structures. They are characterized by aphlebia at the base of the penultimate rachis. Sedimentological, taphonomic and morphological analyses were conducted to understand the growth habit and ecology of the fern. The result indicates that the Oligocarpia gothanii had a prostrate, ground cover growth habit, and was dominant in pioneer floras that colonized disturbed floodplains.
HE XuezhiWAN MingliYAN MengxiaoCHENG ChenWANG ShijunWANG Jun
