Recent geological and paleontological exploration in the Indus basin of Pakistan allowed the discoveries of numerous remains of non-marine reptiles( titanosaurian sauropod,abelisaurian and noasaurian theropod dinosaur...Recent geological and paleontological exploration in the Indus basin of Pakistan allowed the discoveries of numerous remains of non-marine reptiles( titanosaurian sauropod,abelisaurian and noasaurian theropod dinosaurs),and marine reptiles( crocodiles),flying reptiles( pterosaurs),marine and non-marine mammals,fishes,invertebrates,and plants,especially Pakistan is relatively rich in footprints / trackways in the Mesozoic.These vertebrates of Indo-Pakistan are very significant for paleobiogeographic study due to the present-day connection of this continent with Asia in Northern Hemisphere,whereas during past( Jurassic and pre-Jurassic) it was connected to the Gondwana. The Mesozoic vertebrates show close affinities with Gondwanan landmasses.The Cenozoic vertebrates show Eurasian affinity and migrated from Indo-Pak subcontinent to Eurasia or vice versa via Paleo Indus River systems along Western Indus Suture,after long journey of about 6 000 km the first collision of Indo-Pak subcontinent with Asia occurred at terminal Cretaceous.展开更多
During the early two decades of third millennium, many Mesozoic and Cenozoic biotas belong to plesiosaur, Titanosauriformes, titanosaurs, theropods, Mesoeucrocodiles, pterosaur, bird, snake, fishes, mammals, eucrocodi...During the early two decades of third millennium, many Mesozoic and Cenozoic biotas belong to plesiosaur, Titanosauriformes, titanosaurs, theropods, Mesoeucrocodiles, pterosaur, bird, snake, fishes, mammals, eucrocodiles, invertebrates and plants from Pakistan were found. Previously a few were formally published according to nomenclatural rules. Most of the Mesozoic vertebrates were formally published in August 2021, and the remaining Mesozoic and Cenozoic biotas are being formally described here.展开更多
Saraikistan (South Punjab and surrounding) area of Pakistan is located in the central Pakistan. This area represents Triassic-Jurassic to Recent sedimentary marine and terrestrial strata. Most of the Mesozoic and Earl...Saraikistan (South Punjab and surrounding) area of Pakistan is located in the central Pakistan. This area represents Triassic-Jurassic to Recent sedimentary marine and terrestrial strata. Most of the Mesozoic and Early Cenozoic are represented by marine strata with rare terrestrial deposits, while the Late Cenozoic is represented by continental fluvial deposits. This area hosts significant mineral deposits and their development can play a significant role in the development of Saraikistan region and ultimately for Pakistan. The data of recently discovered biotas from Cambrian to Miocene age are tabulated for quick view. Mesozoic biotas show a prominent paleobiogeographic link with Gondwana and Cenozoic show Eurasian. Phylogeny and hypodigm of Poripuchian titanosaurs from India and Pakistan are hinted at here.展开更多
The Devonian System in the Qinghai-Tibetan Plateau and its surrounding areas is widely distributed,diverse in lithotypes and rich in fossils.It records the crucial processes of continuous subduction and reduction of t...The Devonian System in the Qinghai-Tibetan Plateau and its surrounding areas is widely distributed,diverse in lithotypes and rich in fossils.It records the crucial processes of continuous subduction and reduction of the Paleo-Asian Ocean in the northern hemisphere and the transformation of the Proto-Tethys Ocean into the Paleo-Tethys Ocean in the southern hemisphere.Thus,it is of great significance for explaining the global paleogeographic evolution,tectonic activities and biodiversity changes during this critical period.The blocks on both sides of the southern Tienshan suture zone and the Longmu Co-ShuanghuChangning-Menglian suture zone belong to different sedimentary systems and paleobiogeographic realms and regions,showing important tectonic paleogeographic partitioning significance.The two suture zones represent the main branches of the PaleoAsian Ocean and the Paleo-Tethys Ocean,respectively,and on this basis the Devonian System can be subdivided into three types:the Tienshan type,the Tethys type and the Gondwana type.Based on recent research progress on the Devonian stratigraphy and paleontology in combining provenance analysis and biotic characteristics in the Qinghai-Tibetan Plateau and surrounding areas,this paper aims to establish the latest integrative stratigraphic framework and conduct paleogeographic reconstruction,providing foundation for exploring the geological evolution and dynamic mechanisms of various terranes and blocks in the northern margin of Gondwana.The results indicate that the North Qiangtang,South Qiangtang,Simao,Baoshan and Tengchong terranes,as well as the Himalaya Tethys Zone and the South China Block have affinities with the Indian Block,while the Lhasa Terrane has affinities with the Australian Block,and may be located between the South China and Australian blocks.In the Emsian(Early Devonian),the South China Block separated from the northern margin of Gondwana,a process that was accompanied by the opening of the Jinshajiang-Ailaoshan Ocean.In the Middle Devonian,the mid-oceanic ridge of the Paleo-Tethys Ocean expanded rapidly,corresponding with a global sea-level rise,the widespread development of carbonate platforms and nadir values of Devonian seawater strontium isotopes.By the Late Devonian,the Paleo-Tethys Ocean had reached a considerable size,leading to abundant occurrences of Upper Devonian radiolarian cherts in the Paleo-Tethys suture zones.展开更多
The Permian Period was a critical time interval during which various blocks of the Qinghai-Tibetan Plateau have experienced profound and complex paleogeographical changes.The supercontinent Pangea was formed to its ma...The Permian Period was a critical time interval during which various blocks of the Qinghai-Tibetan Plateau have experienced profound and complex paleogeographical changes.The supercontinent Pangea was formed to its maximum during this interval,hampering a global east-to-west trending equatorial warm ocean current.Meanwhile,a semi-closed Tethys Ocean warm pool formed an eastward-opening oceanic embayment of Pangea,and became an engine fostering the evolutions of organisms and environmental changes during the Paleozoic-Mesozoic transition.Stratigraphy and preserved fossil groups have proved extremely useful in understanding such changes and the evolutionary histories of the Qinghai-Tibetan Plateau.Widely distributed Permian deposits and fossils from various blocks of the Qinghai-Tibetan Plateau exhibited varied characteristics,reflecting these blocks’different paleolatitude settings and drifting histories.The Himalaya Tethys Zone south to the Yarlung Zangbo suture zone,located in the northern Gondwanan margin,yields fossil assemblages characterized by cold-water organisms throughout the Permian,and was affliated to those of the Gondwanaland.Most of the exotic limestone blocks within the Yarlung Zangbo suture zone are Guadalupian(Middle Permian)to Early Triassic in age.These exotic limestone blocks bear fossil assemblages that have transitional affinities between the warm Tethys and cold Gondwanan regions,suggesting that they most probably represent seamount deposits in the Neo-Tethys Ocean.During the Asselian to Sakmarian(Cisuralian,also Early Permian),the Cimmerian microcontinents in the northern part of Gondwana preserved glacio-marine deposits of Asselian to Sakmarian,and contained typical Gondwana-type cold-water faunas.By the middle Cisuralian(~290-280 Ma),the Cimmerian microcontinents rifted off from the Gondwanaland,and drifted northward allometrically due to the active magmatism of the Panjal Traps in the northern margin of the Indian Plate.Two slices of microcontinents are discerned as a result of such allometic drifting.The northern Cimmerian microcontinent slice,consisting of South Qiangtang,Baoshan,and Sibuma blocks,drifted relatively quickly,and preserved widespread carbonate deposits and warm-water faunas since Artinskian.By contrast,the southern Cimmerian microcontinent slice,consisting of Lhasa,Tengchong,and Irrawaddy blocks,drifted relatively slowly,and were characterized by widespread carbonate deposits containing warm-water faunas of late Kungurian to Lopingian(Late Permian).As such,these blocks rifted off from the northern Gondwanan margin since at least the Kungurian.Thus,it can be inferred that these blocks were incorperated into the low latitude,warm-water regions later than the northern Cimmerian slice.Such discrepancies in depositional sequences and paleobiogeography imply that the rifting of Cimmerian microcontinents resulted in the formation of both Meso-Tethys and Neo-Tethys oceans during the Cisuralian.By contrast,the North Qiangtang block,because of its further northern paleogeographical position,contains warm-water faunas throughout the whole Permian Period that are affiliated well with the faunas from the South China,Simao,and Indochina blocks.Together,these blocks belonged to the members of the northern Paleo-Tethys Ocean.Thus,an archipelagic paleogeographical framework divided by Paleo-,Meso-,and Neo-Tethys oceans was formed,fostering a global biodiversity centre within the Tethys warm pool.Since most of the allochthonous blocks assembling the Qinghai-Tibetan Plateau were situated in the middle to high latitude regions during the Permian,they preserved most sensitive paleoclimate records of the Late Paleozoic Ice Age(LPIA),the Artinskian global warming event,and the rapid warming event at the end-Permian.Therefore,sedimentological and paleontological records of these blocks are the unique window through which we can understand global evolutions of tectonic movement and paleoclimate,and their impacts on spatiotemporal distributions of comtemporaneous biotas.展开更多
During the Carboniferous Period,the Qinghai-Tibetan Plateau and its surrounding areas were located in quite different paleogeographic positions with various sedimentary and biological types.It is important to systemat...During the Carboniferous Period,the Qinghai-Tibetan Plateau and its surrounding areas were located in quite different paleogeographic positions with various sedimentary and biological types.It is important to systematically compile and summarize the Carboniferous strata and biotas of the Qinghai-Tibetan Plateau and its surrounding areas,to establish an integrated stratigraphic framework for correlation,and to reconstruct the paleogeography for correctly understanding the breakup of the Gondwana Continent and the evolution of the Paleo-Tethys Ocean in the Late Paleozoic.The Carboniferous of the Qinghai-Tibetan Plateau and its surrounding areas can be subdivided into the Gondwanan,Cimmerian,and Tethyan types.The Gondwanan-type Carboniferous are distributed in the North Himalayan,Kangmar-Lhunze,and Zanda-Zumba regions of the South Tibet Subprovince and northern India-Pakistan Area,where only the Mississippian is developed and the biota is of Gondwanan affinity.The Cimmerian-type Carboniferous,which are found in the Baoshan,Tengchong,Coqen-Xainza,LhasaZayu,Nagqu-Biru,and South Qiangtang regions,as well as Shan-Thai and South Afghanistan-Pamir areas,also represent only the Mississippian strata,but their biota is characterized by mixed characters of European,South China,Australian,and North American types.The Tethyan-type Carboniferous are distributed in the Tanggula Mountains,Hoh Xil-Bayanhar,ChamdoHengduanshan,Tiekelike,West Kunlun,Karakorum,East Kunlun-Central Qinling,and Qilian regions,where the Carboniferous succession is well developed,and the biota is of warm-water Tethyan affinity.The biostratigraphical correlation of the Gondwanan-type and Cimmerian-type Carboniferous is based mainly on conodonts and additionally on brachiopods and rugose corals.The Mississippian of the Tethyan-type Carboniferous is correlated mainly by using rugose corals and brachiopods,whereas in the Pennsylvanian foraminifera(fusuline)and conodonts are regarded as primary fossil groups,subordinated by rugose corals and brachiopods.Adhering to the International standard chronostratigraphy of the Carboniferous,we have reconstructed a framework of the litho-and biostratigraphic subdivision and correlation of the Qinghai-Tibetan Plateau and its surrounding areas.Further studies should focus on isotope geochronology,geochemistry,paleoclimates,and paleoenvironments of the Carboniferous in the Qinghai-Tibetan Plateau and its surrounding areas.展开更多
The Cretaceous Period is a vital time interval in deciphering the evolutionary history of the Neo-Tethys Ocean and the convergence of different plates and blocks across the Qinghai-Tibetan Plateau.A detailed stratigra...The Cretaceous Period is a vital time interval in deciphering the evolutionary history of the Neo-Tethys Ocean and the convergence of different plates and blocks across the Qinghai-Tibetan Plateau.A detailed stratigraphic framework and paleogeographic patterns are the basis for understanding the evolution of the Neo-Tethys Ocean and the formation of the QinghaiTibetan Plateau.Here,the Cretaceous stratigraphy,biota,paleogeography,and major geological events in the Qinghai-Tibetan Plateau are analyzed to establish an integrative stratigraphic framework,reconstruct the paleogeography during the Cretaceous Period,and decode the history of the major geological events.The Cretaceous rocks of the Qinghai-Tibetan Plateau and its surrounding area are predominantly marine deposits,with a small amount of interbedded marine-terrestrial and terrestrial conponents.The Indus-Yarlung Tsangpo Suture Zone was responsible for the deposition of deep marine sediments dominated by ophiolite suites and radiolarian silicalite.To the south,the Tethys Himalayas and Indus Basin received marine sediments of varying depths and lithology;to the north,the Xigaze and Ladakh forearc basins are also filled with marine sediments.The Lhasa Block,Karakorum Block,western Tarim Basin,and West Burma block consist of shallow marine,interbedded marine-terrestrial,and terrestrial sediments.The Qiangtang Basin and other areas are dominated by terrestrial sedimentation.The Cretaceous strata of the Qinghai-Tibetan Plateau and its surrounding areas are widely distributed and diversified,with abundant foraminifera,calcareous nannofossils,radiolarians,ammonites,bivalves,and palynomorphs.On the basis of integrated lithostratigraphic,biostratigraphic,geochronologic,and chemostratigraphic analyses,we proposed herein a comprehensive stratigraphic framework for the Cretaceous Period of the eastern Neo-Tethys.By analyzing the Cretaceous biota of different biogeographic zones from eastern Neo-Tethys and its surrounding areas,we reconstructed the paleobiogeography of different periods of eastern NeoTethys.The Cretaceous paleogeographic evolution of the Qinghai-Tibetan Plateau and its surrounding areas can be divided into three phases:(1)gradual breakup of the Indian Plate from the Australia-Antarctica continent and the early collision phase of the Lhasa-Qiangtang blocks(145-125 Ma);(2)northward drift of the Indian Plate and the collision phase of the Lhasa-Qiangtang blocks(125-100 Ma);(3)rapid northward drift of the Indian Plate,formation of the Tarim-Tajik-Karakorum Bay,and early uplift of the Gangdise Mountains(100-66 Ma).The Indus-Tethys Himalayan biota underwent a transition from the cold-water type in the high latitudes of the southern hemisphere to the warm-water type near the equator from the Early Cretaceous to the MidCretaceous.The biodiversity and abundance of the eastern Neo-Tethys Ocean increased gradually in the Early Cretaceous,peaking in the Mid-Cretaceous,and decreased sharply during the late Late Cretaceous(late Maastrichtian).Along with the northward drift of the Indian Plate and subduction of the Neo-Tethys,the eastern Neo-Tethys and its surrounding areas experienced a series of major geological events,including the formation of the large igneous province,oceanic anoxia events,and mass extinction,etc.展开更多
The complex evolutionary history of the Qinghai-Tibetan Plateau and its surrounding areas,including the continental blocks(Indian,Lhasa,South Qiangtang,Tarim,Olongbuluk,Central Qilian,Alxa,North China,Yangtze,Central ...The complex evolutionary history of the Qinghai-Tibetan Plateau and its surrounding areas,including the continental blocks(Indian,Lhasa,South Qiangtang,Tarim,Olongbuluk,Central Qilian,Alxa,North China,Yangtze,Central Iran and Oman)and the orogenic belts between them,has long been the frontier in Earth science research.The Cryogenian and Ediacaran strata are extensively distributed in these blocks.Specifically,relatively complete Cryogenian and Ediacaran successions have been discovered in Oman,Indian,Yangtze,and Tarim blocks,while only the Ediacaran successions have been reported in Iran,the South Qiangtang,Central Qilian,Alxa,and North China blocks.Based on previous studies together with the integration of new materials and advancement obtained through the Second Tibetan Plateau Scientific Expedition and Research,this review aims to synthesize a correlative stratigraphic framework of the representative Cryogenian and Ediacaran sequences from the Qinghai-Tibetan Plateau and its surrounding areas.Furthermore,the Cryogenian and Ediacaran biotas and major geological events in these areas are comprehensively discussed in aspects of current research status.The results indicate that,in general,Ediacaran fossils of each area exhibit distinct features in preservation and assemblage composition,but the typical late Ediacaran fossils Cloudina and Shaanxilithes have been reported from most of these areas.In addition to the two global Cryogenian glaciations,late Ediacaran glaciogenic deposits are extensively recorded in the areas within and around the northern QinghaiTibetan Plateau(including the North China,Alxa,Central Qilian,Olongbuluk,and Tarim blocks,and the North Qilian Accretionary Belt),as well as central and southern Iran.However,further research is required to determine the age,distribution,and origin of these late Ediacaran glaciogenic deposits.Meanwhile,the middle Ediacaran DOUNCE/Shuram Excursion is widely documented in the Qinghai-Tibetan Plateau and its surrounding areas.The available data show that,after the break-up of the Rodinia supercontinent,most of the continental blocks in the areas were located along the northern margin of East Gondwana and a few(such as North China)were located between the Gondwana and Laurentia.In general,the paleogeographic evolution of most of these blocks during the Cryogenian and Ediacaran remains disputatious,necessitating further research to resolve the controversies surrounding their paleogeographic reconstruction models during this critical time interval.展开更多
The Qinghai-Tibetan Plateau and its surrounding areas have a long and complex tectonic evolutionary history.Cratons and blocks,such as northern India,Lhasa,Qiangtang,Qaidam and Central Qilian,and their in-between orog...The Qinghai-Tibetan Plateau and its surrounding areas have a long and complex tectonic evolutionary history.Cratons and blocks,such as northern India,Lhasa,Qiangtang,Qaidam and Central Qilian,and their in-between orogenic belts constitute the main part of the Qinghai-Tibetan Plateau.During the Cambrian Period,most of these cratons and blocks were on the northwestern periphery of Gondwana,and were associated with the surrounding blocks,e.g.Arabian,Central Iran,Afghanistan,Tarim,Alxa,North China,South China and Sibumasu through the Proto-Tethys Ocean.The Cambrian stratigraphic sequences on these stable blocks are composed of mixed siliciclastic and carbonate rocks deposited in the shallow-water marine environments,and contain the trilobite assemblages of shelf facies.The Cambrian stratigraphic sequences in the Qilian tectonic belts,however,are characterized by the intermediate-basic igneous rocks and silicates formed in the Proto-Tethys Ocean,and contain the trilobite assemblages of deep-water slope facies.Combining with previous data,field observations and newly discovered fossils through funding by the Second Tibetan Plateau Scientific Expedition and Research,the general characteristics of the Cambrian strata in different tectonic units of the Qinghai-Tibetan Plateau and its surrounding areas have been summarized in this paper.Furthermore,efforts have been made to subdivide and correlate the Cambrian strata across these areas by utilizing available biostratigraphic and geochronological data.As a result,a comprehensive litho-and biostratigraphy chart has been compiled.Finally,from the biogeographic perspective,this paper also provides a brief overview of the Cambrian paleogeographical reconstruction of the major tectonic blocks,and discusses the problems associated with the evolution of the ProtoTethys tectonic belt.展开更多
The Doushantuo Formation in South China was deposited after the Nantuo glaciation but before the evolution of complex Ediacaran metazoans. It contains multiple taphonomic windows, in its cherts, carbonaceous shales, a...The Doushantuo Formation in South China was deposited after the Nantuo glaciation but before the evolution of complex Ediacaran metazoans. It contains multiple taphonomic windows, in its cherts, carbonaceous shales, and phosphorites, onto the late Neoproterozoic biosphere. The phosphatic window is unusually clear; Doushantuo phosphorites at Weng’an (Guizhou Province) are known to exquisitely preserve a multitude of single-celled eukaryotes, muiticellular algae, and microscopic animals. Our recent survey reveals that, in addition to the now famous Weng’an locality, Doushantuo phosphorites at Baokang (Hubei), Chadian (Shaanxi), and Shangrao (Jiangxi) also contain diverse eukaryotes preserved at the cellular level. All these phosphorites were deposited in shallow-water environments, typically above fair weather wave base and close to ancient islands. Along with Doushantuo cherts and shales, these phosphorites give us a clearer and more complete picture of late Neoproterozoic biological evolution: there展开更多
The Jiangchuan Biota from the Jiucheng Member(Mb.)of the Dengying Formation(Fm.),discovered in Jiangchuan,eastern Yunnan,China,is marked by copious macrofossils at the apex of the Ediacaran strata.This fauna features ...The Jiangchuan Biota from the Jiucheng Member(Mb.)of the Dengying Formation(Fm.),discovered in Jiangchuan,eastern Yunnan,China,is marked by copious macrofossils at the apex of the Ediacaran strata.This fauna features benthic algae with varied holdfasts and other fossils of indeterminate taxonomic affinity and is compositionally unique compared to the Shibantan and Gaojiashan biotas of the Dengying Fm.and the Miaohe and Wenghui biotas of the Doushantuo Fm.,elsewhere in China.One novel benthic saccular macroalgal fossil,named here Houjiashania yuxiensis gen.and sp.nov.,from the Jiangchuan Biota is based on fossils that are sausage-shaped,elongate,tubular,ranging from 0.3 to 4 cm in length,and up to 0.8 cm in diameter.One terminus is blunt and rounded to an obtuse angle,the other is bent with a spread-out surface resembling a holdfast,suggesting a three-dimensional thallus.Thin,stipe-shaped outgrowths,likely vestiges of sessile saccular life forms,are prevalent in macroalgal fossils of analogous size and shape,as well as present brown algae Scytosiphonaceae,such as Colpomenia and Dactylosiphon.The new findings augment the diversity of benthic algae,such as those known from the Early Neoproterozoic Longfengshan Biota in North China.The benthic algal macrofossils in the Jiucheng Mb.add to knowledge of Late Ediacaran metaphyte diversification and offer more clues about the evolutionary positioning of primitive macroalgae.The co-occurrence of numerous planktonic and benthic multicellular algae and planktonic microbes might have facilitated ecologically the more extensive later Cambrian explosion evidenced by the Chengjiang Biota in Yunnan.展开更多
Manadas Creek is an urban tributary of the Rio Grande that flows past a decommissioned antimony smelter and processing plant. This antimony plant is associated with heavy metal contamination in the creek and still pos...Manadas Creek is an urban tributary of the Rio Grande that flows past a decommissioned antimony smelter and processing plant. This antimony plant is associated with heavy metal contamination in the creek and still poses a threat to the surrounding aquatic environment. Corbicula fluminea was used to determine bioaccumulation from the water column and sediments in Manadas Creek. The metals arsenic (As), antimony (Sb) and thallium (Tl) were analyzed in the water, sediments, gills, mantle, foot, digestive (DI) tract, gonads and shell of clams being monitored at eight sites between March and August 2013. Sediment, water, and dissected Corbicula fluminea samples from different sites in the Creek were acid-digested and analyzed by Inductively Coupled Plasma Optical Emission Spectroscopy. High levels of antimony (25.88 ug/L;75.96 mg/kg) and arsenic (8.26 ug/L;6.41 mg/kg) in the water and sediments were observed at the site downstream from the smelter. There were no detectable concentrations of arsenic, antimony, or thallium in the shell of C. fluminea. Arsenic and antimony were detected in the tissues of C. fluminea but thallium was not detected. Based on the results, the organotropism for arsenic is DI tract > gills > gonads > foot > mantle > shell and the organotropism for antimony is gills > DI tract > gonads > mantle > foot > shell. This study shows that the Asiatic clam (Corbicula fluminea) is a useful bio-monitor to provide data on the status of metal pollution in Manadas Creek, Laredo, Texas.展开更多
Abundant and well-preserved remains of noncalcareous algae and soft-bodied metazoans were collected from Middle Cambrian Kaili biota in Taijiang county, Guizhou Province, China. These remains provide further evidence ...Abundant and well-preserved remains of noncalcareous algae and soft-bodied metazoans were collected from Middle Cambrian Kaili biota in Taijiang county, Guizhou Province, China. These remains provide further evidence for the wide geographic distribution of many Burgess Shale taxa. Among the algae, 5 genera (including two new genera) and 5 species are described. They are Marpolia spissa Walcott, Acinocricus stichus Conway Morris and Robison, Udotealga erecta Yang, Eosargassum sawata Yang, and Rhizophyton zhaoyuanlongii Yang. Contrasting the macroalgal fossil assemblage in the Kaili biota with one in the Burgess Shale biota, it is clear that similarity of the Kaili biota and the Burgess Shale biota is reflected by the same content of not only the soft-bodied metazoans, but also the noncalcareous algae.展开更多
The paper deals with a new species of megaalgal fossil-Enteromophites intestinalis sp. nov. found in Chenejiang Biota in the early Cambrian. A morphological comparison of the living Enteromorpha and fossil Enteromophi...The paper deals with a new species of megaalgal fossil-Enteromophites intestinalis sp. nov. found in Chenejiang Biota in the early Cambrian. A morphological comparison of the living Enteromorpha and fossil Enteromophites indicates that there probably is a close relationship between these two genera. Based on a study on the surroundings of living Enteromorpha, Enteromophites intestinalis sp. nov. might have lived in the environment of sea or salt water.展开更多
The extensive Late Mesozoic–Early Cenozoic sedimentary succession exposed within the James Ross Basin,Antarctica has huge potential to enhance paleobiological investigations into both the marine and terrestrial fossi...The extensive Late Mesozoic–Early Cenozoic sedimentary succession exposed within the James Ross Basin,Antarctica has huge potential to enhance paleobiological investigations into both the marine and terrestrial fossil records.In excess of 7 km in total thickness and spanning the Early Cretaceous(Aptian)–Late Eocene in age,it represents an invaluable high-latitude(~65°S)site for comparison with lower latitude,tropical ones in an essentially greenhouse world.The Early Cretaceous(Aptian–Albian)sequence is deep-water but there are indications of shallowing to inner shelf depths in both the Turonian and Coniacian stages.The first prolific shallow-water marine fauna occurs in the Santonian–Campanian Santa Marta Formation and this is followed by repeated occurrences through the later Campanian,Maastrichtian,Danian and Middle Eocene(Lutetian).In this study an attempt has been made to compare these Antarctic faunas directly with the well-known ones of the same age from the US Gulf Coast.Detailed comparisons made for three time slices,Late Maastrichtian,Danian and Middle Eocene,indicate that the Antarctic is characterised by both low taxonomic diversity and high levels of endemism.The James Ross Basin is providing important evidence to indicate that the highest southern latitudes have always been characterised by a distinctive temperate biota,even on a pre-glacial Earth.The roots of at least some elements of the modern Southern Ocean biota can be traced back to a Late Mesozoic–Early Cenozoic austral realm.展开更多
A Burgess Shale-type biota is, in part, characterized by a wide diversity of taxa and soft-part preservation. Each provides unique historical insights into early metazoan evolution. Among the more than 40 globally dis...A Burgess Shale-type biota is, in part, characterized by a wide diversity of taxa and soft-part preservation. Each provides unique historical insights into early metazoan evolution. Among the more than 40 globally distributed biotas, the early Cambrian Chengjiang and Middle Cambrian Burgess-type biotas are the largest. The Kaili Biota, from the earliest Middle Cambrian of Guizhou, China, contains representatives of 110 metazoan genera belonging to 10 phyla. It contains many well-persevered soft-bodied specimens. This Chinese biota has become the third most taxonomically diverse Burgess Shale-type fauna. Because the Kaili Biota formed in an outer-shelf environment, its main faunal character is large numbers of eocrinoids and planktoic trilobites. The Kaili is younger than the Chengjiang Biota but older than the Canadian Burgess Shale Biota; it shares 30 genera with the Chengjiang and 38 genera with the Burgess Biota. The Kaili Biota displays a taphonomic window to the diversification and evolution of marine offshore organisms covering 5.13 million years between the Early and Middle Cambrian.展开更多
After a slow recovery from the end-Permian extinction during the Early Triassic and rapid radiation in the Middle Triassic, evolution of organisms reached a new peak phase in the Late Triassic. The Guanling Biota from...After a slow recovery from the end-Permian extinction during the Early Triassic and rapid radiation in the Middle Triassic, evolution of organisms reached a new peak phase in the Late Triassic. The Guanling Biota from the Wayao Member （conodont Paragondolella polygnathiformis Zone）, Falang Formation, Xinpu, Guanling County, Guizhou Province, southwestern China corresponds to this peak that marks the full recovery from the end-Permian extinction of marine ecosystems. The biota is of high diversity, containing well preserved and completely articulated skeletons of vertebrates comprising marine reptiles, fishes, and invertebrates including crinoids, ammonites, bivalves, and other fossils, and is one of the best examples of marine ecosystem records in life history. The fossil marine reptiles and crinoids are most significant in this biota, especially the marine reptiles, which provide an important link between the Triassic Pacific and Tethys, and between Triassic basal forms and the Jurassic-Cretaceous marine top predators. The most remarkable fossils are the large completely articulated ichthyosaur skeletons up to and more than 10 m, and the first recorded thalattosaurs and placodonts in China. Following our review, of the 17 named reptilian taxa the eight listed here are considered to be valid： three ichthyosaurs （Qianichthyosaurus zhoui Li, 1999; Guizhouichthyosaurus tangae Cao and Luo in Yin et al., 2000, Guanlingsaurus liangae Yin in Yin et al., 2000）, three thalattosaurs （Anshunsaurus huangguoshuensis Liu, 1999, Xinpusaurus suni Yin in Yin et al., 2000, Xinpusaurus kohi Jiang et al., 2004）, and two placodonts （Sinocyamodus xinpuensis Li, 2000, Psephochelys polyosteoderma Li and Rieppel, 2002）. Mixosaurus guanlingensis Cao in Yin et al., 2000 might be a junior synonym of Qianichthyosaurus zhoui Li, 1999, and Cymbospondylus asiaticus Li and You, 2002 and Panjiangsaurus epicharis Chen and Cheng, 2003 might be junior synonyms of Guizhouichthyosaurus tangae Cao and Luo in Yin et al., 2000. It needs to re-describe the holotypes after a complete preparation for clarifying the taxonomic status of Typicusichthyosaurus tsaihuae Yu in Yin et al., 2000, Xinpusaurus bamaolinensis Cheng, 2003, Neosinosaurus hoangi （Zhou in Yin et al., 2000）, Wayaosaurus geei Zhou in Yin et al., 2000, Wayaosaurus bellus Zhou in Yin et al., 2000 and Placochelys ？ minutus Yin and Luo in Yin et al., 2000.展开更多
Exceptionally preserved fossils,such as those from Cambrian Burgess Shale-type fossil-Lagerstatten are critical because of their unique contributions to knowledge of the phylogenetic radiation and palaeoecological exp...Exceptionally preserved fossils,such as those from Cambrian Burgess Shale-type fossil-Lagerstatten are critical because of their unique contributions to knowledge of the phylogenetic radiation and palaeoecological expansion of metazoans during the Cambrian explosion.Critically,these deposits provide information that is usually unobtainable from shelly and skeletonized fossils alone.The Guanshan Biota(Cambrian Series 2,Stage 4)in the Yunnan Province of South China,has produced abundant and diverse,exquisitely preserved fossils that often retain soft tissues and organs.To date,most fossils from the Guanshan Biota have been collected from localities such as Gaoloufang and Gangtoucun,which have become inaccessible due to new urban expansions and constructions of residential buildings.Here we present the first report of soft bodied fossils from a new section at Kanfuqing,close to the Wulongqing village in Malong County,approximately 3 km east of the Wulongqing Formation stratotype section.Fossils retain soft morphology,and include brachiopods with delicate marginal setae,priapulids with well-preserved sclerites and vetulicolians with entire sections of body.In addition,this fauna includes rare occurrences of trilobites preserved with soft tissues replicated as pyrite pseudomorphs after weathering.This discovery represents an important palaeogeographical extension of soft-bodied fossils of the Guanshan fauna to the east of the Xiaojiang Fault(related to Tsinning tectonic movements ca.700 Ma).The fauna from the new Kanfuqing section is similar to that reported from the Wulongqing Formation west of the Xiaojiang Fault,and thus has significant implications for early Cambrian palaeogeography,faunal successions and palaeoenvironments of eastern Yunnan.展开更多
AIM： To identify the bacterial flora in conditions such as Barrett＇s esophagus and reflux esophagitis to determine if they are similar to normal esophageal flora. METHODS： Using broad-range 16S rDNA PCR, esophageal...AIM： To identify the bacterial flora in conditions such as Barrett＇s esophagus and reflux esophagitis to determine if they are similar to normal esophageal flora. METHODS： Using broad-range 16S rDNA PCR, esophageal biopsies were examined from 24 patients [9 with normal esophageal mucosa, 12 with gastroesophageal reflux disease （GERD）, and 3 with Barrett＇s esophagus]. Two separate broad-range PCR reactions were performed for each patient, and the resulting products were cloned. In one patient with Barrett＇s esophagus, 99 PCR clones were analyzed. RESULTS： Two separate clones were recovered from each patient （total = 48）, representing 24 different species, with 14 species homologous to known bacteria, 5 homologous to unidentified bacteria, and 5 were not homologous （〈97% identity） to any known bacterial 16S rDNA sequences. Seventeen species were found in the reflux esophagitis patients, 5 in the Barrett＇s esophagus patients, and 10 in normal esophagus patients. Further analysis concentrating on a single biopsy from an individual with Barrett＇s esophagus revealed the presence of 21 distinct bacterial species. Members of four phyla were represented, including Bacteroidetes, Firmicutes, Proteobacteria, and Actinobacteria. Microscopic examination of each biopsy demonstrated bacteria in intimate association with the distal esophageal epithelium, suggesting that the presence of these bacteria is not transitory. CONCLUSION： These findings provide evidence for a complex, residential bacterial population in esophageal reflux-related disorders. While much of this biota is present in the normal esophagus, more detailed comparisons may help identify potential disease associations.展开更多
文摘Recent geological and paleontological exploration in the Indus basin of Pakistan allowed the discoveries of numerous remains of non-marine reptiles( titanosaurian sauropod,abelisaurian and noasaurian theropod dinosaurs),and marine reptiles( crocodiles),flying reptiles( pterosaurs),marine and non-marine mammals,fishes,invertebrates,and plants,especially Pakistan is relatively rich in footprints / trackways in the Mesozoic.These vertebrates of Indo-Pakistan are very significant for paleobiogeographic study due to the present-day connection of this continent with Asia in Northern Hemisphere,whereas during past( Jurassic and pre-Jurassic) it was connected to the Gondwana. The Mesozoic vertebrates show close affinities with Gondwanan landmasses.The Cenozoic vertebrates show Eurasian affinity and migrated from Indo-Pak subcontinent to Eurasia or vice versa via Paleo Indus River systems along Western Indus Suture,after long journey of about 6 000 km the first collision of Indo-Pak subcontinent with Asia occurred at terminal Cretaceous.
文摘During the early two decades of third millennium, many Mesozoic and Cenozoic biotas belong to plesiosaur, Titanosauriformes, titanosaurs, theropods, Mesoeucrocodiles, pterosaur, bird, snake, fishes, mammals, eucrocodiles, invertebrates and plants from Pakistan were found. Previously a few were formally published according to nomenclatural rules. Most of the Mesozoic vertebrates were formally published in August 2021, and the remaining Mesozoic and Cenozoic biotas are being formally described here.
文摘Saraikistan (South Punjab and surrounding) area of Pakistan is located in the central Pakistan. This area represents Triassic-Jurassic to Recent sedimentary marine and terrestrial strata. Most of the Mesozoic and Early Cenozoic are represented by marine strata with rare terrestrial deposits, while the Late Cenozoic is represented by continental fluvial deposits. This area hosts significant mineral deposits and their development can play a significant role in the development of Saraikistan region and ultimately for Pakistan. The data of recently discovered biotas from Cambrian to Miocene age are tabulated for quick view. Mesozoic biotas show a prominent paleobiogeographic link with Gondwana and Cenozoic show Eurasian. Phylogeny and hypodigm of Poripuchian titanosaurs from India and Pakistan are hinted at here.
基金financially supported by the Second Tibetan Plateau Scientific Expedition and Research(Grant No.2019QZKK0706)。
文摘The Devonian System in the Qinghai-Tibetan Plateau and its surrounding areas is widely distributed,diverse in lithotypes and rich in fossils.It records the crucial processes of continuous subduction and reduction of the Paleo-Asian Ocean in the northern hemisphere and the transformation of the Proto-Tethys Ocean into the Paleo-Tethys Ocean in the southern hemisphere.Thus,it is of great significance for explaining the global paleogeographic evolution,tectonic activities and biodiversity changes during this critical period.The blocks on both sides of the southern Tienshan suture zone and the Longmu Co-ShuanghuChangning-Menglian suture zone belong to different sedimentary systems and paleobiogeographic realms and regions,showing important tectonic paleogeographic partitioning significance.The two suture zones represent the main branches of the PaleoAsian Ocean and the Paleo-Tethys Ocean,respectively,and on this basis the Devonian System can be subdivided into three types:the Tienshan type,the Tethys type and the Gondwana type.Based on recent research progress on the Devonian stratigraphy and paleontology in combining provenance analysis and biotic characteristics in the Qinghai-Tibetan Plateau and surrounding areas,this paper aims to establish the latest integrative stratigraphic framework and conduct paleogeographic reconstruction,providing foundation for exploring the geological evolution and dynamic mechanisms of various terranes and blocks in the northern margin of Gondwana.The results indicate that the North Qiangtang,South Qiangtang,Simao,Baoshan and Tengchong terranes,as well as the Himalaya Tethys Zone and the South China Block have affinities with the Indian Block,while the Lhasa Terrane has affinities with the Australian Block,and may be located between the South China and Australian blocks.In the Emsian(Early Devonian),the South China Block separated from the northern margin of Gondwana,a process that was accompanied by the opening of the Jinshajiang-Ailaoshan Ocean.In the Middle Devonian,the mid-oceanic ridge of the Paleo-Tethys Ocean expanded rapidly,corresponding with a global sea-level rise,the widespread development of carbonate platforms and nadir values of Devonian seawater strontium isotopes.By the Late Devonian,the Paleo-Tethys Ocean had reached a considerable size,leading to abundant occurrences of Upper Devonian radiolarian cherts in the Paleo-Tethys suture zones.
基金supported by the the Second Tibetan Plateau Scientific Expedition and Research(Grant No.2019QZKK0706)the National Natural Science Foundation of China(Grant Nos.91855205,42261144668,42293280)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB26000000)。
文摘The Permian Period was a critical time interval during which various blocks of the Qinghai-Tibetan Plateau have experienced profound and complex paleogeographical changes.The supercontinent Pangea was formed to its maximum during this interval,hampering a global east-to-west trending equatorial warm ocean current.Meanwhile,a semi-closed Tethys Ocean warm pool formed an eastward-opening oceanic embayment of Pangea,and became an engine fostering the evolutions of organisms and environmental changes during the Paleozoic-Mesozoic transition.Stratigraphy and preserved fossil groups have proved extremely useful in understanding such changes and the evolutionary histories of the Qinghai-Tibetan Plateau.Widely distributed Permian deposits and fossils from various blocks of the Qinghai-Tibetan Plateau exhibited varied characteristics,reflecting these blocks’different paleolatitude settings and drifting histories.The Himalaya Tethys Zone south to the Yarlung Zangbo suture zone,located in the northern Gondwanan margin,yields fossil assemblages characterized by cold-water organisms throughout the Permian,and was affliated to those of the Gondwanaland.Most of the exotic limestone blocks within the Yarlung Zangbo suture zone are Guadalupian(Middle Permian)to Early Triassic in age.These exotic limestone blocks bear fossil assemblages that have transitional affinities between the warm Tethys and cold Gondwanan regions,suggesting that they most probably represent seamount deposits in the Neo-Tethys Ocean.During the Asselian to Sakmarian(Cisuralian,also Early Permian),the Cimmerian microcontinents in the northern part of Gondwana preserved glacio-marine deposits of Asselian to Sakmarian,and contained typical Gondwana-type cold-water faunas.By the middle Cisuralian(~290-280 Ma),the Cimmerian microcontinents rifted off from the Gondwanaland,and drifted northward allometrically due to the active magmatism of the Panjal Traps in the northern margin of the Indian Plate.Two slices of microcontinents are discerned as a result of such allometic drifting.The northern Cimmerian microcontinent slice,consisting of South Qiangtang,Baoshan,and Sibuma blocks,drifted relatively quickly,and preserved widespread carbonate deposits and warm-water faunas since Artinskian.By contrast,the southern Cimmerian microcontinent slice,consisting of Lhasa,Tengchong,and Irrawaddy blocks,drifted relatively slowly,and were characterized by widespread carbonate deposits containing warm-water faunas of late Kungurian to Lopingian(Late Permian).As such,these blocks rifted off from the northern Gondwanan margin since at least the Kungurian.Thus,it can be inferred that these blocks were incorperated into the low latitude,warm-water regions later than the northern Cimmerian slice.Such discrepancies in depositional sequences and paleobiogeography imply that the rifting of Cimmerian microcontinents resulted in the formation of both Meso-Tethys and Neo-Tethys oceans during the Cisuralian.By contrast,the North Qiangtang block,because of its further northern paleogeographical position,contains warm-water faunas throughout the whole Permian Period that are affiliated well with the faunas from the South China,Simao,and Indochina blocks.Together,these blocks belonged to the members of the northern Paleo-Tethys Ocean.Thus,an archipelagic paleogeographical framework divided by Paleo-,Meso-,and Neo-Tethys oceans was formed,fostering a global biodiversity centre within the Tethys warm pool.Since most of the allochthonous blocks assembling the Qinghai-Tibetan Plateau were situated in the middle to high latitude regions during the Permian,they preserved most sensitive paleoclimate records of the Late Paleozoic Ice Age(LPIA),the Artinskian global warming event,and the rapid warming event at the end-Permian.Therefore,sedimentological and paleontological records of these blocks are the unique window through which we can understand global evolutions of tectonic movement and paleoclimate,and their impacts on spatiotemporal distributions of comtemporaneous biotas.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0706)the National Natural Science Foundation of China(Grant Nos.91955201,42172002)。
文摘During the Carboniferous Period,the Qinghai-Tibetan Plateau and its surrounding areas were located in quite different paleogeographic positions with various sedimentary and biological types.It is important to systematically compile and summarize the Carboniferous strata and biotas of the Qinghai-Tibetan Plateau and its surrounding areas,to establish an integrated stratigraphic framework for correlation,and to reconstruct the paleogeography for correctly understanding the breakup of the Gondwana Continent and the evolution of the Paleo-Tethys Ocean in the Late Paleozoic.The Carboniferous of the Qinghai-Tibetan Plateau and its surrounding areas can be subdivided into the Gondwanan,Cimmerian,and Tethyan types.The Gondwanan-type Carboniferous are distributed in the North Himalayan,Kangmar-Lhunze,and Zanda-Zumba regions of the South Tibet Subprovince and northern India-Pakistan Area,where only the Mississippian is developed and the biota is of Gondwanan affinity.The Cimmerian-type Carboniferous,which are found in the Baoshan,Tengchong,Coqen-Xainza,LhasaZayu,Nagqu-Biru,and South Qiangtang regions,as well as Shan-Thai and South Afghanistan-Pamir areas,also represent only the Mississippian strata,but their biota is characterized by mixed characters of European,South China,Australian,and North American types.The Tethyan-type Carboniferous are distributed in the Tanggula Mountains,Hoh Xil-Bayanhar,ChamdoHengduanshan,Tiekelike,West Kunlun,Karakorum,East Kunlun-Central Qinling,and Qilian regions,where the Carboniferous succession is well developed,and the biota is of warm-water Tethyan affinity.The biostratigraphical correlation of the Gondwanan-type and Cimmerian-type Carboniferous is based mainly on conodonts and additionally on brachiopods and rugose corals.The Mississippian of the Tethyan-type Carboniferous is correlated mainly by using rugose corals and brachiopods,whereas in the Pennsylvanian foraminifera(fusuline)and conodonts are regarded as primary fossil groups,subordinated by rugose corals and brachiopods.Adhering to the International standard chronostratigraphy of the Carboniferous,we have reconstructed a framework of the litho-and biostratigraphic subdivision and correlation of the Qinghai-Tibetan Plateau and its surrounding areas.Further studies should focus on isotope geochronology,geochemistry,paleoclimates,and paleoenvironments of the Carboniferous in the Qinghai-Tibetan Plateau and its surrounding areas.
基金supported by the National Key Research and Development Project(Grant No.2022YFF08008002)the National Natural Science Foundation of China(Grant Nos.42272035,42288201,42072001,and 42272027)+2 种基金the Second Qinghai-Tibetan Plateau Scientific Expedition(Grant No.2019QZKK0706)the 111 Introduction Program(Grant No.B20011)the International Geological Comparison Program(Grant No.IGCP679)。
文摘The Cretaceous Period is a vital time interval in deciphering the evolutionary history of the Neo-Tethys Ocean and the convergence of different plates and blocks across the Qinghai-Tibetan Plateau.A detailed stratigraphic framework and paleogeographic patterns are the basis for understanding the evolution of the Neo-Tethys Ocean and the formation of the QinghaiTibetan Plateau.Here,the Cretaceous stratigraphy,biota,paleogeography,and major geological events in the Qinghai-Tibetan Plateau are analyzed to establish an integrative stratigraphic framework,reconstruct the paleogeography during the Cretaceous Period,and decode the history of the major geological events.The Cretaceous rocks of the Qinghai-Tibetan Plateau and its surrounding area are predominantly marine deposits,with a small amount of interbedded marine-terrestrial and terrestrial conponents.The Indus-Yarlung Tsangpo Suture Zone was responsible for the deposition of deep marine sediments dominated by ophiolite suites and radiolarian silicalite.To the south,the Tethys Himalayas and Indus Basin received marine sediments of varying depths and lithology;to the north,the Xigaze and Ladakh forearc basins are also filled with marine sediments.The Lhasa Block,Karakorum Block,western Tarim Basin,and West Burma block consist of shallow marine,interbedded marine-terrestrial,and terrestrial sediments.The Qiangtang Basin and other areas are dominated by terrestrial sedimentation.The Cretaceous strata of the Qinghai-Tibetan Plateau and its surrounding areas are widely distributed and diversified,with abundant foraminifera,calcareous nannofossils,radiolarians,ammonites,bivalves,and palynomorphs.On the basis of integrated lithostratigraphic,biostratigraphic,geochronologic,and chemostratigraphic analyses,we proposed herein a comprehensive stratigraphic framework for the Cretaceous Period of the eastern Neo-Tethys.By analyzing the Cretaceous biota of different biogeographic zones from eastern Neo-Tethys and its surrounding areas,we reconstructed the paleobiogeography of different periods of eastern NeoTethys.The Cretaceous paleogeographic evolution of the Qinghai-Tibetan Plateau and its surrounding areas can be divided into three phases:(1)gradual breakup of the Indian Plate from the Australia-Antarctica continent and the early collision phase of the Lhasa-Qiangtang blocks(145-125 Ma);(2)northward drift of the Indian Plate and the collision phase of the Lhasa-Qiangtang blocks(125-100 Ma);(3)rapid northward drift of the Indian Plate,formation of the Tarim-Tajik-Karakorum Bay,and early uplift of the Gangdise Mountains(100-66 Ma).The Indus-Tethys Himalayan biota underwent a transition from the cold-water type in the high latitudes of the southern hemisphere to the warm-water type near the equator from the Early Cretaceous to the MidCretaceous.The biodiversity and abundance of the eastern Neo-Tethys Ocean increased gradually in the Early Cretaceous,peaking in the Mid-Cretaceous,and decreased sharply during the late Late Cretaceous(late Maastrichtian).Along with the northward drift of the Indian Plate and subduction of the Neo-Tethys,the eastern Neo-Tethys and its surrounding areas experienced a series of major geological events,including the formation of the large igneous province,oceanic anoxia events,and mass extinction,etc.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0706)the National Natural Science Foundation of China(Grant No.41921002)。
文摘The complex evolutionary history of the Qinghai-Tibetan Plateau and its surrounding areas,including the continental blocks(Indian,Lhasa,South Qiangtang,Tarim,Olongbuluk,Central Qilian,Alxa,North China,Yangtze,Central Iran and Oman)and the orogenic belts between them,has long been the frontier in Earth science research.The Cryogenian and Ediacaran strata are extensively distributed in these blocks.Specifically,relatively complete Cryogenian and Ediacaran successions have been discovered in Oman,Indian,Yangtze,and Tarim blocks,while only the Ediacaran successions have been reported in Iran,the South Qiangtang,Central Qilian,Alxa,and North China blocks.Based on previous studies together with the integration of new materials and advancement obtained through the Second Tibetan Plateau Scientific Expedition and Research,this review aims to synthesize a correlative stratigraphic framework of the representative Cryogenian and Ediacaran sequences from the Qinghai-Tibetan Plateau and its surrounding areas.Furthermore,the Cryogenian and Ediacaran biotas and major geological events in these areas are comprehensively discussed in aspects of current research status.The results indicate that,in general,Ediacaran fossils of each area exhibit distinct features in preservation and assemblage composition,but the typical late Ediacaran fossils Cloudina and Shaanxilithes have been reported from most of these areas.In addition to the two global Cryogenian glaciations,late Ediacaran glaciogenic deposits are extensively recorded in the areas within and around the northern QinghaiTibetan Plateau(including the North China,Alxa,Central Qilian,Olongbuluk,and Tarim blocks,and the North Qilian Accretionary Belt),as well as central and southern Iran.However,further research is required to determine the age,distribution,and origin of these late Ediacaran glaciogenic deposits.Meanwhile,the middle Ediacaran DOUNCE/Shuram Excursion is widely documented in the Qinghai-Tibetan Plateau and its surrounding areas.The available data show that,after the break-up of the Rodinia supercontinent,most of the continental blocks in the areas were located along the northern margin of East Gondwana and a few(such as North China)were located between the Gondwana and Laurentia.In general,the paleogeographic evolution of most of these blocks during the Cryogenian and Ediacaran remains disputatious,necessitating further research to resolve the controversies surrounding their paleogeographic reconstruction models during this critical time interval.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research(Grant No.2019QZKK0706)the National Natural Science Foundation of China(Grant No.41921002)。
文摘The Qinghai-Tibetan Plateau and its surrounding areas have a long and complex tectonic evolutionary history.Cratons and blocks,such as northern India,Lhasa,Qiangtang,Qaidam and Central Qilian,and their in-between orogenic belts constitute the main part of the Qinghai-Tibetan Plateau.During the Cambrian Period,most of these cratons and blocks were on the northwestern periphery of Gondwana,and were associated with the surrounding blocks,e.g.Arabian,Central Iran,Afghanistan,Tarim,Alxa,North China,South China and Sibumasu through the Proto-Tethys Ocean.The Cambrian stratigraphic sequences on these stable blocks are composed of mixed siliciclastic and carbonate rocks deposited in the shallow-water marine environments,and contain the trilobite assemblages of shelf facies.The Cambrian stratigraphic sequences in the Qilian tectonic belts,however,are characterized by the intermediate-basic igneous rocks and silicates formed in the Proto-Tethys Ocean,and contain the trilobite assemblages of deep-water slope facies.Combining with previous data,field observations and newly discovered fossils through funding by the Second Tibetan Plateau Scientific Expedition and Research,the general characteristics of the Cambrian strata in different tectonic units of the Qinghai-Tibetan Plateau and its surrounding areas have been summarized in this paper.Furthermore,efforts have been made to subdivide and correlate the Cambrian strata across these areas by utilizing available biostratigraphic and geochronological data.As a result,a comprehensive litho-and biostratigraphy chart has been compiled.Finally,from the biogeographic perspective,this paper also provides a brief overview of the Cambrian paleogeographical reconstruction of the major tectonic blocks,and discusses the problems associated with the evolution of the ProtoTethys tectonic belt.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 49902002 and 49972006)the Chinese Academy of Sciences(Grant No.KZCX2-116)the Major Basic Research Projects of Chinese Ministry of Science and Technology (Gran
文摘The Doushantuo Formation in South China was deposited after the Nantuo glaciation but before the evolution of complex Ediacaran metazoans. It contains multiple taphonomic windows, in its cherts, carbonaceous shales, and phosphorites, onto the late Neoproterozoic biosphere. The phosphatic window is unusually clear; Doushantuo phosphorites at Weng’an (Guizhou Province) are known to exquisitely preserve a multitude of single-celled eukaryotes, muiticellular algae, and microscopic animals. Our recent survey reveals that, in addition to the now famous Weng’an locality, Doushantuo phosphorites at Baokang (Hubei), Chadian (Shaanxi), and Shangrao (Jiangxi) also contain diverse eukaryotes preserved at the cellular level. All these phosphorites were deposited in shallow-water environments, typically above fair weather wave base and close to ancient islands. Along with Doushantuo cherts and shales, these phosphorites give us a clearer and more complete picture of late Neoproterozoic biological evolution: there
基金supported by the National Natural Science Foundation of China(Grant Nos.42172035,42062005 and 41572024)the China Geological Survey(Grant No.DD20221648)+1 种基金Yunnan Province Science and Technology Department(Grant No.202305AD160031,202401AT070012)the project entitled 1:50000 Regional Geological Survey of Dazhuang,Fabiao,Ditu,and Dianzhong Sheets in Yunnan Province(Grant No.D202207).
文摘The Jiangchuan Biota from the Jiucheng Member(Mb.)of the Dengying Formation(Fm.),discovered in Jiangchuan,eastern Yunnan,China,is marked by copious macrofossils at the apex of the Ediacaran strata.This fauna features benthic algae with varied holdfasts and other fossils of indeterminate taxonomic affinity and is compositionally unique compared to the Shibantan and Gaojiashan biotas of the Dengying Fm.and the Miaohe and Wenghui biotas of the Doushantuo Fm.,elsewhere in China.One novel benthic saccular macroalgal fossil,named here Houjiashania yuxiensis gen.and sp.nov.,from the Jiangchuan Biota is based on fossils that are sausage-shaped,elongate,tubular,ranging from 0.3 to 4 cm in length,and up to 0.8 cm in diameter.One terminus is blunt and rounded to an obtuse angle,the other is bent with a spread-out surface resembling a holdfast,suggesting a three-dimensional thallus.Thin,stipe-shaped outgrowths,likely vestiges of sessile saccular life forms,are prevalent in macroalgal fossils of analogous size and shape,as well as present brown algae Scytosiphonaceae,such as Colpomenia and Dactylosiphon.The new findings augment the diversity of benthic algae,such as those known from the Early Neoproterozoic Longfengshan Biota in North China.The benthic algal macrofossils in the Jiucheng Mb.add to knowledge of Late Ediacaran metaphyte diversification and offer more clues about the evolutionary positioning of primitive macroalgae.The co-occurrence of numerous planktonic and benthic multicellular algae and planktonic microbes might have facilitated ecologically the more extensive later Cambrian explosion evidenced by the Chengjiang Biota in Yunnan.
文摘Manadas Creek is an urban tributary of the Rio Grande that flows past a decommissioned antimony smelter and processing plant. This antimony plant is associated with heavy metal contamination in the creek and still poses a threat to the surrounding aquatic environment. Corbicula fluminea was used to determine bioaccumulation from the water column and sediments in Manadas Creek. The metals arsenic (As), antimony (Sb) and thallium (Tl) were analyzed in the water, sediments, gills, mantle, foot, digestive (DI) tract, gonads and shell of clams being monitored at eight sites between March and August 2013. Sediment, water, and dissected Corbicula fluminea samples from different sites in the Creek were acid-digested and analyzed by Inductively Coupled Plasma Optical Emission Spectroscopy. High levels of antimony (25.88 ug/L;75.96 mg/kg) and arsenic (8.26 ug/L;6.41 mg/kg) in the water and sediments were observed at the site downstream from the smelter. There were no detectable concentrations of arsenic, antimony, or thallium in the shell of C. fluminea. Arsenic and antimony were detected in the tissues of C. fluminea but thallium was not detected. Based on the results, the organotropism for arsenic is DI tract > gills > gonads > foot > mantle > shell and the organotropism for antimony is gills > DI tract > gonads > mantle > foot > shell. This study shows that the Asiatic clam (Corbicula fluminea) is a useful bio-monitor to provide data on the status of metal pollution in Manadas Creek, Laredo, Texas.
文摘Abundant and well-preserved remains of noncalcareous algae and soft-bodied metazoans were collected from Middle Cambrian Kaili biota in Taijiang county, Guizhou Province, China. These remains provide further evidence for the wide geographic distribution of many Burgess Shale taxa. Among the algae, 5 genera (including two new genera) and 5 species are described. They are Marpolia spissa Walcott, Acinocricus stichus Conway Morris and Robison, Udotealga erecta Yang, Eosargassum sawata Yang, and Rhizophyton zhaoyuanlongii Yang. Contrasting the macroalgal fossil assemblage in the Kaili biota with one in the Burgess Shale biota, it is clear that similarity of the Kaili biota and the Burgess Shale biota is reflected by the same content of not only the soft-bodied metazoans, but also the noncalcareous algae.
文摘The paper deals with a new species of megaalgal fossil-Enteromophites intestinalis sp. nov. found in Chenejiang Biota in the early Cambrian. A morphological comparison of the living Enteromorpha and fossil Enteromophites indicates that there probably is a close relationship between these two genera. Based on a study on the surroundings of living Enteromorpha, Enteromophites intestinalis sp. nov. might have lived in the environment of sea or salt water.
基金Financial support from the UK Natural Environment Research Council is gratefully acknowledged, and in particular: NE/I005803/1
文摘The extensive Late Mesozoic–Early Cenozoic sedimentary succession exposed within the James Ross Basin,Antarctica has huge potential to enhance paleobiological investigations into both the marine and terrestrial fossil records.In excess of 7 km in total thickness and spanning the Early Cretaceous(Aptian)–Late Eocene in age,it represents an invaluable high-latitude(~65°S)site for comparison with lower latitude,tropical ones in an essentially greenhouse world.The Early Cretaceous(Aptian–Albian)sequence is deep-water but there are indications of shallowing to inner shelf depths in both the Turonian and Coniacian stages.The first prolific shallow-water marine fauna occurs in the Santonian–Campanian Santa Marta Formation and this is followed by repeated occurrences through the later Campanian,Maastrichtian,Danian and Middle Eocene(Lutetian).In this study an attempt has been made to compare these Antarctic faunas directly with the well-known ones of the same age from the US Gulf Coast.Detailed comparisons made for three time slices,Late Maastrichtian,Danian and Middle Eocene,indicate that the Antarctic is characterised by both low taxonomic diversity and high levels of endemism.The James Ross Basin is providing important evidence to indicate that the highest southern latitudes have always been characterised by a distinctive temperate biota,even on a pre-glacial Earth.The roots of at least some elements of the modern Southern Ocean biota can be traced back to a Late Mesozoic–Early Cenozoic austral realm.
基金This research was supported in part by grants from the National Natural Sciences Foundation of China(40162002,40372023,40232020)from the Foundation of the Key and Basic Project of Science and Technology of Guizhou(Gui No.2002-309)+1 种基金from the Early and Special Projects of the Key and Basic Projects of the Ministry of Technology and Science of China(2002 CCC 02600)to Zhaofrom the U S.National Science Foundation(0106883,0229757)to Babcock.
文摘A Burgess Shale-type biota is, in part, characterized by a wide diversity of taxa and soft-part preservation. Each provides unique historical insights into early metazoan evolution. Among the more than 40 globally distributed biotas, the early Cambrian Chengjiang and Middle Cambrian Burgess-type biotas are the largest. The Kaili Biota, from the earliest Middle Cambrian of Guizhou, China, contains representatives of 110 metazoan genera belonging to 10 phyla. It contains many well-persevered soft-bodied specimens. This Chinese biota has become the third most taxonomically diverse Burgess Shale-type fauna. Because the Kaili Biota formed in an outer-shelf environment, its main faunal character is large numbers of eocrinoids and planktoic trilobites. The Kaili is younger than the Chengjiang Biota but older than the Canadian Burgess Shale Biota; it shares 30 genera with the Chengjiang and 38 genera with the Burgess Biota. The Kaili Biota displays a taphonomic window to the diversification and evolution of marine offshore organisms covering 5.13 million years between the Early and Middle Cambrian.
基金Financial support for this study was also provided by the National Natural Science Foundation of China(Project No.40302009)Peking University.
文摘After a slow recovery from the end-Permian extinction during the Early Triassic and rapid radiation in the Middle Triassic, evolution of organisms reached a new peak phase in the Late Triassic. The Guanling Biota from the Wayao Member （conodont Paragondolella polygnathiformis Zone）, Falang Formation, Xinpu, Guanling County, Guizhou Province, southwestern China corresponds to this peak that marks the full recovery from the end-Permian extinction of marine ecosystems. The biota is of high diversity, containing well preserved and completely articulated skeletons of vertebrates comprising marine reptiles, fishes, and invertebrates including crinoids, ammonites, bivalves, and other fossils, and is one of the best examples of marine ecosystem records in life history. The fossil marine reptiles and crinoids are most significant in this biota, especially the marine reptiles, which provide an important link between the Triassic Pacific and Tethys, and between Triassic basal forms and the Jurassic-Cretaceous marine top predators. The most remarkable fossils are the large completely articulated ichthyosaur skeletons up to and more than 10 m, and the first recorded thalattosaurs and placodonts in China. Following our review, of the 17 named reptilian taxa the eight listed here are considered to be valid： three ichthyosaurs （Qianichthyosaurus zhoui Li, 1999; Guizhouichthyosaurus tangae Cao and Luo in Yin et al., 2000, Guanlingsaurus liangae Yin in Yin et al., 2000）, three thalattosaurs （Anshunsaurus huangguoshuensis Liu, 1999, Xinpusaurus suni Yin in Yin et al., 2000, Xinpusaurus kohi Jiang et al., 2004）, and two placodonts （Sinocyamodus xinpuensis Li, 2000, Psephochelys polyosteoderma Li and Rieppel, 2002）. Mixosaurus guanlingensis Cao in Yin et al., 2000 might be a junior synonym of Qianichthyosaurus zhoui Li, 1999, and Cymbospondylus asiaticus Li and You, 2002 and Panjiangsaurus epicharis Chen and Cheng, 2003 might be junior synonyms of Guizhouichthyosaurus tangae Cao and Luo in Yin et al., 2000. It needs to re-describe the holotypes after a complete preparation for clarifying the taxonomic status of Typicusichthyosaurus tsaihuae Yu in Yin et al., 2000, Xinpusaurus bamaolinensis Cheng, 2003, Neosinosaurus hoangi （Zhou in Yin et al., 2000）, Wayaosaurus geei Zhou in Yin et al., 2000, Wayaosaurus bellus Zhou in Yin et al., 2000 and Placochelys ？ minutus Yin and Luo in Yin et al., 2000.
基金supported by the National Natural Science Foundation of China(Grant Nos.41425008,41890844,41720104002,41621003 and 41772002)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB26000000)+1 种基金the Overseas Expertise Introduction Centre for Discipline Innovation(111 project:D17013)the Postgraduate Creation Program of Northwest University(YZZ15001)
文摘Exceptionally preserved fossils,such as those from Cambrian Burgess Shale-type fossil-Lagerstatten are critical because of their unique contributions to knowledge of the phylogenetic radiation and palaeoecological expansion of metazoans during the Cambrian explosion.Critically,these deposits provide information that is usually unobtainable from shelly and skeletonized fossils alone.The Guanshan Biota(Cambrian Series 2,Stage 4)in the Yunnan Province of South China,has produced abundant and diverse,exquisitely preserved fossils that often retain soft tissues and organs.To date,most fossils from the Guanshan Biota have been collected from localities such as Gaoloufang and Gangtoucun,which have become inaccessible due to new urban expansions and constructions of residential buildings.Here we present the first report of soft bodied fossils from a new section at Kanfuqing,close to the Wulongqing village in Malong County,approximately 3 km east of the Wulongqing Formation stratotype section.Fossils retain soft morphology,and include brachiopods with delicate marginal setae,priapulids with well-preserved sclerites and vetulicolians with entire sections of body.In addition,this fauna includes rare occurrences of trilobites preserved with soft tissues replicated as pyrite pseudomorphs after weathering.This discovery represents an important palaeogeographical extension of soft-bodied fossils of the Guanshan fauna to the east of the Xiaojiang Fault(related to Tsinning tectonic movements ca.700 Ma).The fauna from the new Kanfuqing section is similar to that reported from the Wulongqing Formation west of the Xiaojiang Fault,and thus has significant implications for early Cambrian palaeogeography,faunal successions and palaeoenvironments of eastern Yunnan.
基金Supported by R01CA97946, R21DK57941, R01GM63270,R01 DK58587, and R01CA77955, and by the General Clinical Research Center core grant to New York University School of Medicine (NIH/NCRR M01 RR00096) from the National Institutes of Health, by the Medical Research Service of the Department of Veterans Affairs, and by the Ellison Medical Foundation
文摘AIM： To identify the bacterial flora in conditions such as Barrett＇s esophagus and reflux esophagitis to determine if they are similar to normal esophageal flora. METHODS： Using broad-range 16S rDNA PCR, esophageal biopsies were examined from 24 patients [9 with normal esophageal mucosa, 12 with gastroesophageal reflux disease （GERD）, and 3 with Barrett＇s esophagus]. Two separate broad-range PCR reactions were performed for each patient, and the resulting products were cloned. In one patient with Barrett＇s esophagus, 99 PCR clones were analyzed. RESULTS： Two separate clones were recovered from each patient （total = 48）, representing 24 different species, with 14 species homologous to known bacteria, 5 homologous to unidentified bacteria, and 5 were not homologous （〈97% identity） to any known bacterial 16S rDNA sequences. Seventeen species were found in the reflux esophagitis patients, 5 in the Barrett＇s esophagus patients, and 10 in normal esophagus patients. Further analysis concentrating on a single biopsy from an individual with Barrett＇s esophagus revealed the presence of 21 distinct bacterial species. Members of four phyla were represented, including Bacteroidetes, Firmicutes, Proteobacteria, and Actinobacteria. Microscopic examination of each biopsy demonstrated bacteria in intimate association with the distal esophageal epithelium, suggesting that the presence of these bacteria is not transitory. CONCLUSION： These findings provide evidence for a complex, residential bacterial population in esophageal reflux-related disorders. While much of this biota is present in the normal esophagus, more detailed comparisons may help identify potential disease associations.
