In the greater inland Jianghan Basin of South China,three salt depressions are lacking accurate geological times,of which Jiangling Depression is the largest.Evaporites are important records of paleoclimate,however,th...In the greater inland Jianghan Basin of South China,three salt depressions are lacking accurate geological times,of which Jiangling Depression is the largest.Evaporites are important records of paleoclimate,however,the geological ages of evaporates are very difficult to be determined because often evaporates have scare macrofossils and microfossils.Nonmarine Cretaceous to Tertiary halite deposits interbedded with mudstones are widely distributed in China.Paleocene-Eocene Thermal Maximum had very high temperatures and attracted strong interests of geologists because these times can be compared with future climate change because of global warming.However,previous studies focused on marine sediments found that during the Paleocene-Early Eocene,massive evaporate deposits formed in Jiangling depression of the Jianghan Basin.In this paper,the authors show that the Shashi Formation halite deposits formed in the Paleocene according to palynology.Most of these palynology fossils are arid types,so the massive evaporites in the Jiangling depression could be closely related to the hot Paleocene climate.High temperatures during the Paleocene contributed to the formation of the massive evaporates in the Jiangling Depression,until sylvite was the result.展开更多
Studying the climatic and environmental changes on different time scales in inland arid regions of Asia can greatly im‐prove our understanding of climatic influences for the Qinghai-Tibet Plateau in the context of gl...Studying the climatic and environmental changes on different time scales in inland arid regions of Asia can greatly im‐prove our understanding of climatic influences for the Qinghai-Tibet Plateau in the context of global change. Pollen, as a remnant of seed plants, is sensitive to environmental factors including precipitation, temperature and altitude, and is a clas‐sic proxy in environmental reconstruction. In the last two decades, great progress in the application of palynology to in‐land areas of Asia has highlighted the role of palynology in paleoclimatic and paleoenvironmental research. The main progress is as follows. (1) On the tectonic time scale of the late Cenozoic, the palaeoclimatological sequence has been es‐tablished on the basis of pollen percentage, concentration and taxon. Pollen data have revealed a continuous enhancement of drought in the inland arid region of Asia, in contrast to evidence acquired based on other proxies. (2) In the late Quater‐nary, an increase in herbaceous plants further supports the intensification of drought associated with global cooling. In more detail, the palynological record shows a glacial-interglacial pattern consistent with changes in global ice volume. (3) The Holocene pollen record has been established at a high resolution and across a wide range of inland areas. In general, it presents an arid grassland environment in the early Holocene, followed by the development of woody plants in the mid- to late-Holocene climate optimum. This pattern is related to moisture changes in areas dominated by the westerlies. There are also significant regional differences in the pattern and amplitude of vegetation response to the Holocene environment. (4) Modern pollen studies based on vegetation surveys, meteorological data and statistics show that topsoil palynology can better reflect regional vegetation types (e. g., grassland, meadow, desert). Drier climates yield higher pollen contents of drought-tolerant plants such as Chenopodioideae, Ephedra, and Nitriaria, while contents of Artemisia and Poaceae are greater under humid climates. Besides these achievements, problems remain in palynological research: for example, pol‐len extraction, identification, interpretation, and quantitative reconstruction. In the future, we encourage strengthened inter‐disciplinary cooperation to improve experimental methods and innovation. Firstly, we should strengthen palynological classification and improve the skill of identification;secondly, laboratory experiments are needed to better constrain pol‐len transport dynamics in water and air;thirdly, more rigorous mathematical principles will improve the reliability of re‐constructions and deepen the knowledge of plant geography;and finally, new areas and methods in palynology should be explored, for example DNA, UV-B and isotopic analysis. It is expected that palynology will continue to develop, and we hope it will continue to play an important role in the study of past climatic and environmental changes.展开更多
Globally, the Paleogene period experienced several events marking the Paleocene-Eocene transition which is especially to one of the hottest periods that the Earth has ever known (Paleocene-Eocene Thermal Maximum, PETM...Globally, the Paleogene period experienced several events marking the Paleocene-Eocene transition which is especially to one of the hottest periods that the Earth has ever known (Paleocene-Eocene Thermal Maximum, PETM), followed by the biological crisis that affected benthic foraminifera. The Bekrit Syncline, subject of this study, shows three Formations of range from the Cretaceous to the Eocene ages (the El Koubbat, Irbzer and Bekrit-Timahdite Formations). Sedimentological, palynological and geochemical analyses of collected samples, in the Bekrit syncline, were studied to determine the paleogeographic and paleoenvironmental conditions of the Middle Atlas. The carbonate rocks were analyzed by microscopic study and geochemical analysis by X-ray Fluorescence (XF) and Inductively Coupled Plasma Spectrometry (ICP). The results obtained highlight the sedimentary events that took place during the Paleogene. Thus, the Maastrichtian is characterized by a closed euxinic marine environment shared by a more open and oxidizing environment. On the other hand, the Paleocene was a restricted marine environment with evaporitic sedimentation, while the Eocene sees the installation of a carbonate platform with a bioclastic Shoal.展开更多
Quaternary palynology in the Tibetan Plateau(TP)was initiated in the 1960s to meet the needs of economic development in western China.Pollen analysis was conducted for the first time on a 200-m long core of Quaternary...Quaternary palynology in the Tibetan Plateau(TP)was initiated in the 1960s to meet the needs of economic development in western China.Pollen analysis was conducted for the first time on a 200-m long core of Quaternary lacustrine sediments taken from the main body of the TP in order to study pollen assemblages as well as vegetation and climate changes of glacial(cold)/interglacial(warm)periods.Pollen analysis of alpine snow and ice began at the first scientific expedition to the TP in the 1970s.After the 1980s,a series of international collaborative programs were carried out under Sino-French,Sino-German,Sino-Australian,and Sino-American cooperation,marking the integration of Chinese Quaternary palynology society with the international community.New methods for Quaternary palynology were gradually promoted and applied,changing the vegetational and climatic interpretation of Quaternary palynology from qualitative to quantitative.Since the 1990s,many palynologists have carried out extensive Quaternary palynological studies on fossil pollen sites of more than 60 lakes/sections and alpine glaciers in the TP to discuss the spatiotemporal vegetation changes and climatic and environmental evolution of the TP since the Pleistocene.Over the past half-century,Quaternary palynology in the TP has contributed to the establishment of the Chinese Quaternary pollen database and the study of vegetation and climate evolution since the Last Glacial Maximum(LGM)in the TP.Currently available pollen records revealed the spatial and temporal distribution of vegetation in the TP since the LGM,exhibiting expansions and shrinkages of forest,meadow,grassland and desert in different periods such as the LGM,the last deglaciation,and Holocene optimum period.The paleomonsoon reflected by paleovegetation since the LGM has undergone the changes of weak-strengthening-strong-weakening but still active-shrinking,which is mainly affected by solar insolation.展开更多
Both lithological and palynological analyses were employed to decipher sedimentary stacking patterns and to date the sediments within the interval 50—325 m in Kemar-1 well,Bornu Basin,northeastern Nigeria.Eight diffe...Both lithological and palynological analyses were employed to decipher sedimentary stacking patterns and to date the sediments within the interval 50—325 m in Kemar-1 well,Bornu Basin,northeastern Nigeria.Eight different lithofacies units deposited in various environments were recognized.They are:(1) the grayish sandy claystone,rich in organic matter and associated with lignite,deposited in a continental to lacustrine environment;(2) the micaceous claystone,rich in muscovite flakes and organic matter,deposited in a lacustrine environment;(3) the lithified claystone which intercalates the dark gray shale,and deposited in a marine setting;(4) the shale;(5) the micaceous sandstone,which is characterized by presence of muscovite,silty to granular grain sizes,well sorted and deposited in a meandering setting;(6) the poorly-sorted sandstone.It is poorly sorted,poorly-graded,and coarse-grained,with erosive surfaces to underlying facies,and deposited in a fluvial environment;(7) the heterolithic clayey sandstone,poorly graded,grayish,with a degree of organic richness,suggesting an anoxic lacustrine environment;and(8) the grayish claystone which is nonlithic and rarely ferruginized marking the Upper Miocene/Eocene boundary.One main palynological zone,i.e.,the Echitricolporites spinosus assemblage zone,has been established.The base of the studied section at 385 m is characterized by the last up-hole occurrence of Grimsdalea magnaclavata suggestive of Eocene boundary while the overlying sediments are characterized by Late Miocene marker species such as E.spinosus,Elaeis guineensis,Anthocerus sp.,Nymphaea lotus,and Retistepho.nocolpites gracilis.The Chad Formation is dated as Late Miocene age unconformably overlying the Eocene Kerri-Kerri Formation which indicated that the Chad Formation was probably deposited during an alternation of lacustrine and continental settings,due to climatic change.展开更多
Quaternary palynology plays a pivotal role in investigating global climate change and various other research fields,serving as an essential tool for the quantitative analysis of paleoenvironment changes.However,due to...Quaternary palynology plays a pivotal role in investigating global climate change and various other research fields,serving as an essential tool for the quantitative analysis of paleoenvironment changes.However,due to the vast diversity of terrestrial ecosystems and intricate interactions between vegetation,climate,and human activities,further advancements are required in the following aspects within this discipline.(1)The accuracy of classification in pollen morphology and fossil pollen identification needs improvement,particularly at the species level.This represents a significant challenge in present Quaternary palynology.Computer-aided intelligent recognition holds promise as a solution for species identification based on more detail pollen morphology.(2)Most pollen-based vegetation and climate reconstructions overlook the significance of bare ground.Neglecting bare ground can lead to substantial inaccuracies when quantitatively reconstructing past vegetation and climate.(3)While pollen records provide reliable information on paleoclimate changes,current quantitative climate reconstruction models heavily rely on modern pollen datasets derived from present-day vegetation disturbed more or less by human activities.This introduces bias and uncertainties into paleoclimate reconstruction.(4)Although pollen can serve as an indicator of human activities,accurately quantifying the intensity of human influence remains challenging.Improving accurate identification of crop pollen,reconstructing reliable land cover/use data,and integrating multidisciplinary data may enhance the identification and quantification of signals related to human activity in pollen records.展开更多
The Permian-Triassic(P/T)transition is marked by the most severe mass-extinction event of the Phanerozoic.Although much is known about this event in the marine realm,there are many open questions regarding what happen...The Permian-Triassic(P/T)transition is marked by the most severe mass-extinction event of the Phanerozoic.Although much is known about this event in the marine realm,there are many open questions regarding what happened during this period to many continental biota.In the case of plants,a drastic mass-extinction event has even been negated by some authors.To add about the knowledge on continental biota in India during this crucial time period,the present study analysed the palynology,palynofacies,organic geochemistry(biomarkers),stable isotopes,and charcoal within the subsurface Gondwana deposits of the Kamthi Formation(late Permian-early Triassic)from core TTB-7 from the Tribida block,located in the Talcher Coalfield of the Mahanadi Basin,India.The primary objectives are to validate the age of the strata,ascertain the palaeodepositional setting of the palaeomire,and propose palaeobotanical evidence regarding the occurrence of wildfires within this stratigraphic succession and changes in floral content across the P/T transition.The palynological study proposes two palynoassemblage zones,Densipollenites magnicorpus and Klausipollenites schaubergeri,suggesting a latest Permian(Lopingian)and early Triassic(Induan?)age for the studied succession,respectively.The age is also inferred based on correlation with coeval assemblages from India and other Gondwana continents.The palynoassemblages reveal the dominance of Glossopteridales and Coniferales along with Filicales,Lycopsidales,Equisetales,Cordaitales and Peltaspermales.The relatively higher values of the carbon preference index and terrigenous/aquatic ratio also suggest higher plant input.However,a bimodal n-alkane distribution pattern suggests the contribution of terrigenous and microbial sources.Although the occurrences of long-chain alkanes indicate input of higher plants,the low Pwax values(<0.26)suggest relatively less contribution.The Paqvalues(≅1)and amorphous organic matter(av.33.24%)suggest a significant macrophyte input in the studied samples,pointing to the occurrence of moderate aquatic conditions in the basin.Furthermore,the distribution of hopanoids and the content of degraded organic matter(av.29.96%)reflect the bacterial degradation of organic matter.Also,the δ^(13)C values of the studied section varied from−31.2‰to−21.8‰.A large carbon isotopic offset of 9.4‰across the P/T transition,Pr/Ph ratio(0.3–1.3)and shift in the distribution pattern of palynofacies components is indicating a significant change in climatic conditions.Moreover,the presence of macroscopic charcoal fragments of gymnospermous affinity with pre-charring colonization by fungi provides evidence for wildfire occurring during the Lopingian(Late Permian)in this basin.展开更多
This study explores the application of YOLOv10,a cutting-edge object detection framework,to automate the identification and classification of Batioladinium longicornutum.Utilizing a dataset of 137 annotated images,we ...This study explores the application of YOLOv10,a cutting-edge object detection framework,to automate the identification and classification of Batioladinium longicornutum.Utilizing a dataset of 137 annotated images,we trained and validated the model to distinguish B.longicornutum from other species with a mean Average Precision(mAP@0.5)of 62.0%.The methodology incorporated robust data augmentation techniques and evaluation metrics,including precision-recall analysis,confusion matrices,and cross-validation.YOLOv10’s architecture facilitated accurate feature extraction and efficient classification,even with a relatively small dataset.While this study focuses on species-level identification,future work will extend to morphological and preservation state classifications,offering broader applications in automated palynology.These findings demonstrate the potential of YOLOv10 to revolutionize taxonomic workflows and enhance the efficiency of paleontological research.展开更多
The Toarcian Oceanic Anoxic Event(T-OAE,∼183 Ma)is marked in the sedimentary record by a sharp negative carbon isotope excursion,thought to be causally linked to the emplacement of the Karoo-Ferrar Large Igneous Prov...The Toarcian Oceanic Anoxic Event(T-OAE,∼183 Ma)is marked in the sedimentary record by a sharp negative carbon isotope excursion,thought to be causally linked to the emplacement of the Karoo-Ferrar Large Igneous Province and the associated release of^(12)C-enriched carbon.The T-OAE coincided with global climate and environmental changes,as well as biotic events,indicating substantial modifications in ecosystems.Recent studies have focused on the evidence of geological responses to the T-OAE in Early Jurassic terrestrial basins in China,particularly the Sichuan Basin.Nevertheless,debate remains over the identification of this event,owing to inadequate age-constraints of many sections,and a lack of robust correlations of the carbon isotope records.Moreover,the long-term evolution of the terrestrial carbon isotope record through the Early Jurassic,and its correlation to marine records,is still not firmly established.In this paper,we present new carbon isotope analyses of carbonate(δ^(13)C_(carb))from lacustrine carbonates and terrestrial organic matter(δ^(13)C_(org))from bulk rocks within the Ma’anshan and Da’anzhai members of the Ziliujing Formation from the Dacao‘D’(DCD)section in the eastern Sichuan Basin.Palynological-palynofacies analysis reveals a predominance of Classopollis pollen together with marker taxa such as Ischyosporites variegatus,Contignisporites problematicus,in the palynological assemblage,indicating a Pliensbachian–Toarcian age.A negative carbon isotope excursion(NCIE)is recorded in the organic carbon isotope data at the topmost part of the Pliensbachian Ma’anshan Member,which can be correlated to the Pliensbachian–Toarcian Boundary Event.This is followed,in the Toarcian Da’anzhai Member,by a major NCIE recorded in both organic matter and carbonate carbon isotope data which can be correlated to the T-OAE NCIE.A long-term carbon isotope record spanning the Sinemurian to Toarcian in Sichuan terrestrial sediments is also been reconstructed and its correlation with coeval marine records is proposed.A broader review of δ^(13)C data from Chinese terrestrial basins spanning the Pliensbachian–Toarcian highlights a distinct^(13)C-depleted signature in the Sichuan Basin compared to basins at higher latitudes.Changes in latitudinal gradients and organic matters in the lake sediments were likely important factors influencing the amplitudes of the T-OAE NCIE and the carbon isotope values in terrestrial sedimentary records.展开更多
Fossil bamboo leaves and pollen from Upper Miocene deposits of the Shengxian Formation in Tiantai and Ninghai counties, eastern Zhejiang, China represent a rare record in Asia. The distinctive pseudopetiole and parall...Fossil bamboo leaves and pollen from Upper Miocene deposits of the Shengxian Formation in Tiantai and Ninghai counties, eastern Zhejiang, China represent a rare record in Asia. The distinctive pseudopetiole and parallel venation of the leaf blades and the clearly thickened annulus of the pollen aperture place them in the subfamily Bambusoideae. Morphological analysis supports the determination of these fossil leaves as belonging to the genus Bambusium and two new species are described. Bambusium latipseudopetiolus Q.J. Wang et B.N. Sun sp. nov. has a distinctly wide pseudopetiole of 0.23 cm in width and 0.40 cm in length, several vascular bundles on parallel veins, and 5-8 lateral veins on both sides of the midrib. Bambusium longipseudopetiolus Q.J. Wang et B.N. Sun sp. nov. has a distinctly long pseudopetiole of 0.60 cm in length and 0.10 cm in width, several vascular bundles on the pseudopetiole, and 6 lateral veins on both sides of the midrib. Pollen grains from the same layer provide additional evidence of bamboos. They are characterized by 32.0-51.0 μm in diameter, a round pore 3.0-4.0 μm in diameter with a broad thickened annulus 2.5-3.5 μm around, and several conspicuous secondary folds on the exine surface. The morphological analysis leads to their assignment to Graminidites bambusoides Stuchlik. These fossils are important for the study of bamboo phytogeography in China. They demonstrate that there were bamboos growing in southeastern China during the Late Miocene and that bamboos in Zhejiang begin to diversify no later than the Late Miocene. In combination with bamboo fossils from other places, it seems that bamboos had a wide distribution across southern China during the Miocene, ranging from southwestern Yun＇nan to southeastern Zhejiang.展开更多
The Triassic-Jurassic （Tr-J） boundary marks a major extinction event, which （～200 Ma）resulted in global extinctions of fauna and flora both in the marine and terrestrial realms. There prevail great challenges in ...The Triassic-Jurassic （Tr-J） boundary marks a major extinction event, which （～200 Ma）resulted in global extinctions of fauna and flora both in the marine and terrestrial realms. There prevail great challenges in determining the exact location of the terrestrial Tr-J boundary, because of endemism of taxa and the scarcity of fossils in terrestrial settings leading to difficulties in linking marine and terrestrial sedimentary successions. Investigation based on palynology and bivalves has been carried out over a 1113 m thick section, which is subdivided into 132 beds, along the Haojiagou valley on the southern margin of the Junggar Basin of the northern Xinjiang, northwestern China. The terrestrial Lower Jurassic is conformably resting on the Upper Triassic strata. The Upper Triassic covers the Huangshanjie Formation overlaid by the Haojiagou Formation, while the Lower Jurassic comprises the Badaowan Formation followed by the Sangonghe Formation. Fifty six pollen and spore taxa and one algal taxon were identified from the sediments. Based on the key-species and abundance of spores and pollen, three zones were erected： the Late Triassic （Rhaetian） Aratrisporites-Alisporites Assemblage, the Early Jurassic （Hettangian） Perinopollenites-Pinuspollenites Assemblage, and the Sinemurian Perinopollenites-Cycadopites Assemblage. The Tr-J boundary is placed between bed 44and 45 coincident with the boundary between the Haojiagou and Badaowan formations. Beds with Ferganoconcha （？）, Unio-Ferganoconcha and Waagenoperna-Yananoconcha bivalve assemblages are recognized. The Ferganoconcha （？） bed is limited to the upper Haojiagou Formation,Unio- Ferganoconcha and Waagenoperna- Yananoconcha assemblages are present in the middle and upper members of the Badaowan Formation. The sedimentary succession is interpreted as terrestrial with two mainly lake deposit intervals within Haojiagou and Badaowan formations, yielding fresh water algae and bivalves. However, the presence of brackish water algae Tasmanites and the marine-littoral facies bivalve Waagenoperna from the Badaowan Formation indicate that the Junggar Basin was influenced by sea water caused by transgressions from the northern Tethys, during the Sinemurian.展开更多
Because of the unique geographical location and important ecological effect of the Qinling Mountains, reconstruction of its vegetation and climate needs comprehensive research. We need to consider a multiple-proxy app...Because of the unique geographical location and important ecological effect of the Qinling Mountains, reconstruction of its vegetation and climate needs comprehensive research. We need to consider a multiple-proxy approach to gain more information on recovering the paleovegetation and climate in the Qinling Mountains. Black carbon （BC） is produced by the incomplete combustion of vegetation and fossil fuels, and is a good proxy, recording paleoenvironmental information. However, in the Qinling Mountains, what are the characteristics of the BC, and whether BC stable carbon isotope （δ^13CBc） can be used as a new proxy to study ancient vegetation, still need further study. In order to establish a sound basis for studying paleoenvironmental by BC proxy in the Qinling Mountains, we carried out systematic and detailed study on modern process of BC on the northern slope of the mountains. We analyzed stable carbon isotopes and carbon concentration of organic carbon （% SOC, δ^13Csoc） and BC （%BC, δ^13CBc）, and identified the pollen assemblages from systematically sampled surface soil. The results show that the calculated ratio of C4 plants in the vegetation （%C4） based on the δ13Csoc data reflects a similar distribution of C4 plants in the surface vegetation and the pollen assemblage. The δ^13Cac values have a strong positive correlation with δ13Csoc values, and their difference （△13CSOC-BC） is in the low range. These data indicate that δ^13CBC and δ^13CSOC have very similar characteristics. Surface soil δ13BC values can indicate surface vegetation as effectively as δ^13Csoc values, and the δ^13CBC proxy can be used effectively in paleovegetational research in the northern slope of Qinling Mountains.展开更多
An amber-bearing lignitic layer of sandy clay from the Lower Cretaceous of Central Lebanon （Mderej-Hammana）yielded a well-preserved,moderately variegated palynoflora,which origin is mixed between land plants and mar...An amber-bearing lignitic layer of sandy clay from the Lower Cretaceous of Central Lebanon （Mderej-Hammana）yielded a well-preserved,moderately variegated palynoflora,which origin is mixed between land plants and marine microflora.Its detailed analysis led to fulfill its inventory,to propose a paleoenvironmental reconstruction,and to draw the paleoclimate which prevailed over the region：an estuarian area under a rather humid,temperate climate;a variety of ferns grew near the shore-side and in the inward land.A tiny piece of amber containing angiospermous pollen grains of stratigraphical interest allows a precise dating.The marine microflora,poorly diversified,includes chitinous foraminifer linings and dinoflagellate cysts,among which Early Aptian guide taxa are present;their occurrence slightly narrows the stratigraphical range indicated by some palynological taxa which are related to land plants.展开更多
Two Upper Devonian to Lower Carboniferous sections,namely the Bulongguoer and Haer(Gennaren area)in the Junggar Basin,Central Asian Orogenic Belt,in northwestern China were examined with regard to ichnology and palyno...Two Upper Devonian to Lower Carboniferous sections,namely the Bulongguoer and Haer(Gennaren area)in the Junggar Basin,Central Asian Orogenic Belt,in northwestern China were examined with regard to ichnology and palynology.The deposits of the Hongguleleng Formation and Namu Member of the Heishantou Formation,respectively,are mostly unbioturbated or poorly bioturbated,with poorly diversified trace fossils,which indicate unfavourable conditions for the burrowing benthic community during the Late Devonian and Early Carboniferous.The main factor governing the growth of the bioturbating population was the rapid sedimentation of fine-grained,volcanic material documented as tempestites,which buried the benthic fauna.In the Bulongguoer section,the presence of miospores Teichertospora torquata and Grandispora gracilis enabled identification of the broad Teichertospora torquata–Grandispora gracilis Miospore Zone from the transitional Frasnian/Famennian interval.More accurate identification of palynostratigraphical levels(DE and CZ Miospore zones)is only tentative.On the basis of palynofacies analysis,samples from the lower Bulongguoer section indicate deposition in more proximal conditions,whereas samples from the top of the section indicate deposition in a more distal environment.In the Haer section,only a general biostratigraphic indication for the Tournaisian was possible,owing to poor preservation of organic matter.展开更多
The lithological and geochemical composition and conditions of formation of the coal-bearing deposits of the Kizel Coal Basin in the Perm region of the Urals(central Russia)are described using the two most representat...The lithological and geochemical composition and conditions of formation of the coal-bearing deposits of the Kizel Coal Basin in the Perm region of the Urals(central Russia)are described using the two most representative sections,Gubakha-Stary Most and Krestovaya Mountain,based on a detailed“layer-by-layer”technique.Brief characteristics of the Lower Carboniferous paleosols from fossil paleosol(FPS-)profiles of the studied region are given.Special attention is paid to the parent vegetation of the coal-forming processes,based on an analysis of both plant macrofossils and palynoflora.The peat accumulation in conditions of permanent incoming of clastic material from the Paleo-Urals to the Kizel Basin was probably effective only in more or less stable environments,when the accumulated organic matter produced by plant mortmass was not dissolved by clastic particles.Thus,the conditions of coal-forming are reconstructed as a forest swamp,where the main dominants are represented by lycopodiopsids of the order Lepidodendrales,predominantly Lepidodendron veltheimii.These plants in particular were the source of the initial organic matter for the peat(and later coal)of the Kizel Coal Basin.展开更多
Since the time of the rainy Holocene, there have been periods of consecutive rain and drought on Egypt. Study of carbon 14 in the long-lived coniferous tree rings could see activity in the sun （spots and solar flares...Since the time of the rainy Holocene, there have been periods of consecutive rain and drought on Egypt. Study of carbon 14 in the long-lived coniferous tree rings could see activity in the sun （spots and solar flares） during eleven years cycle, as well as knowledge of possible flooding of the Nile and the periods of increase and decrease of the extent necessary to meet the soil around Lake Qarun in Fayoum-Egypt. From historical records in ancient Egypt and Muslim countries, the possible link between periods of the disappearance of sunspots on the solar disc for several years and is known to inch lower level and role of the minimum level of Mandour creeping ice on Southern Europe to the Mediterranean Sea, and the offset of the drought in North Africa and the Sahel region of Africa during the last thousand years. Analyzed pollen fossils of the overlapped layers of soil in two areas of the Delta were Avaris in Sharkiya Province and Mendes in Dakahliya Province. The study pointed out that there are differences due to environmental conditions, demonstrated by the analysis of soil pH, increased electrical connectivity also, the evidence of sulfates and chlorides indicate high salinity of Mendes and Avaris. Also the analysis of fossil pollen of successive layers of soil for both regions resulted in findings of fossil pollen of the species Chenopodiaceae by 51.2%, in Mendes, while, 7% in the Avaris. This is strong evidence of the existence conditions of salt in Mendes than Avaris archaeological sites.展开更多
The Permian is one of the most important periods during which the vegetative earth witnessed the transition from icehouse to greenhouse climate and the global environment changes.Organisms on the planet encountered gr...The Permian is one of the most important periods during which the vegetative earth witnessed the transition from icehouse to greenhouse climate and the global environment changes.Organisms on the planet encountered great challenge and the demise of swamp caused the extinction of arborescent lycopods and the rising of Mesophytic plants accomplished the floral transition from the Paleophytic to Mesophytic vegetation.In order to depict the climatic changes and floral succession in the middle and high latitudes of the North Hemisphere,palynological investigation was engaged,and 40 samples collected from the uppermost of Taerlang Formation,Hongyanchi Formation and Quanzijie Formation in the Tianshan Town,Turpan-Hami Basin,eastern Xinjiang,China.The result shows that the palynoflora in the studied area is composed of 50 species of 33 genera,dominated by disaccites and striatiti gymnosperm pollen,and characterized by diverse Protohaploxypinus,Hamia-pollenites,Alisporites and Klausipollenites.It is quite similar to those Middle and Late Permian palynological assemblages reported in the Dalongkou section and other localities in southern margin of Junggar Basin,and aged at Middle and Late Permian.The diversity of typical Angara and sub-Angara pollen,such as Falcisporites,Alisporites,Protohaploxypinus,Vittatina,Lunatisporites,Hamiapollenites,etc.indicates that the studied palynoflora belonged to the sub-Angara phytoprovince,while the presence of Lueckisporites virkkiae implied Euramerica pollen intruded northward sometimes.The paleoclimate of the studied area might be warm and humid with fluctuated dry seasons during the late Guadalupian and early Lopingian time.展开更多
A well-preserved Late Cretaceous-Paleogene palynological flora from the middle member of the Tsagajan Formation and the upper member of the Tsagajan Formation including the Kivda Beds is reported for the first time fr...A well-preserved Late Cretaceous-Paleogene palynological flora from the middle member of the Tsagajan Formation and the upper member of the Tsagajan Formation including the Kivda Beds is reported for the first time from the Arkhara-Boguchan brown coal mine, southeastern part of the Zeya-Bureya Basin. Four palynocomplexes were established for the Cretaceous-Tertiary transition. The climate and phytocoenoses were also analyzed,based on the detailed palynological data. The results are coincident with those of mega-flora studied by Akhmetiev et al. (2002).展开更多
基金This research was supported by National Natural Science Foundation of China(41502089,41173051,41473039)Major State Basic Research Development Program(973 Program,2011CB403007)+1 种基金Central Welfare Basic Scientific Research Business Expenses(YK1603,K1415,K1703)China Geological Survey programs(DD20190816,DD20190817,DD20190606).
文摘In the greater inland Jianghan Basin of South China,three salt depressions are lacking accurate geological times,of which Jiangling Depression is the largest.Evaporites are important records of paleoclimate,however,the geological ages of evaporates are very difficult to be determined because often evaporates have scare macrofossils and microfossils.Nonmarine Cretaceous to Tertiary halite deposits interbedded with mudstones are widely distributed in China.Paleocene-Eocene Thermal Maximum had very high temperatures and attracted strong interests of geologists because these times can be compared with future climate change because of global warming.However,previous studies focused on marine sediments found that during the Paleocene-Early Eocene,massive evaporate deposits formed in Jiangling depression of the Jianghan Basin.In this paper,the authors show that the Shashi Formation halite deposits formed in the Paleocene according to palynology.Most of these palynology fossils are arid types,so the massive evaporites in the Jiangling depression could be closely related to the hot Paleocene climate.High temperatures during the Paleocene contributed to the formation of the massive evaporates in the Jiangling Depression,until sylvite was the result.
基金the NSFC(41772181,41807440 and 41888101)the Strategic Priority Research Program of CAS(No.XDA20070200)+4 种基金Young Top Talents Project of the"Ten Thousand Youth Program"of the Organization Department of the Central Committee of the CPCYouth Innovation Promotion Association,CAS(2014383)"Light of West China"Program,CASand the NSF of Gansu Province(18JR3RA395)We thank Miao's group members and anonymous referees for discussions and their constructive suggestions。
文摘Studying the climatic and environmental changes on different time scales in inland arid regions of Asia can greatly im‐prove our understanding of climatic influences for the Qinghai-Tibet Plateau in the context of global change. Pollen, as a remnant of seed plants, is sensitive to environmental factors including precipitation, temperature and altitude, and is a clas‐sic proxy in environmental reconstruction. In the last two decades, great progress in the application of palynology to in‐land areas of Asia has highlighted the role of palynology in paleoclimatic and paleoenvironmental research. The main progress is as follows. (1) On the tectonic time scale of the late Cenozoic, the palaeoclimatological sequence has been es‐tablished on the basis of pollen percentage, concentration and taxon. Pollen data have revealed a continuous enhancement of drought in the inland arid region of Asia, in contrast to evidence acquired based on other proxies. (2) In the late Quater‐nary, an increase in herbaceous plants further supports the intensification of drought associated with global cooling. In more detail, the palynological record shows a glacial-interglacial pattern consistent with changes in global ice volume. (3) The Holocene pollen record has been established at a high resolution and across a wide range of inland areas. In general, it presents an arid grassland environment in the early Holocene, followed by the development of woody plants in the mid- to late-Holocene climate optimum. This pattern is related to moisture changes in areas dominated by the westerlies. There are also significant regional differences in the pattern and amplitude of vegetation response to the Holocene environment. (4) Modern pollen studies based on vegetation surveys, meteorological data and statistics show that topsoil palynology can better reflect regional vegetation types (e. g., grassland, meadow, desert). Drier climates yield higher pollen contents of drought-tolerant plants such as Chenopodioideae, Ephedra, and Nitriaria, while contents of Artemisia and Poaceae are greater under humid climates. Besides these achievements, problems remain in palynological research: for example, pol‐len extraction, identification, interpretation, and quantitative reconstruction. In the future, we encourage strengthened inter‐disciplinary cooperation to improve experimental methods and innovation. Firstly, we should strengthen palynological classification and improve the skill of identification;secondly, laboratory experiments are needed to better constrain pol‐len transport dynamics in water and air;thirdly, more rigorous mathematical principles will improve the reliability of re‐constructions and deepen the knowledge of plant geography;and finally, new areas and methods in palynology should be explored, for example DNA, UV-B and isotopic analysis. It is expected that palynology will continue to develop, and we hope it will continue to play an important role in the study of past climatic and environmental changes.
文摘Globally, the Paleogene period experienced several events marking the Paleocene-Eocene transition which is especially to one of the hottest periods that the Earth has ever known (Paleocene-Eocene Thermal Maximum, PETM), followed by the biological crisis that affected benthic foraminifera. The Bekrit Syncline, subject of this study, shows three Formations of range from the Cretaceous to the Eocene ages (the El Koubbat, Irbzer and Bekrit-Timahdite Formations). Sedimentological, palynological and geochemical analyses of collected samples, in the Bekrit syncline, were studied to determine the paleogeographic and paleoenvironmental conditions of the Middle Atlas. The carbonate rocks were analyzed by microscopic study and geochemical analysis by X-ray Fluorescence (XF) and Inductively Coupled Plasma Spectrometry (ICP). The results obtained highlight the sedimentary events that took place during the Paleogene. Thus, the Maastrichtian is characterized by a closed euxinic marine environment shared by a more open and oxidizing environment. On the other hand, the Paleocene was a restricted marine environment with evaporitic sedimentation, while the Eocene sees the installation of a carbonate platform with a bioclastic Shoal.
基金This work was supported by Special Project for Basic Research of Yunnan Province-Key Project(Grant No.202101AS070006)the Yunnan Project for the Introduction of Advanced Talents(Grant No.2013HA024)+1 种基金the National Natural Science Foundation of China(Grant Nos.41372191 and 42067061)the Key Project of Education Department of Hunan Province(Grant No.20A400).
文摘Quaternary palynology in the Tibetan Plateau(TP)was initiated in the 1960s to meet the needs of economic development in western China.Pollen analysis was conducted for the first time on a 200-m long core of Quaternary lacustrine sediments taken from the main body of the TP in order to study pollen assemblages as well as vegetation and climate changes of glacial(cold)/interglacial(warm)periods.Pollen analysis of alpine snow and ice began at the first scientific expedition to the TP in the 1970s.After the 1980s,a series of international collaborative programs were carried out under Sino-French,Sino-German,Sino-Australian,and Sino-American cooperation,marking the integration of Chinese Quaternary palynology society with the international community.New methods for Quaternary palynology were gradually promoted and applied,changing the vegetational and climatic interpretation of Quaternary palynology from qualitative to quantitative.Since the 1990s,many palynologists have carried out extensive Quaternary palynological studies on fossil pollen sites of more than 60 lakes/sections and alpine glaciers in the TP to discuss the spatiotemporal vegetation changes and climatic and environmental evolution of the TP since the Pleistocene.Over the past half-century,Quaternary palynology in the TP has contributed to the establishment of the Chinese Quaternary pollen database and the study of vegetation and climate evolution since the Last Glacial Maximum(LGM)in the TP.Currently available pollen records revealed the spatial and temporal distribution of vegetation in the TP since the LGM,exhibiting expansions and shrinkages of forest,meadow,grassland and desert in different periods such as the LGM,the last deglaciation,and Holocene optimum period.The paleomonsoon reflected by paleovegetation since the LGM has undergone the changes of weak-strengthening-strong-weakening but still active-shrinking,which is mainly affected by solar insolation.
文摘Both lithological and palynological analyses were employed to decipher sedimentary stacking patterns and to date the sediments within the interval 50—325 m in Kemar-1 well,Bornu Basin,northeastern Nigeria.Eight different lithofacies units deposited in various environments were recognized.They are:(1) the grayish sandy claystone,rich in organic matter and associated with lignite,deposited in a continental to lacustrine environment;(2) the micaceous claystone,rich in muscovite flakes and organic matter,deposited in a lacustrine environment;(3) the lithified claystone which intercalates the dark gray shale,and deposited in a marine setting;(4) the shale;(5) the micaceous sandstone,which is characterized by presence of muscovite,silty to granular grain sizes,well sorted and deposited in a meandering setting;(6) the poorly-sorted sandstone.It is poorly sorted,poorly-graded,and coarse-grained,with erosive surfaces to underlying facies,and deposited in a fluvial environment;(7) the heterolithic clayey sandstone,poorly graded,grayish,with a degree of organic richness,suggesting an anoxic lacustrine environment;and(8) the grayish claystone which is nonlithic and rarely ferruginized marking the Upper Miocene/Eocene boundary.One main palynological zone,i.e.,the Echitricolporites spinosus assemblage zone,has been established.The base of the studied section at 385 m is characterized by the last up-hole occurrence of Grimsdalea magnaclavata suggestive of Eocene boundary while the overlying sediments are characterized by Late Miocene marker species such as E.spinosus,Elaeis guineensis,Anthocerus sp.,Nymphaea lotus,and Retistepho.nocolpites gracilis.The Chad Formation is dated as Late Miocene age unconformably overlying the Eocene Kerri-Kerri Formation which indicated that the Chad Formation was probably deposited during an alternation of lacustrine and continental settings,due to climatic change.
基金supported by the National Natural Science Foundation of China(Grant No.41630753)。
文摘Quaternary palynology plays a pivotal role in investigating global climate change and various other research fields,serving as an essential tool for the quantitative analysis of paleoenvironment changes.However,due to the vast diversity of terrestrial ecosystems and intricate interactions between vegetation,climate,and human activities,further advancements are required in the following aspects within this discipline.(1)The accuracy of classification in pollen morphology and fossil pollen identification needs improvement,particularly at the species level.This represents a significant challenge in present Quaternary palynology.Computer-aided intelligent recognition holds promise as a solution for species identification based on more detail pollen morphology.(2)Most pollen-based vegetation and climate reconstructions overlook the significance of bare ground.Neglecting bare ground can lead to substantial inaccuracies when quantitatively reconstructing past vegetation and climate.(3)While pollen records provide reliable information on paleoclimate changes,current quantitative climate reconstruction models heavily rely on modern pollen datasets derived from present-day vegetation disturbed more or less by human activities.This introduces bias and uncertainties into paleoclimate reconstruction.(4)Although pollen can serve as an indicator of human activities,accurately quantifying the intensity of human influence remains challenging.Improving accurate identification of crop pollen,reconstructing reliable land cover/use data,and integrating multidisciplinary data may enhance the identification and quantification of signals related to human activity in pollen records.
基金The authors are thankful to the Director(Prof.Mahesh G.Thakkar),Birbal Sahni Institute of Palaeosciences,Lucknow for providing the necessary permission and laboratory facilities to carry out this work(BSIP/RDCC/Publication no.73/2024-25)Author(SM)expresses sincere thanks to DST(Govt.of India)project no.EEQ/2018/000303 for the financial support.
文摘The Permian-Triassic(P/T)transition is marked by the most severe mass-extinction event of the Phanerozoic.Although much is known about this event in the marine realm,there are many open questions regarding what happened during this period to many continental biota.In the case of plants,a drastic mass-extinction event has even been negated by some authors.To add about the knowledge on continental biota in India during this crucial time period,the present study analysed the palynology,palynofacies,organic geochemistry(biomarkers),stable isotopes,and charcoal within the subsurface Gondwana deposits of the Kamthi Formation(late Permian-early Triassic)from core TTB-7 from the Tribida block,located in the Talcher Coalfield of the Mahanadi Basin,India.The primary objectives are to validate the age of the strata,ascertain the palaeodepositional setting of the palaeomire,and propose palaeobotanical evidence regarding the occurrence of wildfires within this stratigraphic succession and changes in floral content across the P/T transition.The palynological study proposes two palynoassemblage zones,Densipollenites magnicorpus and Klausipollenites schaubergeri,suggesting a latest Permian(Lopingian)and early Triassic(Induan?)age for the studied succession,respectively.The age is also inferred based on correlation with coeval assemblages from India and other Gondwana continents.The palynoassemblages reveal the dominance of Glossopteridales and Coniferales along with Filicales,Lycopsidales,Equisetales,Cordaitales and Peltaspermales.The relatively higher values of the carbon preference index and terrigenous/aquatic ratio also suggest higher plant input.However,a bimodal n-alkane distribution pattern suggests the contribution of terrigenous and microbial sources.Although the occurrences of long-chain alkanes indicate input of higher plants,the low Pwax values(<0.26)suggest relatively less contribution.The Paqvalues(≅1)and amorphous organic matter(av.33.24%)suggest a significant macrophyte input in the studied samples,pointing to the occurrence of moderate aquatic conditions in the basin.Furthermore,the distribution of hopanoids and the content of degraded organic matter(av.29.96%)reflect the bacterial degradation of organic matter.Also,the δ^(13)C values of the studied section varied from−31.2‰to−21.8‰.A large carbon isotopic offset of 9.4‰across the P/T transition,Pr/Ph ratio(0.3–1.3)and shift in the distribution pattern of palynofacies components is indicating a significant change in climatic conditions.Moreover,the presence of macroscopic charcoal fragments of gymnospermous affinity with pre-charring colonization by fungi provides evidence for wildfire occurring during the Lopingian(Late Permian)in this basin.
文摘This study explores the application of YOLOv10,a cutting-edge object detection framework,to automate the identification and classification of Batioladinium longicornutum.Utilizing a dataset of 137 annotated images,we trained and validated the model to distinguish B.longicornutum from other species with a mean Average Precision(mAP@0.5)of 62.0%.The methodology incorporated robust data augmentation techniques and evaluation metrics,including precision-recall analysis,confusion matrices,and cross-validation.YOLOv10’s architecture facilitated accurate feature extraction and efficient classification,even with a relatively small dataset.While this study focuses on species-level identification,future work will extend to morphological and preservation state classifications,offering broader applications in automated palynology.These findings demonstrate the potential of YOLOv10 to revolutionize taxonomic workflows and enhance the efficiency of paleontological research.
基金The research of VB is conducted in the scope of the internal research project“WEGETA”at the Croatian Geological Survey,funded by the National Recovery and Resilience Plan 2021-2026 of the European Union-NextGenerationEU,and monitored by the Ministry of Science,Education and Youth of the Republic of Croatia.
文摘The Toarcian Oceanic Anoxic Event(T-OAE,∼183 Ma)is marked in the sedimentary record by a sharp negative carbon isotope excursion,thought to be causally linked to the emplacement of the Karoo-Ferrar Large Igneous Province and the associated release of^(12)C-enriched carbon.The T-OAE coincided with global climate and environmental changes,as well as biotic events,indicating substantial modifications in ecosystems.Recent studies have focused on the evidence of geological responses to the T-OAE in Early Jurassic terrestrial basins in China,particularly the Sichuan Basin.Nevertheless,debate remains over the identification of this event,owing to inadequate age-constraints of many sections,and a lack of robust correlations of the carbon isotope records.Moreover,the long-term evolution of the terrestrial carbon isotope record through the Early Jurassic,and its correlation to marine records,is still not firmly established.In this paper,we present new carbon isotope analyses of carbonate(δ^(13)C_(carb))from lacustrine carbonates and terrestrial organic matter(δ^(13)C_(org))from bulk rocks within the Ma’anshan and Da’anzhai members of the Ziliujing Formation from the Dacao‘D’(DCD)section in the eastern Sichuan Basin.Palynological-palynofacies analysis reveals a predominance of Classopollis pollen together with marker taxa such as Ischyosporites variegatus,Contignisporites problematicus,in the palynological assemblage,indicating a Pliensbachian–Toarcian age.A negative carbon isotope excursion(NCIE)is recorded in the organic carbon isotope data at the topmost part of the Pliensbachian Ma’anshan Member,which can be correlated to the Pliensbachian–Toarcian Boundary Event.This is followed,in the Toarcian Da’anzhai Member,by a major NCIE recorded in both organic matter and carbonate carbon isotope data which can be correlated to the T-OAE NCIE.A long-term carbon isotope record spanning the Sinemurian to Toarcian in Sichuan terrestrial sediments is also been reconstructed and its correlation with coeval marine records is proposed.A broader review of δ^(13)C data from Chinese terrestrial basins spanning the Pliensbachian–Toarcian highlights a distinct^(13)C-depleted signature in the Sichuan Basin compared to basins at higher latitudes.Changes in latitudinal gradients and organic matters in the lake sediments were likely important factors influencing the amplitudes of the T-OAE NCIE and the carbon isotope values in terrestrial sedimentary records.
基金conducted under the National Natural Science Foundation of China(No.41172022)Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20120211110022,20100211110019)the Fundamental Research Funds for the Central Universities(No.lzujbky2014-285)
文摘Fossil bamboo leaves and pollen from Upper Miocene deposits of the Shengxian Formation in Tiantai and Ninghai counties, eastern Zhejiang, China represent a rare record in Asia. The distinctive pseudopetiole and parallel venation of the leaf blades and the clearly thickened annulus of the pollen aperture place them in the subfamily Bambusoideae. Morphological analysis supports the determination of these fossil leaves as belonging to the genus Bambusium and two new species are described. Bambusium latipseudopetiolus Q.J. Wang et B.N. Sun sp. nov. has a distinctly wide pseudopetiole of 0.23 cm in width and 0.40 cm in length, several vascular bundles on parallel veins, and 5-8 lateral veins on both sides of the midrib. Bambusium longipseudopetiolus Q.J. Wang et B.N. Sun sp. nov. has a distinctly long pseudopetiole of 0.60 cm in length and 0.10 cm in width, several vascular bundles on the pseudopetiole, and 6 lateral veins on both sides of the midrib. Pollen grains from the same layer provide additional evidence of bamboos. They are characterized by 32.0-51.0 μm in diameter, a round pore 3.0-4.0 μm in diameter with a broad thickened annulus 2.5-3.5 μm around, and several conspicuous secondary folds on the exine surface. The morphological analysis leads to their assignment to Graminidites bambusoides Stuchlik. These fossils are important for the study of bamboo phytogeography in China. They demonstrate that there were bamboos growing in southeastern China during the Late Miocene and that bamboos in Zhejiang begin to diversify no later than the Late Miocene. In combination with bamboo fossils from other places, it seems that bamboos had a wide distribution across southern China during the Miocene, ranging from southwestern Yun＇nan to southeastern Zhejiang.
基金supported by Special Basic Research Program of Ministry of Science and Technology of China (Grant No. 2006FY120300)National Committee of Stratigraphy of China. V. Vajda acknowledges the financial support provided by Swedish Research Council (VR, Grant No. 2007-4509)+1 种基金V. Vajda is a Swedish Royal Academy of Sciences Research Fellow founded through the Knut and Alice Wallenbergs Foundationa contribution to UNESCO-IUGS IGCP Project 506
文摘The Triassic-Jurassic （Tr-J） boundary marks a major extinction event, which （～200 Ma）resulted in global extinctions of fauna and flora both in the marine and terrestrial realms. There prevail great challenges in determining the exact location of the terrestrial Tr-J boundary, because of endemism of taxa and the scarcity of fossils in terrestrial settings leading to difficulties in linking marine and terrestrial sedimentary successions. Investigation based on palynology and bivalves has been carried out over a 1113 m thick section, which is subdivided into 132 beds, along the Haojiagou valley on the southern margin of the Junggar Basin of the northern Xinjiang, northwestern China. The terrestrial Lower Jurassic is conformably resting on the Upper Triassic strata. The Upper Triassic covers the Huangshanjie Formation overlaid by the Haojiagou Formation, while the Lower Jurassic comprises the Badaowan Formation followed by the Sangonghe Formation. Fifty six pollen and spore taxa and one algal taxon were identified from the sediments. Based on the key-species and abundance of spores and pollen, three zones were erected： the Late Triassic （Rhaetian） Aratrisporites-Alisporites Assemblage, the Early Jurassic （Hettangian） Perinopollenites-Pinuspollenites Assemblage, and the Sinemurian Perinopollenites-Cycadopites Assemblage. The Tr-J boundary is placed between bed 44and 45 coincident with the boundary between the Haojiagou and Badaowan formations. Beds with Ferganoconcha （？）, Unio-Ferganoconcha and Waagenoperna-Yananoconcha bivalve assemblages are recognized. The Ferganoconcha （？） bed is limited to the upper Haojiagou Formation,Unio- Ferganoconcha and Waagenoperna- Yananoconcha assemblages are present in the middle and upper members of the Badaowan Formation. The sedimentary succession is interpreted as terrestrial with two mainly lake deposit intervals within Haojiagou and Badaowan formations, yielding fresh water algae and bivalves. However, the presence of brackish water algae Tasmanites and the marine-littoral facies bivalve Waagenoperna from the Badaowan Formation indicate that the Junggar Basin was influenced by sea water caused by transgressions from the northern Tethys, during the Sinemurian.
基金supported by the National Natural Science Foundation of China(41102106)
文摘Because of the unique geographical location and important ecological effect of the Qinling Mountains, reconstruction of its vegetation and climate needs comprehensive research. We need to consider a multiple-proxy approach to gain more information on recovering the paleovegetation and climate in the Qinling Mountains. Black carbon （BC） is produced by the incomplete combustion of vegetation and fossil fuels, and is a good proxy, recording paleoenvironmental information. However, in the Qinling Mountains, what are the characteristics of the BC, and whether BC stable carbon isotope （δ^13CBc） can be used as a new proxy to study ancient vegetation, still need further study. In order to establish a sound basis for studying paleoenvironmental by BC proxy in the Qinling Mountains, we carried out systematic and detailed study on modern process of BC on the northern slope of the mountains. We analyzed stable carbon isotopes and carbon concentration of organic carbon （% SOC, δ^13Csoc） and BC （%BC, δ^13CBc）, and identified the pollen assemblages from systematically sampled surface soil. The results show that the calculated ratio of C4 plants in the vegetation （%C4） based on the δ13Csoc data reflects a similar distribution of C4 plants in the surface vegetation and the pollen assemblage. The δ^13Cac values have a strong positive correlation with δ13Csoc values, and their difference （△13CSOC-BC） is in the low range. These data indicate that δ^13CBC and δ^13CSOC have very similar characteristics. Surface soil δ13BC values can indicate surface vegetation as effectively as δ^13Csoc values, and the δ^13CBC proxy can be used effectively in paleovegetational research in the northern slope of Qinling Mountains.
基金a contribution to the scientific project "The Study of the Fossil Insects in Lebanon and their Outcrops:Geology of the Outcrops - Historical and Biodiversity Evolution" the team project:"Biodiversity:Origin,Structure, Evolution and Geology" financed by the Lebanese University to the first author(DA)
文摘An amber-bearing lignitic layer of sandy clay from the Lower Cretaceous of Central Lebanon （Mderej-Hammana）yielded a well-preserved,moderately variegated palynoflora,which origin is mixed between land plants and marine microflora.Its detailed analysis led to fulfill its inventory,to propose a paleoenvironmental reconstruction,and to draw the paleoclimate which prevailed over the region：an estuarian area under a rather humid,temperate climate;a variety of ferns grew near the shore-side and in the inward land.A tiny piece of amber containing angiospermous pollen grains of stratigraphical interest allows a precise dating.The marine microflora,poorly diversified,includes chitinous foraminifer linings and dinoflagellate cysts,among which Early Aptian guide taxa are present;their occurrence slightly narrows the stratigraphical range indicated by some palynological taxa which are related to land plants.
基金the National Natural Science Foundation of China (Grant #41872003)
文摘Two Upper Devonian to Lower Carboniferous sections,namely the Bulongguoer and Haer(Gennaren area)in the Junggar Basin,Central Asian Orogenic Belt,in northwestern China were examined with regard to ichnology and palynology.The deposits of the Hongguleleng Formation and Namu Member of the Heishantou Formation,respectively,are mostly unbioturbated or poorly bioturbated,with poorly diversified trace fossils,which indicate unfavourable conditions for the burrowing benthic community during the Late Devonian and Early Carboniferous.The main factor governing the growth of the bioturbating population was the rapid sedimentation of fine-grained,volcanic material documented as tempestites,which buried the benthic fauna.In the Bulongguoer section,the presence of miospores Teichertospora torquata and Grandispora gracilis enabled identification of the broad Teichertospora torquata–Grandispora gracilis Miospore Zone from the transitional Frasnian/Famennian interval.More accurate identification of palynostratigraphical levels(DE and CZ Miospore zones)is only tentative.On the basis of palynofacies analysis,samples from the lower Bulongguoer section indicate deposition in more proximal conditions,whereas samples from the top of the section indicate deposition in a more distal environment.In the Haer section,only a general biostratigraphic indication for the Tournaisian was possible,owing to poor preservation of organic matter.
基金This work was funded by the State Program(Grant No.0135-2019-0044)of the Geological Institute of the Russian Academy of Sciences.
文摘The lithological and geochemical composition and conditions of formation of the coal-bearing deposits of the Kizel Coal Basin in the Perm region of the Urals(central Russia)are described using the two most representative sections,Gubakha-Stary Most and Krestovaya Mountain,based on a detailed“layer-by-layer”technique.Brief characteristics of the Lower Carboniferous paleosols from fossil paleosol(FPS-)profiles of the studied region are given.Special attention is paid to the parent vegetation of the coal-forming processes,based on an analysis of both plant macrofossils and palynoflora.The peat accumulation in conditions of permanent incoming of clastic material from the Paleo-Urals to the Kizel Basin was probably effective only in more or less stable environments,when the accumulated organic matter produced by plant mortmass was not dissolved by clastic particles.Thus,the conditions of coal-forming are reconstructed as a forest swamp,where the main dominants are represented by lycopodiopsids of the order Lepidodendrales,predominantly Lepidodendron veltheimii.These plants in particular were the source of the initial organic matter for the peat(and later coal)of the Kizel Coal Basin.
文摘Since the time of the rainy Holocene, there have been periods of consecutive rain and drought on Egypt. Study of carbon 14 in the long-lived coniferous tree rings could see activity in the sun （spots and solar flares） during eleven years cycle, as well as knowledge of possible flooding of the Nile and the periods of increase and decrease of the extent necessary to meet the soil around Lake Qarun in Fayoum-Egypt. From historical records in ancient Egypt and Muslim countries, the possible link between periods of the disappearance of sunspots on the solar disc for several years and is known to inch lower level and role of the minimum level of Mandour creeping ice on Southern Europe to the Mediterranean Sea, and the offset of the drought in North Africa and the Sahel region of Africa during the last thousand years. Analyzed pollen fossils of the overlapped layers of soil in two areas of the Delta were Avaris in Sharkiya Province and Mendes in Dakahliya Province. The study pointed out that there are differences due to environmental conditions, demonstrated by the analysis of soil pH, increased electrical connectivity also, the evidence of sulfates and chlorides indicate high salinity of Mendes and Avaris. Also the analysis of fossil pollen of successive layers of soil for both regions resulted in findings of fossil pollen of the species Chenopodiaceae by 51.2%, in Mendes, while, 7% in the Avaris. This is strong evidence of the existence conditions of salt in Mendes than Avaris archaeological sites.
基金Supported by National Natural Science Foundation of China(No.31670215).
文摘The Permian is one of the most important periods during which the vegetative earth witnessed the transition from icehouse to greenhouse climate and the global environment changes.Organisms on the planet encountered great challenge and the demise of swamp caused the extinction of arborescent lycopods and the rising of Mesophytic plants accomplished the floral transition from the Paleophytic to Mesophytic vegetation.In order to depict the climatic changes and floral succession in the middle and high latitudes of the North Hemisphere,palynological investigation was engaged,and 40 samples collected from the uppermost of Taerlang Formation,Hongyanchi Formation and Quanzijie Formation in the Tianshan Town,Turpan-Hami Basin,eastern Xinjiang,China.The result shows that the palynoflora in the studied area is composed of 50 species of 33 genera,dominated by disaccites and striatiti gymnosperm pollen,and characterized by diverse Protohaploxypinus,Hamia-pollenites,Alisporites and Klausipollenites.It is quite similar to those Middle and Late Permian palynological assemblages reported in the Dalongkou section and other localities in southern margin of Junggar Basin,and aged at Middle and Late Permian.The diversity of typical Angara and sub-Angara pollen,such as Falcisporites,Alisporites,Protohaploxypinus,Vittatina,Lunatisporites,Hamiapollenites,etc.indicates that the studied palynoflora belonged to the sub-Angara phytoprovince,while the presence of Lueckisporites virkkiae implied Euramerica pollen intruded northward sometimes.The paleoclimate of the studied area might be warm and humid with fluctuated dry seasons during the late Guadalupian and early Lopingian time.
文摘A well-preserved Late Cretaceous-Paleogene palynological flora from the middle member of the Tsagajan Formation and the upper member of the Tsagajan Formation including the Kivda Beds is reported for the first time from the Arkhara-Boguchan brown coal mine, southeastern part of the Zeya-Bureya Basin. Four palynocomplexes were established for the Cretaceous-Tertiary transition. The climate and phytocoenoses were also analyzed,based on the detailed palynological data. The results are coincident with those of mega-flora studied by Akhmetiev et al. (2002).
