During the Late Miocene,numerous medium to large-sized herbivores,that resemble the living Ovibos in skeletal morphology,dispersed throughout the Holarctic realm and comprised eleven genera:Lantiantragus,Shaanxispira,...During the Late Miocene,numerous medium to large-sized herbivores,that resemble the living Ovibos in skeletal morphology,dispersed throughout the Holarctic realm and comprised eleven genera:Lantiantragus,Shaanxispira,Tsaidamotherium,Criotherium,Mesembriacerus,Hezhengia,Urmiatherium,Parurmiatherium,Plesiaddax,Sinotragus,and Prosinotragus.These genera are primarily found in eastern Asia,in which nine genera are found in northern China,as well as in countries in eastern Europe and western Asia.They are distinguished by unique characteristics,including a perpendicular braincase,specialized horn cores,and a robust basioccipital.Previous studies have often classified these‘ovibovin’bovids as part of the conventional subfamily/tribe Ovibovinae/Ovibovini,along with extant Ovibos.Nevertheless,an increasing number of studies do not support the monophyly of the subfamily/tribe Ovibovinae/Ovibovini,nor is a close relationship likely between these Late Miocene‘ovibovin’bovids and extant Ovibos.Among the eleven genera of‘ovibovin’bovids,Plesiaddax,Hezhengia,and Urmiatherium are often considered to have a very close relationship and conventionally form the tribe Urmiatheriini.However,previous phylogenetic analyses do not support the monophyly of Urmiatheriini.This paper presents a summary of the transmutation of the terms Ovibovidae/Ovibovinae/Ovibovini/Ovibovina,the temporal and spatial distribution of the Late Miocene‘ovibovin’bovids in Eurasia,the principal characteristics of these taxa,and the previous phylogenetic analyses.展开更多
Late Miocene woods were investigated from the Luhe Basin in Chuxiong Borough, central Yunnan, China. The calcified woods preserved in the Shigucun member of the Shihuiba Formation, are represented by fallen logs and s...Late Miocene woods were investigated from the Luhe Basin in Chuxiong Borough, central Yunnan, China. The calcified woods preserved in the Shigucun member of the Shihuiba Formation, are represented by fallen logs and stumps. Two species of fossil wood, Taxodioxylon cryptomeripsoides Schonfeld 1953 and T. cunninghamioides Watari 1948, are described. Their anatomical structure shows striking similarities to the woods of Cryptomeria and Cunninghamia respectively. That the two fossil woods are classed in the Taxodiaceae suggest a subtropical, humid, and warm environment in Lithe during Late Miocene. They compare favorably to other fossil specimens and species reported from localities ranging from Cretaceous to Pliocene. This is the first record of the presence of the species T. cryptomeripsoides and T. cunninghamioides in late Miocene of Yunnan.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
A new species, Tsuga nanfengensis sp.nov.（Pinaceae）, is described on the basis of lignified fossil wood from the late Miocene of the Xianfeng Basin, central Yunnan, southwestern China.Detailed observation of the fos...A new species, Tsuga nanfengensis sp.nov.（Pinaceae）, is described on the basis of lignified fossil wood from the late Miocene of the Xianfeng Basin, central Yunnan, southwestern China.Detailed observation of the fossil wood specimens show the following characteristics： distinct growth rings, absence of resin canals, uniseriate bordered pits in the radial wall of tracheids, ray tracheids and piceoid and cupressoid cross-field pits.These features indicate similarities to the wood of extant Tsuga canadensis, T.chinensis, and T.dumosa.According to the fossil record, Tsuga was present in Xundian County during the Miocene.Today Tsuga is drought intolerant, preferring wet conditions with no extant species growing naturally in Xundian County.The presence of Tsuga in the Miocene of Xundian County indicates a humid climate consistent with previous palaeoclimatic reconstructions showing a wetter and probably shorter dry season in the Miocene, relative to the present day.Therefore, the change in the local climate such as increasing aridity through the Miocene might explain the local extinction of Tsuga from central Yunnan.展开更多
The uplift of the Ailao Shan-Diancang Shan （ASDS） along the Ailao Shan-Red River （ASRR） shear zone is an important geological event in the southeastern margin of Qinghai-Tibet Plateau tectonic domain in the Late C...The uplift of the Ailao Shan-Diancang Shan （ASDS） along the Ailao Shan-Red River （ASRR） shear zone is an important geological event in the southeastern margin of Qinghai-Tibet Plateau tectonic domain in the Late Cenozoic, and it preserves important information on the structures, exhumationai history and tectonic evolution of the ASRR shear zone. The uplift structural mode and uplift timing of the ASDS is currently an important scientific topic for understanding the ASDS formation and late stage movements and evolution of the ASRR shear zone. The formation of the ASDS has been widely considered to be the consequence of the strike-slip movements of the ASRR shear zone. However, the shaping of geomorphic units is generally direct results of the latest tectonic activities. In this study, we investigated the timing and uplift structural mechanism of the ASDS and provided the following lines of supportive evidence. Firstly, the primary tectonic foliation of the ASDS shows significant characteristic variations, with steeply dipping tectonic foliation developed on the east side of the ASDS and the relatively horizontal foliation on the west side. Secondly, from northeast to southwest direction, the deformation and metamorphism gradually weakened and this zone can be further divided into three different metamorphic degree belts. Thirdly, the contact relationship between the ASDS and the Chuxiong basin-Erhai lake is a normal fault contact which can be found on the east side of the ASDS. 40^Ar/^39 Argeochronology suggests that the Diancang Shan had experienced a fast cooling event during 3-4 Ma. The apatite fission track testing method gives the age of 6.6-10.7 Ma in the Diancang Shan and 4.6-8.4 Ma in the Ailao Shan, respectively. Therefore the uplift of the ASDS can be explained by tilted block mode in which the east side was uplifted much higher than the west side, and it is not main reason of the shearing movements of the ASRR shear zone. The most recent uplift stages of the ASDS happened in the Pliocene （3-4 Ma） and Late Miocene （6-10 Ma）.展开更多
Albizzia is a leguminous genus belonging to the subfamily Mimosoideae with approximately 150 modern species, widely distributed in the tropical and subtropical regions of Asia, Africa, Australia and America. Among the...Albizzia is a leguminous genus belonging to the subfamily Mimosoideae with approximately 150 modern species, widely distributed in the tropical and subtropical regions of Asia, Africa, Australia and America. Among them, 17 species are mainly distributed in southern and southwestern China. Abundant fossils of the subfamily Mimosoideae, including leaves, pods, flowers and wood, have been reported from the Cretaceous and Paleogene strata of the Northern Hemisphere. However, Neogene records of Mimosoideae are relatively scarce. In this study, fossil pods and leaves belonging to the genus Aibizzia from the Bangmai Formation of Yunnan, China were described. They were assigned to three species, including Albizzia scalpeUiformis Guo, Li and Xie Emended, Albizzia cf. kalkora （Roxb.） Prain and Albizzia sp. The occurrence of Albizzia fossils from Lincang not only gives important information on the Neogene plant diversity from Yunnan--a worldwide famous biological hotspot--but also provides additional evidence for its phytogeographic history.展开更多
The Xining basin is located in the northeastern margin of the Qinghai-Tibet Plateau. It is a rift basin formed in Mesozoic and Cenozoic and structurally belongs to the intersection of Kunlun and Qilian Mountains. Ceno...The Xining basin is located in the northeastern margin of the Qinghai-Tibet Plateau. It is a rift basin formed in Mesozoic and Cenozoic and structurally belongs to the intersection of Kunlun and Qilian Mountains. Cenozoic fluvial and lacustrine sedimentary strata are continuous in the Xining basin, with a thickness of more than 800 m, completely recording the deformation uplifting, weathering and denudation history and climate change process of the northeastern plateau. Currently, early Miocene Xijia fauna, early Middle Miocene Danshuilu fauna and late Middle Miocene Diaogou fauna are discovered in the Xining basin, which provide an important basis for the stratigraphic correlation of the Cenozoic strata in the Xining basin. However, in the next few decades, there are no reports about the large mammal fossils in the Xining basin, especially about late Miocene fauna. The author discovered a large amount of mammal fossils in the Neogene sedimentary strata in Huzhu area, Xining basin. According to the identification results of the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, these fossils mainly included Hipparion dongxiangense, Chilotherium sp., Parelasmotherium sp., Stephanocemas sp. and Kubanochoerus sp. and their age was early Late Miocene. Since the discovery of this set of fossils directly filled the blank that there were no large mammal fossils in the Xining basin in Late Miocene, it was very important for studying the magnetic stratigraphic chronology of fossil-forming strata and establishing the paleomagnetic chronology scale plate of mammal fossils. In this paper, the paleomagnetic data of the fossil-forming stratigraphic profile, Banyan profile, were measured and the paleomagnetic records were collected through high density sampling, and finally the paleomagnetic polarity column of the profile was established. The results showed that five positive and five negative polarity segments were recorded in Banyan profile, which corresponded well to the polarity between C3 Br.1 n-C4 n.2 n in the standard polarity column. The age of profile top was about 7.25 Ma and profile bottom was about 8.4 Ma, with an age range of 1.15 Ma. The mammal fossils discovered this time were exposed between positive and negative polarities N5 and R5 at the bottom of the profile, corresponding to C4 r.1 r at negative polarity and C4 n.2 n at positive polarity in the standard polarity column. The age of mammal fossils was about 8.3 Ma. The paleomagnetic chronology of the strata and paleontological fossils determined the absolute age of late Miocene mammal fossils and expanded the upper age of late Miocene Xianshuihe Formation(N1 xn) in the Xining basin, which had provided new basic data for further studying the stratigraphic deposition and correlation of late Cenozoic strata and regional environmental evolution.展开更多
Objective Xining basin is located in the northeastern Qinghai- Tibetan Plateau, which tectonic location belongs to a junction of the Kunlun and Qilian mountains. The southern, northern and western parts of the basin a...Objective Xining basin is located in the northeastern Qinghai- Tibetan Plateau, which tectonic location belongs to a junction of the Kunlun and Qilian mountains. The southern, northern and western parts of the basin are restricted by the Laji, Daban and Riyue mountains fault zones, and go eastward into the Longzhong basin in Gansu Province. A succession of Cenozoic lacustrine sedimentary strata has been well developed in the Xining basin, with sediments over 800 m thick.展开更多
The ancient Mediterranean was once dried up around6~5.3million years ago.It is a landmark event,which had great impact on global environment and climate.However,few references are available in the literatures on this ...The ancient Mediterranean was once dried up around6~5.3million years ago.It is a landmark event,which had great impact on global environment and climate.However,few references are available in the literatures on this topic,展开更多
Abundant plant fossils were found in the Upper Miocene Shengxian Formation,eastern Zhejiang Province,China,among which Trapa belongs to a dominant population.The fossil fruits of Trapa were well preserved with abundan...Abundant plant fossils were found in the Upper Miocene Shengxian Formation,eastern Zhejiang Province,China,among which Trapa belongs to a dominant population.The fossil fruits of Trapa were well preserved with abundant details.However,due to compaction during fossilization,Trapa fruits were often flattened,leading to the loss of some characteristic features.Thereby,a bias in taxonomic and phylogenetic studies would occur when such studies were based on these fruit fossils.In this study,we present the first quantitative three-dimensional reconstruction of compressed Trapa fruit fossils to restore their original morphology prior to burial.This approach provides a novel perspective for the identification and classification of compressed fruit fossils.The three-dimensional reconstruction of Trapa fruit fossils enabled accurate comparisons with extant species.We subsequently identified it as a new species,named Trapa radiatiformis L.Xiao sp.nov.,revealing differences from previously known taxa of Trapa.Importantly,our comparison suggests that the long lower horns and residual stalk may represent inherent characteristics of early Trapa fruits.However,these traits gradually degenerated during fruit evolution,resulting in morphological simplification during geological time.T.radiatiformis with primitive features exhibits good resemblance to Trapa natans fruit characteristics,which means it may be an ancestor of T.natans.We summarize the palaeogeographic distribution of fossil Trapa using previously published literature and demonstrate that the genus was mostprosperous in the Miocene and exhibited the same distribution as that at present.Additionally,through detailed morphological comparisons between Trapa and Hemitrapa fruits,along with phylogenetic analysis within the Primotrapa genus itself,we propose a homology between Trapa and Hemitrapa,suggesting that they could have a common ancestor.展开更多
TheÇorakyerler fossil locality in Anatolia reveals unique faunal elements.This study introduces Hystrix kayae sp.nov.,a new Late Miocene porcupine initially classified as Hystrix sp.Yavuz et al.,2018.This finding...TheÇorakyerler fossil locality in Anatolia reveals unique faunal elements.This study introduces Hystrix kayae sp.nov.,a new Late Miocene porcupine initially classified as Hystrix sp.Yavuz et al.,2018.This finding expands our knowledge of Late Miocene Anatolian porcupines,bringing the total number of known species to three.H.kayae sp.nov.is larger than Hystrix aryanensis and exhibits greater upper cheek tooth crown height.Its cheek tooth morphology differs from Hystrix depereti,and it possesses distinctive U-shaped choanae unlike Hystrix primigenia.TheÇorakyerler locality may predate sites with H.aryanensis and H.primigenia but aligns temporally with Hystrix parvae localities.This study enhances our understanding of Late Miocene porcupine diversity in Anatolia,emphasizing the importance ofÇorakyerler in unraveling the evolutionary history of these fascinating mammals.展开更多
Euryale （Nymphaeaceae） is a monotypic genus distributed in eastern Asia, but fossils in its native distribu- tion are sparse as compared to Europe where the genus has disappeared. Here, we describe a new fossil spec...Euryale （Nymphaeaceae） is a monotypic genus distributed in eastern Asia, but fossils in its native distribu- tion are sparse as compared to Europe where the genus has disappeared. Here, we describe a new fossil species, Euryale yunnanensis sp. nov., from the late Miocene Zhaotong Basin in southwestern China on the basis of seed remains. Char- acteristics including an ellipsoidal to almost spherical shape, a smooth surface, a germination cap that covers the micro- pyle, the separation of the hilum and germination cap （mi- cropyle）, elliptic testa surface cells with undulate margins and thickened cell walls collectively indicate a close affinity with the genus Euryale in Nymphaeaceae. Comparisons of seed morphology and anatomy demonstrate that the newly described fossil species differs from modem and other fossil species of Euryale and thus verify the assignment to a new fossil species. As the modem Euryale is an aquatic plant, preferably living in swamps and lakes with shallow and stable water, we hypothesize that a lake and/or swamp environment with shallow water was present near Shui- tangba in the Zhaotong Basin, where the Shuitangba homi- noid lived during the late Miocene. This inference is generally consistent with paleoenvironmental data extracted from avian, fish, frog, turtle and crocodile fossils, as well as from aquatic pollen. The fossil history suggests a compara- tively recent （Miocene） emergence of Euryale, which is roughly in agreement with the divergence time inferred from the molecular information.展开更多
The Huanghekou Sag is located at the southeast part of the Bohai Bay Basin, northern China. Large-scale shallow lake delta developed in the Neogene provided suitable geological conditions for the formation of a subtle...The Huanghekou Sag is located at the southeast part of the Bohai Bay Basin, northern China. Large-scale shallow lake delta developed in the Neogene provided suitable geological conditions for the formation of a subtle oil-gas reservoir in this area. The key for analyzing sandstone reservoir and sedimentary facies is by using seismic attributes(amplitude) to establish the relationship between lithology combination and seismic attributes. The lower unit of Late Miocene Minghuazhen Formation at the BZ34 block in the Huanghekou Sag was subdivided into 10 parasequence sets(PSS). Thicker sandstones mainly occurred in PSS1 and PSS10, whereas thin sandstones are mostly observed within other parasequence sets. This study presents statistics and analyses of lithology, i.e., statistics of root-meansquare(RMS) amplitude and lithology of well locations in different parasequence sets of the study area,as well as 1-D forward seismic models of 7 types of lithology combinations, the establishment of a spatial distribution of 2-D sandbody, forward seismic models etc. Our study indicates that high amplitude peaks correspond to thicker sandbodies, while low amplitude indicates non-development of sandbodies(generally less than 2 m), and medium amplitude agrees well with large sets of mudstones interbedded with medium and thinner sandstones. Different sand-mudstone combinations genetically reflect a combination of multiple micro-facies, therefore, amplitude features can predict sandbodies as well as facies characteristics.展开更多
The Upper Miocene Xiaohe Formation of the Yuanmou Basin in Yunnan Pro- vince, southwestern China, is famous for its hominoid fauna and is important for studying the Late Cenozoic human and mammal evolution. Abundant f...The Upper Miocene Xiaohe Formation of the Yuanmou Basin in Yunnan Pro- vince, southwestern China, is famous for its hominoid fauna and is important for studying the Late Cenozoic human and mammal evolution. Abundant fossil wood was found associated with this fauna, which provided important evidence for palaeoenvironmental reconstruction of the basin. Among the fossil wood, two different taxa have been identified namely, Quercoxylon sp. （Fagaceae） and Pterocarya sp. （Juglandaceae）. Based on the habitats of their Nearest Living Relatives （NRLs）, it is suggested that upland subtropical evergreen broad-leaved forest dominated by QuercuslLithocarpus was common around the basin, while a lowland deciduous broad-leaved forest dominated by Pterocarya was present on the river bank of the basin during the Late Miocene.展开更多
The vertebrate fossil record from the Balearic Islands(western Mediterranean)has improved considerably over the past decade,especially in Mallorca and Menorca.In Menorca,the Pliocene terrestrial fauna was updated by t...The vertebrate fossil record from the Balearic Islands(western Mediterranean)has improved considerably over the past decade,especially in Mallorca and Menorca.In Menorca,the Pliocene terrestrial fauna was updated by the discovery and description of the large-sized leporid Nuralagus,several reptiles and an amphibian.In Mal-lorca,paleontological exploration yielded 2 deposits with a Late Miocene/Early Pliocene chronology,Calóden Rafelino(CdR)and Na Burguesa-1(NB-1).So far,4 new mammalian taxa and 2 new reptiles have been iden-tified for the CdR deposit,whereas the faunal assemblage from the recently discovered deposit(Apr 2012)of NB-1 is currently composed of,at least,6 terrestrial mammals,8 reptiles and an amphibian.Its faunal composi-tion and some primitive characteristics of the obtained taxa suggest that the chronology of this deposit is slight-ly earlier than the CdR.The terrestrial vertebrates recorded in these 2 Mallorcan deposits are changing the view of the paleofaunal assemblage previously known for the Plio-Pleistocene of the island.Morphological charac-teristics displayed by some of the taxa suggest that these faunas would be at the beginning of an isolated evo-lution.In this paper we present a preliminary report on the fossils recovered from the NB-1 deposit,as well as some unpublished data from CdR,and we analyze the whole fauna from both Mallorcan deposits,focusing on taxonomical and paleobiogeographical aspects.展开更多
With a thick sequence of early Eocene to Pleistocene terrestrial records, the Qaidam Basin on the northern Tibetan Plateau provides an important sedimentary archive for understanding the paleoenvironmental evolution o...With a thick sequence of early Eocene to Pleistocene terrestrial records, the Qaidam Basin on the northern Tibetan Plateau provides an important sedimentary archive for understanding the paleoenvironmental evolution of the northeast Tibetan Plateau. In this study, specimens of fossil fish remains are collected from the late Middle Miocene（Serravallian, -12 Ma） of the middle member of the Shang Youshashan Formation, Dahonggou（DHG） section, in the northern Qaidam Basin. Based on a systematic study of these materials, the remains have assigned to Cyprinidae, with typical pharyngeal teeth and dorsal fin spines with serrations on the posterior edge. Our discovery improves understanding of the cyprinid fish distribution characteristics in the Qaidam Basin during the Cenozoic. Cooccurrences of terrestrial brackish ostracod species Cyprideis and long chain alkenonesin the layer indicate that the studied cyprinid fish lived in a generally large brackish to saline water body during the late middle Miocene（Serravallian）, when the climate of Qaidam Basin was still not sufficiently dry to form an extreme saline water lake.展开更多
Equisetum(Equisetaceae)has long been a focus of attention for botanists and palaeontologists because,given its extensive and well-documented fossil record,it is considered the oldest extant vascular plant and a key el...Equisetum(Equisetaceae)has long been a focus of attention for botanists and palaeontologists because,given its extensive and well-documented fossil record,it is considered the oldest extant vascular plant and a key element in understanding vascular plant evolution.However,to date,no authentic fossil evidence of Equisetum has been found from the Indian Cenozoic.Here,we describe a new fossil species,namely,E.siwalikum sp.nov.,recovered from the middle Siwalik(Late Miocene)sediments of Himachal Pradesh,western Himalaya.We identified fossil specimens based on morphological and epidermal characters.In addition,X-Ray diffraction(XRD)analysis was used to determine the mineral composition of compressed stems of Equisetum.The close affinity of our recovered Siwalik fossils to Equisetum is supported by the presence of both macromorphological and epidermal characters.Because Equisetum generally grows in wet conditions around water reservoirs,our findings indicate that the fossil locality was humid and surrounded by swamp and lowland regions during deposition.Ample fossil evidence indicates that this sphenopsid once existed in the western Himalaya during the Siwalik period.However,at present Equisetum is confined to a particular area of our fossil locality,probably a consequence of severe environmental changes coupled with competition from opportunistic angiosperms.Our discovery of Equisetum fossils in appreciable numbers from the Siwalik sediments of the Himachal Himalayas is unique and constitutes the first reliable recognition of Equisetum from the Indian Cenozoic.展开更多
The Liupan Mountains,one of the important mountain ranges in western China,are located on the boundary between the northeastern Tibetan Plateau and the Ordos Block.The uplift history of the Liupan Mountains remains co...The Liupan Mountains,one of the important mountain ranges in western China,are located on the boundary between the northeastern Tibetan Plateau and the Ordos Block.The uplift history of the Liupan Mountains remains controversial.Loess deposits are good tracers of regional tectonic and geomorphic changes,because loess is sensitive to erosion and the formation and preservation of loess requires relatively flat highlands and relatively stable tectonic environments.We investigated the distribution of Neogene loess deposits on the western piedmont of the Liupan Mountains and examined a near-continuous loess section(Nanping section)on the piedmont alluvial highlands.Correlation of magnetic susceptibility stratigraphy with the QA-ⅠMiocene loess sequence dates this 56-m section covering the interval from~8.1 to 6.2 Ma.The lower boundary age of this section,together with previously reported Zhuanglang red clay(sand-gravel layers with intercalated loess during~9–8 Ma and near-continuous loess during~8–4.8 Ma)and Chaona red clay(~8.1–2.58 Ma),indicates that the Liupan Mountains were uplifted in the late Miocene(~9–8 Ma)and basically formed by~8 Ma,attesting to no intense mountain building since that time.In addition,based on the information from the Zhuanglang core and the QA-Ⅰsection,we infer that sizable parts of the Liupan Mountains were uplifted during the late Oligocene–early Miocene and did not experience intense uplift during~22–9 Ma.展开更多
Mammals have high dispersal ability,and many lineages can spread across the continents when a landbridge appears.Here,we summarize the dispersal of mammals between the Old and New World at the end of the Miocene.Our a...Mammals have high dispersal ability,and many lineages can spread across the continents when a landbridge appears.Here,we summarize the dispersal of mammals between the Old and New World at the end of the Miocene.Our analysis suggested that the three phases of dispersal represented the largest dispersal tide during the Neogene,and the direction of dispersal is dominated by being from the Old to New World.Judging from the components that crossed the dispersal corridor,the Arctic environment near the Beringia corridor in the first phase(~7.5 Ma)is a mixed environment,and in the second phase(~6.5 Ma)is an open environment,and in the third phase(~5.8 Ma and continue to the Pliocene)is a wooded(closed)environment.A clear trend of eastern Asian humidification driven by Asian monsoon and the global C4 grassland expansion explain this dispersal pattern.The boost of mammalian dispersals is controlled by the heterogeneity of environmental changes in different continents.展开更多
In the last 30 ma, the passive continental margin of South America and the Amazonian basin experienced three periods of major sea level inundation;viz. at around 20 ma, at around 10 ma and at around 3 ma. The establis...In the last 30 ma, the passive continental margin of South America and the Amazonian basin experienced three periods of major sea level inundation;viz. at around 20 ma, at around 10 ma and at around 3 ma. The establishment of the immense Amazonian rainforest ecosystem covering some 6 million square km can neither have occurred during the periods of high sea level nor at the intermediate periods of arid or semi-arid climatic conditions. Therefore, the origin of the Amazonian rainforest of present-day dimensions must be set at the Late Miocene. The establishment of the Amazonian rainforest implied the withdrawal of enormous quantities of water from the global hydrological cycle. The drastic increase in evaporation leading to the Messinian salinity crisis in the Mediterranean occurred at the same time as the Amazonian rainforest (sensu hodierno) establishment suggesting a causal linkage.展开更多
文摘During the Late Miocene,numerous medium to large-sized herbivores,that resemble the living Ovibos in skeletal morphology,dispersed throughout the Holarctic realm and comprised eleven genera:Lantiantragus,Shaanxispira,Tsaidamotherium,Criotherium,Mesembriacerus,Hezhengia,Urmiatherium,Parurmiatherium,Plesiaddax,Sinotragus,and Prosinotragus.These genera are primarily found in eastern Asia,in which nine genera are found in northern China,as well as in countries in eastern Europe and western Asia.They are distinguished by unique characteristics,including a perpendicular braincase,specialized horn cores,and a robust basioccipital.Previous studies have often classified these‘ovibovin’bovids as part of the conventional subfamily/tribe Ovibovinae/Ovibovini,along with extant Ovibos.Nevertheless,an increasing number of studies do not support the monophyly of the subfamily/tribe Ovibovinae/Ovibovini,nor is a close relationship likely between these Late Miocene‘ovibovin’bovids and extant Ovibos.Among the eleven genera of‘ovibovin’bovids,Plesiaddax,Hezhengia,and Urmiatherium are often considered to have a very close relationship and conventionally form the tribe Urmiatheriini.However,previous phylogenetic analyses do not support the monophyly of Urmiatheriini.This paper presents a summary of the transmutation of the terms Ovibovidae/Ovibovinae/Ovibovini/Ovibovina,the temporal and spatial distribution of the Late Miocene‘ovibovin’bovids in Eurasia,the principal characteristics of these taxa,and the previous phylogenetic analyses.
文摘Late Miocene woods were investigated from the Luhe Basin in Chuxiong Borough, central Yunnan, China. The calcified woods preserved in the Shigucun member of the Shihuiba Formation, are represented by fallen logs and stumps. Two species of fossil wood, Taxodioxylon cryptomeripsoides Schonfeld 1953 and T. cunninghamioides Watari 1948, are described. Their anatomical structure shows striking similarities to the woods of Cryptomeria and Cunninghamia respectively. That the two fossil woods are classed in the Taxodiaceae suggest a subtropical, humid, and warm environment in Lithe during Late Miocene. They compare favorably to other fossil specimens and species reported from localities ranging from Cretaceous to Pliocene. This is the first record of the presence of the species T. cryptomeripsoides and T. cunninghamioides in late Miocene of Yunnan.
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 a 973 program of the Ministry of Science and Technology (Mo ST) of China (20120CB821900)the National Natural Science Foundation of China (grants 41272007, 41030212, 31350110504)+2 种基金the Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botanythe Chinese Academy of Sciences (KLBB 201201 and 2013Y1SA002)part of the NECLIME (Neogene Climate of Eurasia) network
文摘A new species, Tsuga nanfengensis sp.nov.（Pinaceae）, is described on the basis of lignified fossil wood from the late Miocene of the Xianfeng Basin, central Yunnan, southwestern China.Detailed observation of the fossil wood specimens show the following characteristics： distinct growth rings, absence of resin canals, uniseriate bordered pits in the radial wall of tracheids, ray tracheids and piceoid and cupressoid cross-field pits.These features indicate similarities to the wood of extant Tsuga canadensis, T.chinensis, and T.dumosa.According to the fossil record, Tsuga was present in Xundian County during the Miocene.Today Tsuga is drought intolerant, preferring wet conditions with no extant species growing naturally in Xundian County.The presence of Tsuga in the Miocene of Xundian County indicates a humid climate consistent with previous palaeoclimatic reconstructions showing a wetter and probably shorter dry season in the Miocene, relative to the present day.Therefore, the change in the local climate such as increasing aridity through the Miocene might explain the local extinction of Tsuga from central Yunnan.
基金supported by the National Natural Foundation of China(No.40872149,40472100 and 40930419)
文摘The uplift of the Ailao Shan-Diancang Shan （ASDS） along the Ailao Shan-Red River （ASRR） shear zone is an important geological event in the southeastern margin of Qinghai-Tibet Plateau tectonic domain in the Late Cenozoic, and it preserves important information on the structures, exhumationai history and tectonic evolution of the ASRR shear zone. The uplift structural mode and uplift timing of the ASDS is currently an important scientific topic for understanding the ASDS formation and late stage movements and evolution of the ASRR shear zone. The formation of the ASDS has been widely considered to be the consequence of the strike-slip movements of the ASRR shear zone. However, the shaping of geomorphic units is generally direct results of the latest tectonic activities. In this study, we investigated the timing and uplift structural mechanism of the ASDS and provided the following lines of supportive evidence. Firstly, the primary tectonic foliation of the ASDS shows significant characteristic variations, with steeply dipping tectonic foliation developed on the east side of the ASDS and the relatively horizontal foliation on the west side. Secondly, from northeast to southwest direction, the deformation and metamorphism gradually weakened and this zone can be further divided into three different metamorphic degree belts. Thirdly, the contact relationship between the ASDS and the Chuxiong basin-Erhai lake is a normal fault contact which can be found on the east side of the ASDS. 40^Ar/^39 Argeochronology suggests that the Diancang Shan had experienced a fast cooling event during 3-4 Ma. The apatite fission track testing method gives the age of 6.6-10.7 Ma in the Diancang Shan and 4.6-8.4 Ma in the Ailao Shan, respectively. Therefore the uplift of the ASDS can be explained by tilted block mode in which the east side was uplifted much higher than the west side, and it is not main reason of the shearing movements of the ASRR shear zone. The most recent uplift stages of the ASDS happened in the Pliocene （3-4 Ma） and Late Miocene （6-10 Ma）.
基金supported by the National Natural Science Foundation of China(Nos.41172021,41302009)the Foundation of the State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,CAS(No.173126)the Fundamental Research Funds for the Central Universities of China(No.lzujbky-2017-74)
文摘Albizzia is a leguminous genus belonging to the subfamily Mimosoideae with approximately 150 modern species, widely distributed in the tropical and subtropical regions of Asia, Africa, Australia and America. Among them, 17 species are mainly distributed in southern and southwestern China. Abundant fossils of the subfamily Mimosoideae, including leaves, pods, flowers and wood, have been reported from the Cretaceous and Paleogene strata of the Northern Hemisphere. However, Neogene records of Mimosoideae are relatively scarce. In this study, fossil pods and leaves belonging to the genus Aibizzia from the Bangmai Formation of Yunnan, China were described. They were assigned to three species, including Albizzia scalpeUiformis Guo, Li and Xie Emended, Albizzia cf. kalkora （Roxb.） Prain and Albizzia sp. The occurrence of Albizzia fossils from Lincang not only gives important information on the Neogene plant diversity from Yunnan--a worldwide famous biological hotspot--but also provides additional evidence for its phytogeographic history.
基金granted by the National Natural Science Foundation of China (Grant No. 41772381)the Chinese Academy of Geological Sciences Research Fund (Grant Nos. YYWF201511 and DZLXJK201710)the Geological Investigation Project of China Geological Survey (Grant Nos. 121201234000160014, 12120113006100, 121201104000150009 and DD20160083)
文摘The Xining basin is located in the northeastern margin of the Qinghai-Tibet Plateau. It is a rift basin formed in Mesozoic and Cenozoic and structurally belongs to the intersection of Kunlun and Qilian Mountains. Cenozoic fluvial and lacustrine sedimentary strata are continuous in the Xining basin, with a thickness of more than 800 m, completely recording the deformation uplifting, weathering and denudation history and climate change process of the northeastern plateau. Currently, early Miocene Xijia fauna, early Middle Miocene Danshuilu fauna and late Middle Miocene Diaogou fauna are discovered in the Xining basin, which provide an important basis for the stratigraphic correlation of the Cenozoic strata in the Xining basin. However, in the next few decades, there are no reports about the large mammal fossils in the Xining basin, especially about late Miocene fauna. The author discovered a large amount of mammal fossils in the Neogene sedimentary strata in Huzhu area, Xining basin. According to the identification results of the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, these fossils mainly included Hipparion dongxiangense, Chilotherium sp., Parelasmotherium sp., Stephanocemas sp. and Kubanochoerus sp. and their age was early Late Miocene. Since the discovery of this set of fossils directly filled the blank that there were no large mammal fossils in the Xining basin in Late Miocene, it was very important for studying the magnetic stratigraphic chronology of fossil-forming strata and establishing the paleomagnetic chronology scale plate of mammal fossils. In this paper, the paleomagnetic data of the fossil-forming stratigraphic profile, Banyan profile, were measured and the paleomagnetic records were collected through high density sampling, and finally the paleomagnetic polarity column of the profile was established. The results showed that five positive and five negative polarity segments were recorded in Banyan profile, which corresponded well to the polarity between C3 Br.1 n-C4 n.2 n in the standard polarity column. The age of profile top was about 7.25 Ma and profile bottom was about 8.4 Ma, with an age range of 1.15 Ma. The mammal fossils discovered this time were exposed between positive and negative polarities N5 and R5 at the bottom of the profile, corresponding to C4 r.1 r at negative polarity and C4 n.2 n at positive polarity in the standard polarity column. The age of mammal fossils was about 8.3 Ma. The paleomagnetic chronology of the strata and paleontological fossils determined the absolute age of late Miocene mammal fossils and expanded the upper age of late Miocene Xianshuihe Formation(N1 xn) in the Xining basin, which had provided new basic data for further studying the stratigraphic deposition and correlation of late Cenozoic strata and regional environmental evolution.
基金financially supported by the Chinese Academy of Geological Sciences Research Fund(Grant Nos.YYWF201511,DZLXJK201710,DZLXJK201405)the Geological Investigation Project of China Geological Survey(Grant Nos.12120113006100, 121201234000160014-4,121201101000150013)
文摘Objective Xining basin is located in the northeastern Qinghai- Tibetan Plateau, which tectonic location belongs to a junction of the Kunlun and Qilian mountains. The southern, northern and western parts of the basin are restricted by the Laji, Daban and Riyue mountains fault zones, and go eastward into the Longzhong basin in Gansu Province. A succession of Cenozoic lacustrine sedimentary strata has been well developed in the Xining basin, with sediments over 800 m thick.
文摘The ancient Mediterranean was once dried up around6~5.3million years ago.It is a landmark event,which had great impact on global environment and climate.However,few references are available in the literatures on this topic,
基金supported by National Nature Science Foundation of China (Grant No.41872017)the Fundamental Research Funds for the Central Universities,CHD (No.300102272206)the Natural Science Basic Research Program in Shaanxi Province of China (Grant No.2023-JC-YB-223)。
文摘Abundant plant fossils were found in the Upper Miocene Shengxian Formation,eastern Zhejiang Province,China,among which Trapa belongs to a dominant population.The fossil fruits of Trapa were well preserved with abundant details.However,due to compaction during fossilization,Trapa fruits were often flattened,leading to the loss of some characteristic features.Thereby,a bias in taxonomic and phylogenetic studies would occur when such studies were based on these fruit fossils.In this study,we present the first quantitative three-dimensional reconstruction of compressed Trapa fruit fossils to restore their original morphology prior to burial.This approach provides a novel perspective for the identification and classification of compressed fruit fossils.The three-dimensional reconstruction of Trapa fruit fossils enabled accurate comparisons with extant species.We subsequently identified it as a new species,named Trapa radiatiformis L.Xiao sp.nov.,revealing differences from previously known taxa of Trapa.Importantly,our comparison suggests that the long lower horns and residual stalk may represent inherent characteristics of early Trapa fruits.However,these traits gradually degenerated during fruit evolution,resulting in morphological simplification during geological time.T.radiatiformis with primitive features exhibits good resemblance to Trapa natans fruit characteristics,which means it may be an ancestor of T.natans.We summarize the palaeogeographic distribution of fossil Trapa using previously published literature and demonstrate that the genus was mostprosperous in the Miocene and exhibited the same distribution as that at present.Additionally,through detailed morphological comparisons between Trapa and Hemitrapa fruits,along with phylogenetic analysis within the Primotrapa genus itself,we propose a homology between Trapa and Hemitrapa,suggesting that they could have a common ancestor.
文摘TheÇorakyerler fossil locality in Anatolia reveals unique faunal elements.This study introduces Hystrix kayae sp.nov.,a new Late Miocene porcupine initially classified as Hystrix sp.Yavuz et al.,2018.This finding expands our knowledge of Late Miocene Anatolian porcupines,bringing the total number of known species to three.H.kayae sp.nov.is larger than Hystrix aryanensis and exhibits greater upper cheek tooth crown height.Its cheek tooth morphology differs from Hystrix depereti,and it possesses distinctive U-shaped choanae unlike Hystrix primigenia.TheÇorakyerler locality may predate sites with H.aryanensis and H.primigenia but aligns temporally with Hystrix parvae localities.This study enhances our understanding of Late Miocene porcupine diversity in Anatolia,emphasizing the importance ofÇorakyerler in unraveling the evolutionary history of these fascinating mammals.
基金supported by the National Natural Science Foundation of China(31300187,31300188)the Natural Science Foundation of Yunnan Province(2010CC010)
文摘Euryale （Nymphaeaceae） is a monotypic genus distributed in eastern Asia, but fossils in its native distribu- tion are sparse as compared to Europe where the genus has disappeared. Here, we describe a new fossil species, Euryale yunnanensis sp. nov., from the late Miocene Zhaotong Basin in southwestern China on the basis of seed remains. Char- acteristics including an ellipsoidal to almost spherical shape, a smooth surface, a germination cap that covers the micro- pyle, the separation of the hilum and germination cap （mi- cropyle）, elliptic testa surface cells with undulate margins and thickened cell walls collectively indicate a close affinity with the genus Euryale in Nymphaeaceae. Comparisons of seed morphology and anatomy demonstrate that the newly described fossil species differs from modem and other fossil species of Euryale and thus verify the assignment to a new fossil species. As the modem Euryale is an aquatic plant, preferably living in swamps and lakes with shallow and stable water, we hypothesize that a lake and/or swamp environment with shallow water was present near Shui- tangba in the Zhaotong Basin, where the Shuitangba homi- noid lived during the late Miocene. This inference is generally consistent with paleoenvironmental data extracted from avian, fish, frog, turtle and crocodile fossils, as well as from aquatic pollen. The fossil history suggests a compara- tively recent （Miocene） emergence of Euryale, which is roughly in agreement with the divergence time inferred from the molecular information.
基金funded by the National Science and Technology Major Project(Exploration Technologies for Offshore Hidden Oil/Gas)(Project No.:2016ZX05024003-003)
文摘The Huanghekou Sag is located at the southeast part of the Bohai Bay Basin, northern China. Large-scale shallow lake delta developed in the Neogene provided suitable geological conditions for the formation of a subtle oil-gas reservoir in this area. The key for analyzing sandstone reservoir and sedimentary facies is by using seismic attributes(amplitude) to establish the relationship between lithology combination and seismic attributes. The lower unit of Late Miocene Minghuazhen Formation at the BZ34 block in the Huanghekou Sag was subdivided into 10 parasequence sets(PSS). Thicker sandstones mainly occurred in PSS1 and PSS10, whereas thin sandstones are mostly observed within other parasequence sets. This study presents statistics and analyses of lithology, i.e., statistics of root-meansquare(RMS) amplitude and lithology of well locations in different parasequence sets of the study area,as well as 1-D forward seismic models of 7 types of lithology combinations, the establishment of a spatial distribution of 2-D sandbody, forward seismic models etc. Our study indicates that high amplitude peaks correspond to thicker sandbodies, while low amplitude indicates non-development of sandbodies(generally less than 2 m), and medium amplitude agrees well with large sets of mudstones interbedded with medium and thinner sandstones. Different sand-mudstone combinations genetically reflect a combination of multiple micro-facies, therefore, amplitude features can predict sandbodies as well as facies characteristics.
基金the National Natural Science Foundation of China (No. 31170206)the National Financial Fund of China (Project "collection and purchase of specimen of Geological heritage", No. 1211311381001)National International Science and Technology Cooperation Program (2009DFA32210)
文摘The Upper Miocene Xiaohe Formation of the Yuanmou Basin in Yunnan Pro- vince, southwestern China, is famous for its hominoid fauna and is important for studying the Late Cenozoic human and mammal evolution. Abundant fossil wood was found associated with this fauna, which provided important evidence for palaeoenvironmental reconstruction of the basin. Among the fossil wood, two different taxa have been identified namely, Quercoxylon sp. （Fagaceae） and Pterocarya sp. （Juglandaceae）. Based on the habitats of their Nearest Living Relatives （NRLs）, it is suggested that upland subtropical evergreen broad-leaved forest dominated by QuercuslLithocarpus was common around the basin, while a lowland deciduous broad-leaved forest dominated by Pterocarya was present on the river bank of the basin during the Late Miocene.
基金This paper is included in the projects CGL2012-38087,CGL2009-12703-C03-03,EHU 10/32(Universidad del País Vasco UPV/EHU)and CGL2012-38358.
文摘The vertebrate fossil record from the Balearic Islands(western Mediterranean)has improved considerably over the past decade,especially in Mallorca and Menorca.In Menorca,the Pliocene terrestrial fauna was updated by the discovery and description of the large-sized leporid Nuralagus,several reptiles and an amphibian.In Mal-lorca,paleontological exploration yielded 2 deposits with a Late Miocene/Early Pliocene chronology,Calóden Rafelino(CdR)and Na Burguesa-1(NB-1).So far,4 new mammalian taxa and 2 new reptiles have been iden-tified for the CdR deposit,whereas the faunal assemblage from the recently discovered deposit(Apr 2012)of NB-1 is currently composed of,at least,6 terrestrial mammals,8 reptiles and an amphibian.Its faunal composi-tion and some primitive characteristics of the obtained taxa suggest that the chronology of this deposit is slight-ly earlier than the CdR.The terrestrial vertebrates recorded in these 2 Mallorcan deposits are changing the view of the paleofaunal assemblage previously known for the Plio-Pleistocene of the island.Morphological charac-teristics displayed by some of the taxa suggest that these faunas would be at the beginning of an isolated evo-lution.In this paper we present a preliminary report on the fossils recovered from the NB-1 deposit,as well as some unpublished data from CdR,and we analyze the whole fauna from both Mallorcan deposits,focusing on taxonomical and paleobiogeographical aspects.
基金funded by the Foundation of the Geological Survey of China(No.1212011121261)the National Natural Science Youth Foundation of China(Nos.41702118,41702363 and41602037)the China Postdoctoral Science Foundation(Nos.2014M552109 and 2015M582301)
文摘With a thick sequence of early Eocene to Pleistocene terrestrial records, the Qaidam Basin on the northern Tibetan Plateau provides an important sedimentary archive for understanding the paleoenvironmental evolution of the northeast Tibetan Plateau. In this study, specimens of fossil fish remains are collected from the late Middle Miocene（Serravallian, -12 Ma） of the middle member of the Shang Youshashan Formation, Dahonggou（DHG） section, in the northern Qaidam Basin. Based on a systematic study of these materials, the remains have assigned to Cyprinidae, with typical pharyngeal teeth and dorsal fin spines with serrations on the posterior edge. Our discovery improves understanding of the cyprinid fish distribution characteristics in the Qaidam Basin during the Cenozoic. Cooccurrences of terrestrial brackish ostracod species Cyprideis and long chain alkenonesin the layer indicate that the studied cyprinid fish lived in a generally large brackish to saline water body during the late middle Miocene（Serravallian）, when the climate of Qaidam Basin was still not sufficiently dry to form an extreme saline water lake.
基金DST-SERB,GOI,New Delhi,India(File no.CRG/2020/001303)for their financial assistance。
文摘Equisetum(Equisetaceae)has long been a focus of attention for botanists and palaeontologists because,given its extensive and well-documented fossil record,it is considered the oldest extant vascular plant and a key element in understanding vascular plant evolution.However,to date,no authentic fossil evidence of Equisetum has been found from the Indian Cenozoic.Here,we describe a new fossil species,namely,E.siwalikum sp.nov.,recovered from the middle Siwalik(Late Miocene)sediments of Himachal Pradesh,western Himalaya.We identified fossil specimens based on morphological and epidermal characters.In addition,X-Ray diffraction(XRD)analysis was used to determine the mineral composition of compressed stems of Equisetum.The close affinity of our recovered Siwalik fossils to Equisetum is supported by the presence of both macromorphological and epidermal characters.Because Equisetum generally grows in wet conditions around water reservoirs,our findings indicate that the fossil locality was humid and surrounded by swamp and lowland regions during deposition.Ample fossil evidence indicates that this sphenopsid once existed in the western Himalaya during the Siwalik period.However,at present Equisetum is confined to a particular area of our fossil locality,probably a consequence of severe environmental changes coupled with competition from opportunistic angiosperms.Our discovery of Equisetum fossils in appreciable numbers from the Siwalik sediments of the Himachal Himalayas is unique and constitutes the first reliable recognition of Equisetum from the Indian Cenozoic.
基金supported by the National Natural Science Foundation of China(Grant No.42488201)the Strategy Priority Research Program(Category B)of Chinese Academy of Sciences(Grant No.XDB0710000)。
文摘The Liupan Mountains,one of the important mountain ranges in western China,are located on the boundary between the northeastern Tibetan Plateau and the Ordos Block.The uplift history of the Liupan Mountains remains controversial.Loess deposits are good tracers of regional tectonic and geomorphic changes,because loess is sensitive to erosion and the formation and preservation of loess requires relatively flat highlands and relatively stable tectonic environments.We investigated the distribution of Neogene loess deposits on the western piedmont of the Liupan Mountains and examined a near-continuous loess section(Nanping section)on the piedmont alluvial highlands.Correlation of magnetic susceptibility stratigraphy with the QA-ⅠMiocene loess sequence dates this 56-m section covering the interval from~8.1 to 6.2 Ma.The lower boundary age of this section,together with previously reported Zhuanglang red clay(sand-gravel layers with intercalated loess during~9–8 Ma and near-continuous loess during~8–4.8 Ma)and Chaona red clay(~8.1–2.58 Ma),indicates that the Liupan Mountains were uplifted in the late Miocene(~9–8 Ma)and basically formed by~8 Ma,attesting to no intense mountain building since that time.In addition,based on the information from the Zhuanglang core and the QA-Ⅰsection,we infer that sizable parts of the Liupan Mountains were uplifted during the late Oligocene–early Miocene and did not experience intense uplift during~22–9 Ma.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDB26000000 and XDA20070203)the National Natural Science Foundation of China(Grant Nos.42102001,41430102,41872001,41872005 and 41772018)+2 种基金Key Frontier Science Research Program of the Chinese Academy of Sciences(Grant Nos.QYZDY-SSW-DQC-22 and GJHZ1885)China Scholarship CouncilFrick Fund,Division of Vertebrate Paleontology,AMNH.
文摘Mammals have high dispersal ability,and many lineages can spread across the continents when a landbridge appears.Here,we summarize the dispersal of mammals between the Old and New World at the end of the Miocene.Our analysis suggested that the three phases of dispersal represented the largest dispersal tide during the Neogene,and the direction of dispersal is dominated by being from the Old to New World.Judging from the components that crossed the dispersal corridor,the Arctic environment near the Beringia corridor in the first phase(~7.5 Ma)is a mixed environment,and in the second phase(~6.5 Ma)is an open environment,and in the third phase(~5.8 Ma and continue to the Pliocene)is a wooded(closed)environment.A clear trend of eastern Asian humidification driven by Asian monsoon and the global C4 grassland expansion explain this dispersal pattern.The boost of mammalian dispersals is controlled by the heterogeneity of environmental changes in different continents.
文摘In the last 30 ma, the passive continental margin of South America and the Amazonian basin experienced three periods of major sea level inundation;viz. at around 20 ma, at around 10 ma and at around 3 ma. The establishment of the immense Amazonian rainforest ecosystem covering some 6 million square km can neither have occurred during the periods of high sea level nor at the intermediate periods of arid or semi-arid climatic conditions. Therefore, the origin of the Amazonian rainforest of present-day dimensions must be set at the Late Miocene. The establishment of the Amazonian rainforest implied the withdrawal of enormous quantities of water from the global hydrological cycle. The drastic increase in evaporation leading to the Messinian salinity crisis in the Mediterranean occurred at the same time as the Amazonian rainforest (sensu hodierno) establishment suggesting a causal linkage.
