Discovery of Fossil Charophytes from the Late Triassic Xujiahe Formation and Early Jurassic Lower Yimen Formation, Sichuan Province, and Its Significance

This paper describes the fossil charophytes collected from the Late Triassic Xujiahe Formation in Dazuand Early Jurassic Lower Yimen Formation in Xichang, Sichuan Province, and their significance. Up to now,papers dealing with fossil charophytes of the Late Triassic, especially of the Early Jurassic, have been rarelypublished. The description of the two new species of Porochara, P. dazuensis and P. xichangensis, and theirfossil assemblage not only provides an important basis for classification and correlation of red beds insouthwestern China but reveals for the first time the features of the charophyte flora of the Late Triassic-EarlyJurassic in the area, thus offering valuable data for the establishment of Triassic and Jurassic charophyte fossilzones in China.

Permian–Triassic Charophytes: Distribution, Biostratigraphy and Biotic Events

Permian charophytes are known from the Ukraine, Russia, Kazakhstan, Germany, Saudi Arabia, China, the USA, Brazil, Paraguay and India. Most of these records are of Middle- Late Permian Age and are the basis of local biostratigraphic zonation in southern Russia and China. Development of a robust Permian charophyte biostratigraphy will require a more extensive record. Triassic charopbytes are known from Germany, Sweden, Poland, Slovenia, Bulgaria, the Ukraine, Russia, Morocco, Congo, the USA, Argentina, Kazakhstan and China. This encompasses records from all Triassic stages and has been the basis of detailed biostratigraphic zonation in southern Russia-Kazakhstan-eastern Europe. Permian and Triassic charophyte biostratigraphy at the level of genus does not provide detailed correlations beyond local or regional schemes. Nevertheless, it does identify some important evolutionary datums that constrain the timing of important biotic events in the Permian-Triassic evolutionary history of the Charophyta, including： （1） Early Permian extinction of the Palaeocharaceae; （2） Late Permian extinction of the ＂Trochiliscales＂ （Moellerinales）; （3） Carboniferous origin of the paraphyletic Porocharaceae, soon followed during the Permian by the origin of the multicellular basal plate; and （4） an important generic turnover of charophytes across the Triassic-Jurassic boundary, though there are insufficient data to identify this as a mass extinction.

Phytoremediation potential of charophytes:Bioaccumulation and toxicity studies of cadmium,lead and zinc

The ability for usage of common freshwater charophytes,Chara aculeolata and Nitella opaca in removal of cadmium （Cd）,lead （Pb） and zinc （Zn） from wastewater was examined.C.aculeolata and N.opaca were exposed to various concentrations of Cd （0.25 and 0.5 mg/L）,Pb （5 and 10 mg/L） and Zn （5 and 10 mg/L） solutions under hydroponic conditions for 6 days.C.aculeolata was more tolerant of Cd and Pb than N.opaca.The relative growth rate of N.opaca was drastically reduced at high concentrations of Cd and Pb although both were tolerant of Zn.Both macroalgae showed a reduction in chloroplast,chlorophyll and carotenoid content after Cd and Pb exposure,while Zn exposure had little effects.The bioaccumulation of both Cd and Pb was higher in N.opaca （1544.3 μg/g at 0.5 mg/L Cd,21657.0 μg/g at 10 mg/L Pb） whereas higher Zn accumulation was observed in C.aculeolata （6703.5 μg/g at 10 mg/L Zn）.In addition,high bioconcentration factor values （〉 1000） for Cd and Pb were observed in both species.C.aculeolata showed higher percentage of Cd and Pb removal （〉 95%） than N.opaca and seemed to be a better choice for Cd and Pb removal from wastewater due to its tolerance to these metals.

Middle Jurassic—Tertiary Deposits and Ostracod—Charophyte fossil assemblages of Xining and Minhe Basins

The Xining and the Minhe Basins bordering on each other around Ledu innorthwestern China cover a wide area from the west of Lanzhou in Gansuprovince to the east of Xining in Qinghai province.In these inland basins,Meso-Cenozoic terrestrial deposits about 6000-7000 meters in thicknessand rich in mineral resources,such as coal,oi1 as well as salts,had beenaccumunated,which yield abundant organic remains comprising microfossils,such as nonmarine ostracods,charophytes,spores and pollen and macrofos-si1s including bivalves.gastropods,esthierians,fishes,reptiles and plants.

Research on the disappearance causes of the Tenghualuo Site in Lianyungang,Jiangsu Province, China

With brilliant civilization during the transitional period from a original clan society to a state society in prehistory,the Neolithic Tenghualuo Site in Lianyungang was discovered by archaeological survey in 1989,which was titled as‘one of the nation’s ten great archeological discoveries in 2000’.However,the transgression and the anthropogenic environment deterioration have ever been employed to explain the abandonment of the site.Based on a dynasty framework established by the 14 C dating,and using the experimental methods such as micro-paleontology identification in foraminifera and charophytes, the content test of Rb and Sr,susceptibility analysis as well as granularity and sedimentary facies analysis,some researches on the sediments from the two exploration layers at Tenghualuo Site were conducted,and the following new findings have been gained:Firstly,foraminifera which are relevant to the marine environment were not found in the sediment layer,however,25 charales,which usually live in the freshwater environment,in 07LTT1 exploration samples were found.Among them,3 charales were found in the samples from the forth sediment layer below the late Longshan Cultural layer and 22 charates were from the second sediment layer above the late Longshan Cultural layer.Furthermore,5 plant seeds and 41 fungal spores,together with many carbonation holes,plant seed shells,as well as their roots and stems were also found in the second sediment layer above the late Longshan Cultural layer.Secondly,the cumulative probability curves of the sediments’granularity in both the last and its overlying culture intermittent layers have characteristics of three-phase river sediment curve,and the ratios between Rb and Sr are both quite high in samples from two layers sedimented during the disappearing time of the site.All above-mentioned evidences indicate that disappearance of the Tenghualuo Site was not related to the transgression.The late Longshan Culture of the site could be completely abandoned after a relatively long-term inland water flood.

A potential stratotype for the regional lowermost stage of the continental Paleocene in China

Phanerozoic chronostratigraphic units can only be defined through their lower boundary stratotypes.The lowermost stage of the Paleocene of China,which mainly consists of terrestrial deposits,can only be defined through its lower boundary stratotype,i.e.the continental Cretaceous/Paleogene boundary stratotype.There is no section yet found which contains continuous terrestrial deposits and biostratigraphic records of the Cretaceous-Paleogene transition in Nanxiong,Guangdong and Jiayin,Heilongjiang,there is no evidence for establishing the continental stratotype of the Cretaceous/Paleogene boundary in either area.Therefore,both the"Shanghuan stage"and"Furaoan stage"are not good candidates for the lowermost stage of the Paleocene of China.From the viewpoint of charophytes,the outcrop section of the Dangyang,Hubei Province(Central China)contains the most continuous,abundant and diverse terrestrial biostratigraphic records of the Cretaceous-Paleogene transition,in particular the early Paleocene,known so far in the world.The biostratigraphic records of ostracods in the transition are also continuous,rich,and diverse.The Dangyang outcrop section is the only section known so far in China that is a possible candidate for a continental stratotype of the Cretaceous/Paleogene boundary in China and the section is the only potential section identified to date for establishing the regional lowermost stage of the Paleocene,Paleogene and Cenozoic in China or stratotype section for the stage.