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Quercus yangyiensis sp. nov. from the Late Pliocene of Baoshan, Yunnan and Its Paleoclimatic Significance 被引量:8
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作者 HE Yuli LI Na +5 位作者 WANG Zixi WANG Haofei YANG Guolin XIAO Liang WU Jingyu SUN Bainian 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第3期738-747,共10页
A new Quercus (Fagaceae) morphospecies is described based on well-preserved fossil leaves.The fossils were collected from Yangyi Formation of the Upper Pliocene at the Yangyi coalmine,Baoshan,western Yunnan,China.De... A new Quercus (Fagaceae) morphospecies is described based on well-preserved fossil leaves.The fossils were collected from Yangyi Formation of the Upper Pliocene at the Yangyi coalmine,Baoshan,western Yunnan,China.Details of the microstructure of mesophyll tissue are preserved because lithification of the fossils was not complete.The fossil laminas possess typical characteristics of Quercus sect.Heterobalanus:quite thick and coriaceous cuticle; secondary veins bifurcating near the margin in the middle and top of the leaf; and upper epidermis with adaxial hypodermis.Based on a detailed morphological and anatomical comparison with all living and fossil species of Quercus sect.Heterobalanus,the fossil leaves prove to be different in their sparse and garland-shaped multicellular trichomes on the lower epidermis,and so it is described as a new species Quercus yangyiensis He,Li et Sun sp.nov.The much sparser trichomes of our fossils compare well with those of living Quercus sect.Heterobalanus and indicate a more humid climate during the deposition of the Yangyi Formation in the Late Pliocene. 展开更多
关键词 PALEOBOTANY fossil leaf cuticle QUERCUS PALEOCLIMATE pliocene YUNNAN
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Terrestrial Mio-Pliocene Boundary in the Linxia Basin,Gansu,China 被引量:7
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作者 DENG Tao HOU Sukuan +3 位作者 SHI Qinqin CHEN Shaokun HE Wen CHEN Shanqin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2011年第2期452-464,共13页
The Lower Pliocene of the Linxia Basin in Gansu Province is one of only a few representative sections for the Early Pliocene sedimentary records in northern China, and even in East Asia. Recently,abundant mammalian fo... The Lower Pliocene of the Linxia Basin in Gansu Province is one of only a few representative sections for the Early Pliocene sedimentary records in northern China, and even in East Asia. Recently,abundant mammalian fossils were found from the base of red clays of the Lower Pliocene Hewangjia Formation at Duikang in Guanghe County within this basin. Previously, the Pliocene mammals were sparsely found in China, and most were collected from fluvial and lacustrine deposits in the eastern Loess Plateau. Mammals from the widely distributed Pliocene Hipparion Red Clay are less in number.The known fossils from Duikang include 20 species and belong to the Shilidun Fauna. Their faunal components are similar to the Early Pliocene Gaozhuang Fauna from Ynshe, Shanxi. On the other hand, some taxa from Duikang have not been found in the Gaozhuang Fauna, are slightly more primitive in evolutionary level, and appeared mainly in the Late Miocene. As a result, the age of the Duikang fossils may be slightly earlier than that of the Gaozhuang Fauna and closer to the lower boundary of the Piiocene. The Duikang fossiliferons bed is 0.8 m above the top of the Late Miocene Linshu Formation, and the first occurrence of the three-toed horse Hipparion pater can be regarded as a biostratigraphical marker of the Miocene/Pliocene boundary. In conclusion, Duikang is an ideal candidate locality to establish as the stratotype of the lower boundary of the Chinese terrestrial Pliocene. 展开更多
关键词 MIOCENE pliocene boundary stratotype mammalian fauna Hipparion Red Clay Linxia Basin
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Structure,Timing,and Mechanism of the Pliocene and Late Miocene Uplift Process of the Ailao Shan-Diancang Shan,SE Tibet,China 被引量:3
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作者 LI Baolong WANG Dandan JI Jianqing 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第4期1084-1101,共18页
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
关键词 Ailao Shan-Diancang Shan tectonic geomorphology apatite fission track method 40^Ar/39^Ar dating tilted block uplift pliocene and Late Miocene
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Paleophytochemical Constituents from the Pliocene Fossil Wood of Pinus Armandii from Longling,Yunnan 被引量:2
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作者 ZHAO Youxing LI Chengsen +2 位作者 YI Tiemei LUO Xiaodong ZHOU Jun 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2008年第6期1146-1151,共6页
Specimens of fossil wood preserved lignified in Pliocene brown coal and identified as Pinus armandii Francher come from an opencast coalmine at Longling in western Yunnan Province, China. Phytochemical investigation o... Specimens of fossil wood preserved lignified in Pliocene brown coal and identified as Pinus armandii Francher come from an opencast coalmine at Longling in western Yunnan Province, China. Phytochemical investigation of the fossil wood isolated using liquid column chromatography seven compounds (1-7) including a new fluorene derivative named 11,11-dimethyl-11H-benzo[b]fluorene. A further 28 volatiles were detected by gas chromatography-mass spectrometry (GC-MS). Spectroscopic investigation methods, including MS and 1D and 2D-NMR techniques elucidated the structure of the seven compounds. Two types of natural products, isopimara and stilbene commonly occuring in extant and Pliocene fossil P. armandii indicate phytochemical fidelity during burial under certain circumstances in sediments. Discovery of stilbenes that can inhibit the activities of wood-destroying fungi in the Pliocene P. armandii prompts the assumption that the chemical preservation of this Pliocene fossil wood of P. armandii in brown coal might contribute to the presence of inner natural inhibitors against wood-destroying fungi. 展开更多
关键词 pliocene wood constituents STILBENOIDS PHYTOCHEMISTRY Pinus armandii
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Geochemistry and provenance of the lower-middle pliocene cheleken formation,Iran 被引量:1
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作者 Houshang Mehrabi Seyed Mohammad Zamanzadeh +4 位作者 Abdolhossein Amini Vahid Tavakoli Freshteh Sajjadi Seyede Sepideh Mirrabie Behzad Soltani 《Acta Geochimica》 EI CAS CSCD 2021年第5期787-805,共19页
In the present study,the Lower-Middle Pliocene Cheleken Formation in the south of Ghaemshahr city was studied to determine the provenance of the comprising sediments,paleoclimatic conditions,and tectonic setting of th... In the present study,the Lower-Middle Pliocene Cheleken Formation in the south of Ghaemshahr city was studied to determine the provenance of the comprising sediments,paleoclimatic conditions,and tectonic setting of the rocks.Petrographic and geochemical analyses of major and minor elements of the samples were used for this purpose.This Formation is composed of three major facies including conglomerate,fine sandstone,and mudstone.The source formations which were recognized to be supplying sediments to the Cheleken Formation depositional basin include Lalun,Ziarat,Tizkuh,Dalichai,and Cretaceous formations.According to the discrimination diagrams and other ratios for minor elements of the studied samples,a complex of felsic to intermediate igneous rocks in the source region was deciphered.The depositional environment of the rocks experienced humid and semi-arid climatic conditions during deposition.According to the CIW index,the samples underwent a high level of weathering(97%)in the source area or during transportation.From a tectonic point of view,the Cheleken Formation was deposited in an Active Continental Margin setting. 展开更多
关键词 GEOCHEMISTRY PROVENANCE Cheleken formation pliocene Caspian sea
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Sea-Surface Dynamics Changes in the Subpolar North Atlantic Ocean (IODP Site U1314) during Late Pliocene Climate Transition Based on Calcareous Nannofossil Observation 被引量:1
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作者 Resti Samyati Jatiningrum Tokiyuki Sato 《Open Journal of Geology》 2017年第10期1538-1551,共14页
Calcareous nannofossils were observed to reconstruct the surface water conditions during late Pliocene climate transition (2.55 to 2.88 Ma) from the southern Gardar Drift, in the subpolar North Atlantic IODP Site U131... Calcareous nannofossils were observed to reconstruct the surface water conditions during late Pliocene climate transition (2.55 to 2.88 Ma) from the southern Gardar Drift, in the subpolar North Atlantic IODP Site U1314 (56&#176;21.9’1N, 27&#176;53.3’W). A total of 24 species from 14 genera were identified by polarizing microscope observation. The coccolith assemblages are dominated by species belonging to genus Reticulofenestra with different (size-defined) morphotype. Hence, changes in paleoceanographic condition are shown by the size variation of Reticulofenstraspecimens. Before ~2.76 Ma, the studied interval is characterized by the presence of an abundant larger Reticulofenstra group. It indicates warm oligotrophic and stable surface waters. At ~2.76 Ma the abundance of large Reticulofenstra decreased abruptly and alternated with small Reticulofenstra, suggesting collapse of sea surface stability with strong mixing condition. This event coeval with the final closure of the Central American Seaway (CAS) and the onset of intensified North Hemisphere Glaciation (NHG). Subsequently, the size variation of Reticulofenestra specimens exhibits a sequential pattern that is somewhere consistent with the interglacial-glacial cycle. The pattern begins with a gradual increase in size upward during interglacial suggesting warm oligotrophic and stable condition, and ends with an abrupt decrease in coccolith size during glacial suggesting eutrophic or strong mixing condition and destabilized sea surface waters. 展开更多
关键词 Late pliocene SEA-SURFACE Waters Conditions CALCAREOUS NANNOFOSSIL Subpolar North ATLANTIC
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Pliocene hyperpycnal flow and its sedimentary pattern in D block of Rakhine Basin in Bay of Bengal 被引量:1
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作者 ZHOU Lihong SUN Zhihua +7 位作者 TANG Ge XIAO Dunqing CAI Zheng WANG Haiqiang SU Junqing HUA Shuangjun GE Wei CHEN Changwei 《Petroleum Exploration and Development》 2020年第2期318-330,共13页
Based on core,logging,lab test and seismic data,sedimentary characteristics and pattern of marine hyperpycnal flow,the distribution rules of hyperpycnal flow reservoir,prediction method of favorable hyperpycnal flow r... Based on core,logging,lab test and seismic data,sedimentary characteristics and pattern of marine hyperpycnal flow,the distribution rules of hyperpycnal flow reservoir,prediction method of favorable hyperpycnal flow reservoir zones,hydrocarbon accumulation model in hyperpycnal flow reservoir in D block of Bay of Bengal were investigated,and the favorable exploration zone and well sites were predicted.Pliocene in D block has typical hyperpycnal flow sediment,which is a set of fine-medium sandstone held between thick layers of marine mudstone and features a series of reverse grading unit and normal grading unit pairs.The hyperpycnal flow sediment appears as heavily jagged box shape,bell shape and tongue shape facies on log curves with linear gradient,and corresponds to multiple phases of deep channels on the seismic section and high sinuous channel on stratal slices.The sedimentary bodies formed by a single phase hyperpycnal flow which include five types of microfacies,namely,supply channel(valley),channel complex,branch channel,levee and sheet sand.The hyperpycnal flow sediments appear in multiple branches,multiple generations and stages in space,forming high-quality reservoirs in strips on the plane and superposition vertically,with fairly good physical properties.The channel complex sandstone,with large thickness,coarse particle size and good physical properties,is the most favorable exploration facies.Based on the guidance of the sedimentary model,distribution of the channel complex microfacies was delineated in detail by seismic reflection structure analysis,spectrum waveform characteristic analysis,slice and attribute fusion,and combined with the structural feature analysis,the favorable drilling zone was sorted out,effectively guiding the exploration deployment of the block. 展开更多
关键词 Bay of Bengal Rakhine Basin pliocene gravity flow hyperpycnal flow sedimentary pattern RESERVOIR oil and gas exploration
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Late Pliocene diversity and distribution of Drynaria(Polypodiaceae) in western Yunnan explained by forest vegetation and humid climates 被引量:1
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作者 Yong-Jiang Huang Tao Su Zhe-Kun Zhou 《Plant Diversity》 SCIE CAS CSCD 北大核心 2016年第4期194-200,共7页
The palaeodiversity of flowering plants in Yunnan has been extensively interpreted from both a molecular and fossil perspective. However, for cryptogamic plants such as ferns, the palaeodiversity remains poorly known.... The palaeodiversity of flowering plants in Yunnan has been extensively interpreted from both a molecular and fossil perspective. However, for cryptogamic plants such as ferns, the palaeodiversity remains poorly known. In this study, we describe a new ferny fossil taxon, Drynaria lanpingensis sp. nov. Huang,Su et Zhou(Polypodiaceae), from the late Pliocene of northwestern Yunnan based on fragmentary frond and pinna with in situ spores. The frond is pinnatifid and the pinnae are entirely margined. The sori are arranged in one row on each side of the primary vein. The spores have a semicircular to bean-shaped equatorial view and a tuberculate surface. Taken together with previously described fossils, there are now representatives of three known fossil taxa of Drynaria from the late Pliocene of western Yunnan.These finds suggest that Drynaria diversity was considerable in the region at that time. As Drynaria is a shade-tolerant plant, growing preferably in wet conditions in the understory of forests, its extensive existence may indicate forest vegetation and humid climates in western Yunnan during the late Pliocene.This is in line with results from floristic investigations and palaeoclimatic reconstructions based on fossil floras. 展开更多
关键词 Biodiversity Fern Drynaria In sire spore Late pliocene Yunnan
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CHARACTERISTICS OF ALKALINE VOLCANIC ROCKS OF PLIOCENE IN THE WESTERN PART OF HONGHE FAULT ZONE
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作者 Wang Guozhi,Huang Yongjian,Ma Renze,Wang Chengshan 《地学前缘》 EI CAS CSCD 2000年第S1期270-271,共2页
A set of pull\|apart basins were formed along the Weixi—Qiaohou right\|lateral slip shear zone of the western part of Honghe fault zone during the period from Miocene to Quaternary.A rock suite of alkaline basalt\|tr... A set of pull\|apart basins were formed along the Weixi—Qiaohou right\|lateral slip shear zone of the western part of Honghe fault zone during the period from Miocene to Quaternary.A rock suite of alkaline basalt\|trachyte\|leucite phonolite is distributed in the Pliocene basin developed in the middle and northern parts of the fault. The location of these rocks and the features of the basin indicate the close relationship between the rock suite and the strike\|slipping.. The sedimentological and chronological evidences prove that Dianxi plateau uplifted quickly in the Pliocene. We can get the information about the plutonic process of the uplift of the plateau from this alkaline rock association. There are mainly olivine\|pyroxene\|trachyandesite and biotite\|trachyte in the rock association. The rocks are often of porphyritic texture and block or semi\|directional flowage structure while the matrix is of trachytic or microcrystalline texture. The phanerocrysts are diopsidic augite, rimpylite, biotite and perthite (olivine sometimes can be seen). The matrix are made up of alkaline feldspar microcrystalline (30%~50%), short\|grained diopside (10%~15%), light\|colored volcanic glass (0~15%) and some magnetite, while feldspar microcrystalline in some rocks are arranged directionally. And there are sharp\|edged or round pyroxenite enclaves and hemicrystalline of short grained sinaite, biotite sinaite and felsic breccia in the trachyte, with good demarcation line. The pyroxenite enclaves in the trachyte are of different size, and the size of the biggest ones are 10cm or so with the characteristic of plastic yield flowing. Sinaite hemicrystalline may come from the older intrusions of Pliocene and Eocene epoch. 展开更多
关键词 Honghe fault zone pliocene TRACHYTE strike\|slip UPLIFT
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A New Species of Rhodoleia(Hamamelidaceae) from the Upper Pliocene of West Yunnan, China and Comments on Phytogeography and Insect Herbivory
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作者 WU Jingyu ZHAO Zhenrui +4 位作者 LI Qijia LIU Yusheng(Christopher) XIE Sanping DING Suting SUN Bainian 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2015年第5期1440-1452,共13页
In Europe, fossil fruits and seeds of Rhodoleia(Hamamelidaceae) have been described from the Upper Cretaceous to the Miocene, whereas no fossil record of Rhodoleia has been reported in Asia, where the modern species... In Europe, fossil fruits and seeds of Rhodoleia(Hamamelidaceae) have been described from the Upper Cretaceous to the Miocene, whereas no fossil record of Rhodoleia has been reported in Asia, where the modern species occur.Herein, 21 fossil leaves identified as Rhodoleia tengchongensis sp.nov.are described from the Upper Pliocene of Tengchong County, Yunnan Province, Southwest China.The fossils exhibit elliptic lamina with entire margins, simple brochidodromous major secondary veins, mixed percurrent intercostal tertiary veins, and looped exterior tertiaries.The leaf cuticle is characterized by pentagonal or hexagonal cells, stellate multicellular trichomes, and paracytic stomata.The combination of leaf architecture and cuticular characteristics suggests that the fossil leaves should be classified into the genus Rhodoleia.The fossil distributions indicate that the genus Rhodoleia might originate from Central Europe, and that migrated to Asia prior to the Late Pliocene.Additionally, insect damage is investigated, and different types of damage, such as hole feeding, margin feeding, surface feeding, and galling, are observed on the thirteen fossil leaves.Based on the damage frequencies for the fossil and extant leaves, the specific feeding behavior of insects on Rhodoleia trees appears to have been established as early as the Late Pliocene.The high occurrence of Rhodoleia insect herbivory may attract the insect-foraging birds, thereby increasing the probability of pollination. 展开更多
关键词 Rhodoleia leaf cuticle phytogeography insect herbivory pliocene Yunnan Province
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Geochemistry and Petrogenesis of Basaltic Rocks and Enclosed Xenoliths from the Ghab Pliocene Volcanic Field in Northwestern Syria
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作者 Ali T. Al-Mishwat Safwan S. Dawod 《International Journal of Geosciences》 2021年第8期667-688,共22页
Basaltic rocks and their content of ultramaf</span><span style="font-family:Verdana;">i</span><span style="font-family:Verdana;">c xenoliths are common in the Ghab Pliocene ... Basaltic rocks and their content of ultramaf</span><span style="font-family:Verdana;">i</span><span style="font-family:Verdana;">c xenoliths are common in the Ghab Pliocene Volcanic Field in northwestern Syria in the form of lava flows, cinder cones and pyroclastic deposits. The rocks occur within the Ghab pull-</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">apart graben that formed by sinister strike slip faults within the zone that defines the boundary between the African and the Arabian plates. Three petrographic types occur: basanite, olivine basalt and more commonly alkali olivine basalt. The peridotite xenoliths are spinel lherzolite and harzburgit</span><span style="font-family:Verdana;">e.</span><span style="font-family:Verdana;"> Geochemical analysis indicates that the basalts are mostly alkaline to subalkaline. </span><span style="font-family:Verdana;">A distinctive feature of these rocks is the narrow compositional var</span><span style="font-family:Verdana;">iations in the content of most major oxides and minor elements, SiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> (44.33 - 46.43 wt%) and MgO (4.01 - 8.28 wt%). Some of the refractory and high field strength elements and incompatible minor elements in the basalts are relatively high (Cr average = 303 ppm and Ni average = 185 ppm) compared with </span><span style="font-family:Verdana;">their content in average basalts. These geochemical characteristics reflect cr</span><span style="font-family:Verdana;">ystallization of the Ghab basalts from pristine and primary magmas that have experienced minimal fractional crystallization and crustal contamination. Similarly, chemical compositions of the ultramafic xenoliths vary within a restricted geochemical range. They are compatible with the generation of these rocks from partial melting of a primitive mantle pyrolite to yield the xeno</span><span style="font-family:Verdana;">liths</span><span style="font-family:Verdana;">.</span><span style="font-family:Verdana;"> These magmatic processes operated during the Pliocene in a regional </span><span style="font-family:Verdana;">transtensional stress environment attending the development of the Dead Sea Rift. 展开更多
关键词 BASALT XENOLITH Ghab SYRIA pliocene
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Identification of Greigite in the Pliocene Sediments of Qinghai Lake and Its Geological Significance 被引量:1
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作者 FU Chaofeng Jan BLOEMENDAL +2 位作者 QIANG Xiaoke Mimi J.HILL AN Zhisheng 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2016年第6期2261-2262,共2页
The Qinghai Lake in North China is the largest interior plateau lake in Central Asia, and is sensitive to climate change and the environmental effects of Tibetan Plateau uplift. An almost continuous 626 m long sedimen... The Qinghai Lake in North China is the largest interior plateau lake in Central Asia, and is sensitive to climate change and the environmental effects of Tibetan Plateau uplift. An almost continuous 626 m long sediment core was drilled in an in-filled part of the southern lake basin in the Scientific Drilling at Qinghai Lake. 展开更多
关键词 In LAKE Identification of Greigite in the pliocene Sediments of Qinghai Lake and Its Geological Significance
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Latest Neogene Paleoclimate Variation in Yunnan,Southwest China,Revealed by Fossil Leaf Physiognomy 被引量:1
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作者 DAI Jing CHEN Weizhao +1 位作者 HUANG Liang ZHANG Yi’nan 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2023年第4期1268-1281,共14页
Yunnan Province,located in the southeastern margin of the Tibetan Plateau,can provide important information on how climate change was influenced by global cooling.However,its variation patterns in temperature and prec... Yunnan Province,located in the southeastern margin of the Tibetan Plateau,can provide important information on how climate change was influenced by global cooling.However,its variation patterns in temperature and precipitation during the latest Neogene are not well-understood.Based on the 357 specimens assigned to 31 morphotypes of plant fossils from the upper Pliocene Ciying Formation in Yiliang County,Yunnan Province,Southwest China,paleoclimate was estimated by Leaf Margin Analysis and Climate Leaf Analysis Multivariate Program.Compared to the present climate,the mean annual temperature and coldest month temperature have not changed significantly since the late Pliocene,whereas the warmest month temperature has decreased significantly.All precipitation-related parameters have decreased,particularly winter precipitation.Combined with the climatic data of the same period in other areas of Yunnan,the western and eastern Yunnan has shown a similar pattern in temperature variation since the late Pliocene except for central Yunnan;whereas the variation in precipitation does not follow a common law except for a consistent decrease in winter precipitation.Our study reinforced the fact that under the background of global cooling and intensified monsoon systems,different areas of Yunnan exhibit different climatic responses to these changes because of their topographic heterogeneities. 展开更多
关键词 plant fossil paleoclimate reconstruction MONSOON pliocene YUNNAN
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Fission Track Geochronology of Xiaonanchuan Pluton and the Morphotectonic Evolution of Eastern Kunlun since Late Miocene 被引量:6
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作者 王岸 王国灿 +1 位作者 谢德凡 刘德民 《Journal of China University of Geosciences》 SCIE CSCD 2006年第4期302-309,共8页
Apatite fission track (AFT) thermochronology of seven samples from the Xiaonanchuan (小南川) pluton in the Kunlun (昆仑) pass area was carried out, for the purpose of determining the timing of cooling and the re... Apatite fission track (AFT) thermochronology of seven samples from the Xiaonanchuan (小南川) pluton in the Kunlun (昆仑) pass area was carried out, for the purpose of determining the timing of cooling and the relation between the exhumation and the morphotectonic processes. The AFT ages yield low denudation rates of 0. 020--0. 035 mm/a during the late Miocene, which correspond to a stable geomorphic and weak tectonic uplifting environment. The low denudation rates can be considered as the approximate tectonic uplifting rates. The AFT geochronology shows puroxysmully rapid cooling since the Pliocene and an apparent material unroofing of more than 3 km in the Xiaonanchuan area. This was not the result of simple denudation. The rapid cooling was coupled with the intensive orogeny since the Pliocene, which was driven by tectonic uplifting. The accelerated relief building was accompanied by a series of faulting, which caused the basin and the valley formation and sinking. The space pattern of the AFT ages also shows differential uplifting, which decreases northwardly. This trend is supported by the regional AFT data, which indicate that the exhumation decreases northwardly in eastern Kunlun. This trend also exists in cast-west orientation from the western Kunlun range to the eastern. The uplif- ting trend is also supported by gcomorphic characteristics including the elevation and the relief differences well as the distribution of the Late Cenozoic volcanism. 展开更多
关键词 eastern Kunlun Tibet Xiaonanchuan apatite fission track morphotectonic pliocene.
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Preliminary study on the spore-pollen assemblages found in the Cenozoic sedimentary rocks in Grove Mountains,east Antarctica and its climatic implications 被引量:1
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作者 方爱民 刘小汉 +3 位作者 王伟铭 李潇丽 俞良军 黄费新 《Chinese Journal of Polar Science》 2005年第1期23-32,共10页
Glaciogene sedimentary rocks have been found in modem tills of the Grove Mountains, east Antarctica during the 1998 - 1999 Chinese National Antarctic Research Expedition (CHNARE). Based on the lithilogic and sedimen... Glaciogene sedimentary rocks have been found in modem tills of the Grove Mountains, east Antarctica during the 1998 - 1999 Chinese National Antarctic Research Expedition (CHNARE). Based on the lithilogic and sedimentary features, these sedimentary rocks are correlated with Cenozoic sedimentary strata of the Pagodroma Group in the neighboring Prince Charles Mountains and the Sorsdal Formation in VestFold Hills. Sedimentary clasts contain sparsely Late Tertiary spores and pollens, including : Toroisporis ( Lygodiaceae), Osmunda, Granulatisporites ( Pteridaceae?) , Polypodiaceae, Podocarpus , Araucariaceae, Artemisia , Rhus , Nothofagidites , Proteacidites (Proteaceae) , Quercus , Fraxinoipollenites ( Oleaceae ) , Oleoidearumpollenites( Oleaceae ), Operculumpollis, and Tricolpopollenites. Most of the pollen and spores contained in these samples originate from local sources according to the conditions of their preservations as well as correlations with the microfossil assemblages found in the neighboring areas. The majority of the pollen assemblages, as represented by Podocarpus and Nothofagus, belong to the Weddellian biogeocenose, however some exotic components from the old sedimentary basement rocks may have been included during erosion of the proximal ice sheet. If the source areas of glaciogenic sedimentary rocks that bear the pollen and spores are assumed to be local, or in the up glacier areas, the pollen assemblages in these samples might represent an inland flora during a warmer period of the ice-sheet evolutionary history. The finding of the Artemisia and Chenopodiaceae in the pollen assemblages implies that they may belong to late Tertiary (most probably Pliocene). The absence of diatoms in the samples analyzed may indicate that there are no Cenozoic marine strata in the interior of the east Antarctica beyond the Grove Mountains. The significances of the finding of the Nothofagus in these pollen assemblages are discussed on the basis of current knowledge about the age, distribution and ecological conditions of this kind of fossils found in Sirius Group or other strata outcropped in Antarctica. As a preliminary conclusion, we think that the existence of the Cenozoic glaciogenenic rocks and their pollen assemblages present new evidence for a large scale glacial retreat history in Grove Mountains of east Antarctica, and thus support a dynamic East Antarctic Ice Sheet (EAIS). This is consistent with the interpretations of Webb et al. (1984). 展开更多
关键词 East Antarctica Grove Mountains Cenozoic sedimentary rocks sporepollen NOTHOFAGUS ARTEMISIA pliocene.
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Stress field modeling of northwestern South China Sea since 5.3 Ma and its tectonic significance 被引量:5
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作者 YANG Fengli ZHOU Zuyi +2 位作者 ZHANG Na LIU Ning NI Bin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2013年第12期31-39,共9页
Tectonically, the northwestern South China Sea (SCS) is located at the junction between three micro-plates, i.e., the Indochina, South China and Zhongsha-Xisha micro-plates, and involves three basins, i.e., the Ying... Tectonically, the northwestern South China Sea (SCS) is located at the junction between three micro-plates, i.e., the Indochina, South China and Zhongsha-Xisha micro-plates, and involves three basins, i.e., the Yinggehai Basin, the Qiongdongnan Basin and Xisha Trough in the east, and the Zhongjiannan Basin in the south. Since the Pliocene (5.3 Ma), the Yinggehai Basin has experienced repeated accelerating subsidence, high thermal fluid, and widely developing mud-rich overpressure chambers, abundant mud diapers and crust-mantle mixed CO2. While a large central canyon was developed in the Qiongdongnan Basin, new rift occurred in the Xisha ~rough. These characteristics demonstrate a single tectonic unit for the northwestern SCS, for which we have undertaken stress field modeling to understand its plate deformations and sedimen- tary responses. Our results demonstrate that an extension tectonic event occurred after 5.3 Ma in theYingge- hal-Qiongdongnan-Xisha trough area, which is characterized by thinner crust C〈16000 m), half-graben or graben structural style and thicker sedimentary sequences (〉3 500 m). A new rift system subsequently was developed in this area; this event was mainly driven by the combined effects of different movement veloc- ity and direction of the three micro-plates, and the far-field effect of the continental collision between the Indian Plate and the Tibetan Plateau, and subduction of the Pacific Plate underneath the Eurasian Plate. 展开更多
关键词 northwestern South China Sea pliocene stress field modeling rift system
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Deepwater Ventilation and Stratification in the Neogene South China Sea 被引量:3
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作者 李前裕 赵泉鸿 +5 位作者 钟广法 翦知湣 田军 成鑫荣 汪品先 陈木宏 《Journal of China University of Geosciences》 SCIE CAS CSCD 2007年第2期95-108,共14页
Combined data of physical property, benthic foraminifera, and stable isotopes from ODP Sites 1148, 1146, and 1143 are used to discuss deep water evolution in the South China Sea (SCS) since the Early Miocene. The re... Combined data of physical property, benthic foraminifera, and stable isotopes from ODP Sites 1148, 1146, and 1143 are used to discuss deep water evolution in the South China Sea (SCS) since the Early Miocene. The results indicate that 3 lithostratigraphic units, respectively corresponding to 21-17 Ma, 15-10 Ma, and 10-5 Ma with positive red parameter (a^*) marking the red brown sediment color represent 3 periods of deep water ventilation. The first 2 periods show a closer link to contemporary production of the Antarctic Bottom Water (AABW) and Northern Component Water(NCW), indicating a free connection of deep waters between the SCS and the open ocean before 10 Ma.After 10 Ma, red parameter dropped but stayed higher than the modern value (a^*=0), the CaCO3 percentage difference between Site 1148 from a lower deepwater setting and Site 1146 from an upper deepwater setting enlarged significantly, and benthic species which prefer oxygen-rich bottom conditions dramatically decreased. Coupled with a major negative excursion of benthic δ^13Cat ~10 Ma,these parameters may denote a weakening in the control of the SCS deep water by the open ocean.Probably they mark the birth of a local deep water due to shallow waterways or rise of sill depths during the course of sea basin closing from south to east by the west-moving Philippine Arc after the end of SCS seafloor spreading at 16-15 Ma. However, it took another 5 Ma before the dissolved oxygen approached close to the modern level. Although the oxygen level continued to stabilize, several Pacific Bottom Water (PBW) and Pacific Deep Water (PDW) marker species rapidly increased since ~6 Ma,followed by a dramatic escalation in planktonic fragmentation which indicates high dissolution especially after ~5 Ma. The period of 5-3 Ma saw the strongest stratified deepwater in the then SCS, as indicated by up to 40﹪ CaCO3 difference between Sites 1148 and 1146. Apart from a strengthening PDW as a result of global cooling and ice cap buildup on northern high latitudes, a deepening sea basin due to stronger subduction eastward may also have triggered the influx of more corrosive waters from the deep western Pacific. Since 3 Ma, the evolution of the SCS deep water entered a modern phase, as characterized by relative stable 10﹪ CaCO3 difference between the two sites and increase in infaunal benthic species which prefer a low oxygenated environment. The subsequent reduction of PBW and PDW marker species at about 1.2 Ma and 0.9 Ma and another significant negative excursion of benthic δ^13Cto a Neogene minimum at ~0.9 Ma together convey a clear message that the PBW largely disappeared and the PDW considerably weakened in the Mid-Pleistocene SCS. Therefore, the true modern mode SCS deep water started to form only during the "Mid-Pleistocene climatic transition" probably due to the rise of sill depths under the Bashi Strait. 展开更多
关键词 South China Sea MIOCENE pliocene PLEISTOCENE deep water evolution ventilation carbonate accumulation oxygen and carbon isotopes
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Upwelling Process of the Western Himalaya Mountains:Height and Velocity Estimation Evidenced by Formation and Evolution of the Zanda Basin,Tibet,China 被引量:3
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作者 ZHU Dagang MENG Xian' gang +5 位作者 SHAO Zhaogang YANG Chaobin HAN Jian'en YU Jia MENG Qingwei Lü Rongping 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2010年第2期280-295,共16页
Based on field geological survey, stratigraphic section measurement and indoor comprehensive investigation, the Zanda Basin's tectonic location in the Himalaya Plate was ascertained, and the formation and evolution o... Based on field geological survey, stratigraphic section measurement and indoor comprehensive investigation, the Zanda Basin's tectonic location in the Himalaya Plate was ascertained, and the formation and evolution of the Zanda Basin during the Pliocene to Early Pleistocene was classified as six stages: (a) primary rift-faulting stage, (b) quick rift-faulting Stage, (c) intensive rift-faulting stage, (d) stasis stage, (e) secondary rift-faulting stage, and (f) secondary quick rift-faulting stage. Based on this six-staged formation-evolution theory of the Zanda Basin, the upwelling process of the Western Himalaya Mountains from the Pliocene to Early Pleistocene was classified as the following five stages: (a) slow upwelling stage (5.4-4.4 Ma), (b) mid-velocity upwelling stage (4.4-3.5 Ma), (c) quick upwelling stage (3.5-3.2 Ma), (d) upwelling-ceasing stage (3.2-2.7 Ma), and (e) quick upwelling stage (2.7 Ma). Research has shown that in the duration from the Early Pliocene (4.7 Ma) to the End of Pliocene (2.67 Ma), which lasted 2.03 million years, the Himalaya Mountains had uplifted 1500 m at a velocity of 0.74 mm/a; this belongs to a mid-velocity upwening. During the 1.31 million years in the Early Stage of the Early Pleistocene, the Himalaya Mountains had risen up another 1500 m at a velocity of 1.15 mm/a; this is a rather quick upwelling. All of these data have shown that the upwelling of the Western Himalaya Mountains is along a complicated process with multi-stages, multi-velocities, and non-uniformitarian features. 展开更多
关键词 Zanda Basin pliocene to Early Pleistocene basin evolution mountain upwelling Western Himalaya Mountains.
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Taxonomy of the White-browed Shortwing(Brachypteryx montana)complex on mainland Asia and Taiwan:an integrative approach supports recognition of three instead of one species 被引量:1
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作者 Per Alstrom Pamela C.Rasmussen +12 位作者 Canwei Xia Magnus Gelang Yang Liu Guoling Chen Min Zhao Yan Hao Chao Zhao Jian Zhao Chengte Yao James A.Eaton Robert Hutchinson Fumin Lei Urban Olsson 《Avian Research》 CSCD 2018年第4期281-293,共13页
Background: The White-browed Shortwing(Brachypteryx montana) is widespread from the central Himalayas to the southeast Chinese mainland and the island of Taiwan, the Philippines and Indonesia. Multiple subspecies are ... Background: The White-browed Shortwing(Brachypteryx montana) is widespread from the central Himalayas to the southeast Chinese mainland and the island of Taiwan, the Philippines and Indonesia. Multiple subspecies are recognised, and several of these have recently been suggested to be treated as separate species based on differences in morphology and songs.Methods: We here analyse plumage, morphometrics, songs, two mitochondrial and two nuclear markers, and geographical distributions of the two mainland Asian taxa B. m. cruralis and B. m. sinensis and the Taiwan Residents B. m. goodfellowi.Results: We conclude that these differ congruently in morphology, songs and DNA. Male B. m. goodfellowi is the most divergent in plumage(sexually monomorphic, unlike the two others; male similar to female), and B. m. cruralis and B. m. sinensis differ in male plumage maturation. The song of B. m. cruralis is strongly divergent from the others, whereas the songs of B. m. sinensis and B. m. goodfellowi are more similar to each other. Brachypteryx m. sinensis and B. m. goodfellowi are sisters, with an estimated divergence time 4.1 million years ago(mya; 95% highest posterior distribution [HPD] 2.8–5.5 mya), and B. m. cruralis separated from these two 5.8 mya(95% HPD 4.1–7.5 mya). We also report notable range extensions of B. m. sinensis as well as sympatry between this taxon and B. m. cruralis in Sichuan Province, China. Brachypteryx m. montana from Java is found to be more closely related to Lesser Shortwing(B. leucophris) and Rusty-bellied Shortwing(B. hyperythra) than to the mainland Asian and Taiwan Residents taxa.Conclusion: Our data support a recent proposal to treat the three mainland Asian and Taiwan Residents taxa as three species, separate from B. montana sensu stricto: B. cruralis(central Himalayas to south central China and south Vietnam), B. sinensis(north central to southeastern part of China's Mainland) and B. goodfellowi(Taiwan Island). 展开更多
关键词 INTEGRATIVE TAXONOMY Morphology Song MIOCENE pliocene
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New fossil seeds of Eurya (Theaceae) from East Asia and their paleobiogeographic implications 被引量:2
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作者 Hai Zhu Yong-Jiang Huang +1 位作者 Tao Su Zhe-Kun Zhou 《Plant Diversity》 SCIE CAS CSCD 北大核心 2016年第3期125-132,共8页
Eurya has an excellent fossil record in Europe, but it has only a few fossil occurrences in East Asia though this vast area houses the highest modern diversity of the genus. In this study, three-dimensionally preserve... Eurya has an excellent fossil record in Europe, but it has only a few fossil occurrences in East Asia though this vast area houses the highest modern diversity of the genus. In this study, three-dimensionally preserved fossil seeds of Eurya stigrnosa (Ludwig) Mai from the late Pliocene of northwestern Yunnan, southwestern China are described. The seeds are compressed and flattened, slightly campylotropous, and nearly circular to slightly angular in shape. The surface of the seeds is sculptured by a distinctive foveolate pattern, consisting of funnel-shaped and finely pitted cells. Each seed valve contains a reniform or horseshoe-shaped embryo cavity, a characteristic condyle structure and an internal raphe. These fossil seeds represent one of the few fossil records of Eurya in East Asia. This new finding therefore largely extends the distributional ranges of Eurya during Neogene. Fossil records summarized here show that Eurya persisted in Europe until the early Pleistocene, but disappeared thereafter. The genus might have first appeared in East Asia no later than the late Oligocene, and dispersed widely in regions such as Japan, Nepal, and southwestern China. 展开更多
关键词 Seed fossil Eurya Late pliocene Nanbanbang Northwest Yunnan China
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