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Early Cretaceous Metasomatized Lithospheric Mantle beneath the Central Jiangnan Orogen in South China:Geochemical and Sr-Nd Isotope Evidence from the Tuanshanbei Dolerite
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作者 WANG Cheng WEI Hantao +1 位作者 LIU Qingquan YANG Zhao 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第3期602-616,共15页
It is well established that Cretaceous magmatism in the South China Block(SCB)is related to the Paleo-Pacific subduction.However,the starting time and the associated deep crust-mantle processes are still debatable.Maf... It is well established that Cretaceous magmatism in the South China Block(SCB)is related to the Paleo-Pacific subduction.However,the starting time and the associated deep crust-mantle processes are still debatable.Mafic dike swarms carry important information on the deep earth(including mantle)geodynamics and geochemical evolution.In the Jiangnan Orogen(South China).there is no information on whether the Mesozoic magmatic activities in this region are also directly related to the Pacific subduction or not.In this study,we present detailed zircon U-Pb geochronological,wholerock element and Sr-Nd isotope data for Early Cretaceous Tuanshanbei dolerite dikes,and provide new constraints on the condition of the lithospheric mantle and mantle dynamics of the SCB during that time.LA-ICP-MS zircon U-Pb dating suggests that this dolerite erupted in the Early Cretaceous(~145 Ma).All samples have alkaline geochemical affinities with K_(2)O+Na_(2)O=3.11-4.04 wt%,K_(2)O/Na_(2)O=0.50-0.72,and Mg^(#)=62.24-65.13.They are enriched in LILE but depleted in HFSE with higher initial^(87)Sr/^(86)Sr ratio(0.706896-0.714743)and lower ε_(Nd)(t)(-2.61 to-1.67).They have high Nb/U,Nb/La,La/Sm and Rb/Sr,and low La/Nb,La/Ta,Ce/Pb,Ba/Rb,Tb/Yb and Gd/Yb ratios.Such geochemical signatures suggest that the fractional crystallization is obvious but crustal contamination play a negligible role during magmatic evolution.Tuanshanbei dolerite were most likely derived from low-degree(2%-5%)partial melting of a phlogopite-bearing mantle material consisted of~85% spinel peridotite and~15% garnet peridotite previously metasomatized by asthenospherederived fluids/melts with minor subduction-derived fluids/melts.Slab-rollback generally lead to the upwelling of the hot asthenosphere.The upwelling of asthenosphere consuming the lithospheric mantle by thermo-mechanical-chemical erosion.The lithospheric mantle may have partially melted due to the heating by the upwelling asthenosphere and lithospheric extension.It is inferred that the Tuanshanbei dolerite might be associated with the initial slab rollback and corresponding lithospheric extension occurred potentially at ca.145 Ma. 展开更多
关键词 early cretaceous mafic dike metasomatized lithospheric mantle Tuanshanbei dolerite Jiangnan Orogen South China
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Arlenea delicata gen.et sp.nov.,a new ephedroid plant from the Early Cretaceous Crato Formation,Araripe Basin,Northeast Brazil
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作者 Alita Maria Neves Ribeiro Yong Yang +3 位作者 Antonio Alamo Feitosa Saraiva Renan Alfredo Machado Bantim Joao Tavares Calixto Junior Flaviana Jorge de Lima 《Plant Diversity》 SCIE CAS CSCD 2024年第3期362-371,共10页
Ephedroid macrofossils have been widely documented in Cretaceous deposits,including numerous from the Lower Cretaceous Yixian Formation of NE China.However,few ephedroid macrofossils have been reported from South Amer... Ephedroid macrofossils have been widely documented in Cretaceous deposits,including numerous from the Lower Cretaceous Yixian Formation of NE China.However,few ephedroid macrofossils have been reported from South America.Herein,we describe a new plant of the family Ephedraceae,Arlenea delicata gen.et sp.nov.,from the Lower Cretaceous Crato Formation of the Araripe Basin,Northeast Brazil,based on the vegetative and reproductive structures.It has the typical morphological characteristics of ephedroid plants,including fertile reproductive branches,opposite phyllotaxy,terminal female cones,a sympodial branching system,longitudinally striated internodes,and swollen nodes.Our new finding is unusual in having inner chlamydosperms subtended by two pairs of bracts,reproductive units connected to branches through swollen receptacles and a smooth seed surface.This new ephedroid taxon from the Crato Formation increases our understanding of plant diversity of this group during the Early Cretaceous.Furthermore,the general morphology(fleshy bracts and enlarged receptacles)of this new fossil discovery indicates that seeds of this plant may have been dispersed by animals such as pterosaurs(mainly the Tapejaridae)and birds(Enantiornithes and Ornituromorpha).If true,this would explain the cosmopolitan distribution of Ephedraceae in the Lower Cretaceous. 展开更多
关键词 early cretaceous Gnetophytes Arlenea delicata Ephedrales Crato Formation
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Investigation of the Petrological and Geochemical Characteristics of Siderite in the Early Cretaceous Sandstone of Lacustrine Sedimentary Sequence in the Erlian Basin from Northeastern China
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作者 Yunlong Zhang Mingming Tian +3 位作者 Huili Xie Xide Li Wusheng Liu Shiqi Ni 《Journal of Geoscience and Environment Protection》 2024年第6期305-321,共17页
Siderite is a prevalent authigenic mineral in siliciclastic rocks, which usually occurred in eodiagensis period and could be used as an indicator of sedimentary environment. Some siderite precipitated in burial depth ... Siderite is a prevalent authigenic mineral in siliciclastic rocks, which usually occurred in eodiagensis period and could be used as an indicator of sedimentary environment. Some siderite precipitated in burial depth with geochemical information of basin fluid evolution. The crystal morphology, geochemical composition, and isotope values are influenced by physical and geochemical environment of precipitation. In this study, samples from the Early Cretaceous of Erlian basin in the northwestern China were collected, and mineralogy, bulk and in-situ geochemistry, C and O isotopes were analyzed to comprehensively investigate the sedimentary and diagenetic environment that the sediments experienced. Six lithofaices with three types of crystal habits were recognized in the siderite-rich sandstone, bundle crystal in spherical forms, blocky rhombs in intergranular pore and cleavage of muscovite, and micro bundle and mosaic crystals aggregates in nodular. The siderite growth proceeds through micro bundle and mosaic crystals to bundle siderite aggregates and then into blocky rhombs. The crystal evolution is also reflected by geochemical composition. The micro bundle and mosaic crystals are Casiderite. The spheritic shaped bundle aggregates are Ca-Mn-siderite. The blocky rhomb siderite shows gray part and bight part with Ca, Mg and Mn varies. Increase of Ca in block rhomb siderite suggests burial and mesodiagenesis, the high content of Mn may have linkage with eogenetic effects. The relatively positive and slightly negative δ13C value indicates meteoric water domination and influence of organic matter evolution in shallow buried time. The narrow ranges negative δ18O value suggest a small span of temperature of siderite formation. 展开更多
关键词 SIDERITE Sedimentary Environment Lacustrine Deposition early cretaceous Erlian Basin
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Early Cretaceous Thrust and Nappe Tectonics in North Qilian Shan,Northern Tibetan Plateau:Evidence from Field Mapping,Geochronology,and Deep Structural Analysis 被引量:1
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作者 HAN Lele DING Weicui +9 位作者 CHEN Xuanhua SHAO Zhaogang ZHANG Da XIAO Yongjun HE Chengguang WANG Zengzhen LI Bing ZHANG Yiping XU Shenglin WANG Ye 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2023年第4期1058-1077,共20页
The North Qilian Shan fold and thrust belt,located at the northern Tibetan Plateau and southern margin of the Hexi Corridor,is a key tectonic unit to decode the formation and expansion of the plateau.Previous studies ... The North Qilian Shan fold and thrust belt,located at the northern Tibetan Plateau and southern margin of the Hexi Corridor,is a key tectonic unit to decode the formation and expansion of the plateau.Previous studies emphasize the Cenozoic deformation due to the far-field response to the Indo-Asian collision,but the Mesozoic deformations are poorly constrained in this area.We conducted detailed field mapping,structural analysis,geochronology,and structural interpretation of deep seismic reflectional profiling and magnetotelluric(MT)sounding,to address the superposed results of the Mesozoic and Cenozoic deformation.The results recognized the North Qilian thrust and nappe system(NQTS),the root and the frontal belt are the North Qilian thrust(NQT),and the Yumu Shan klippe(YK),respectively.The middle belt is located between the NQT and the YK.Monzonitic granite zircon U-Pb dating from the middle belt yields an age of ca.415 Ma,which is similar to south NQT.The thrusting displacement is estimated at ca.48 km by structural interpretation of deep profiles.The timing is constrained in the early stage of the Early Cretaceous by the formation of simultaneous growth strata.We suggest that the NQTS has resulted from the far-field effect of the Lhasa-Qiangtang collision,and the Yumu Shan is uplifted by the superposed Cenozoic deformation. 展开更多
关键词 GEOCHRONOLOGY structural analysis seismic reflectional and MT profiling early cretaceous North Qilian thrust and nappe system Tibetan Plateau
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Geochronology and Geochemistry of Early Cretaceous A-type Granites in Central-Eastern Inner Mongolia,China:Implications for Late Mesozoic Tectonic Evolution of the Southern Great Xing'an Range
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作者 ZHANG Yanwen ZHANG Xiaofei +6 位作者 CHEN Lixin PANG Zhenshan CHEN Hui XUE Jianling ZHOU Yi TENG Chao CHEN Guochao 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2023年第4期1094-1111,共18页
The southern Great Xing'an Range is the most critical Sn-polymetallic metallogenic belt in northeast China.However,the tectonic setting of the Early Cretaceous magmatic-metallogenic”flare-up“event remains uncert... The southern Great Xing'an Range is the most critical Sn-polymetallic metallogenic belt in northeast China.However,the tectonic setting of the Early Cretaceous magmatic-metallogenic”flare-up“event remains uncertain.This paper presents an integrated study on the occurrence,petrology,zircon U-Pb ages,whole-rock geochemistry,and in situ zircon Hf isotopes for Wenduerchagan granites of Xi Ujimqin Banner,central-eastern Inner Mongolia.These granites consist primarily of granite porphyry(with ages of 137±1 Ma and 138±1 Ma)and(porphyritic)alkali feldspar granite(with an age of 141±2 Ma),corresponding to the early Early Cretaceous.They are A-type granites characterized by high silicon,alkali,and TFeO/MgO contents while being depleted of Ba,Nb,Ta,Sr,P,and Ti.They show right-dipping trend rare-earth element distribution characteristics with negative Eu anomalies(Eu/Eu^(*)=0.01-0.20)and weak heavy rare-earth element fractionation((Gd/Yb)_(N)=0.77-2.30).They demonstrate homogeneous zircon Hf isotopic compositions(positiveε_(Hf)(t)values from+5.3 to+7.1 and young two-stage Hf model ages of 851-742 Ma)and high zircon saturation temperatures(av.810℃).These geochemical characteristics indicate that Wenduerchagan granites originated from the partial melting of juvenile crust under high-temperature and low-pressure conditions.Wenduerchagan granites most likely formed in a post-collisional compression-extension transition regime caused by the closure of the Mongol-Okhotsk Ocean,when combined with regional geology.Such a transition regime can probably be attributed to the upwelling of the asthenospheric mantle caused by the break-off of a subducted Mongol-Okhotsk oceanic slab.Upwelling asthenospheric mantle provided sufficient energy and favorable tectonic conditions for magmatism and mineralization of the Early Cretaceous. 展开更多
关键词 magmatism and mineralization A-type granite post-collisional environment early cretaceous southern Great Xing'an Range Mongol-Okhotsk Ocean
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A New Basal Titanosaur (Dinosauria: Sauropoda) from the Early Cretaceous of China 被引量:17
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作者 YOUHailu TANGFeng LUOZhexi 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2003年第4期424-429,共6页
A new dinosaur of Early Cretaceous age was recently discovered from the Mazongshan area of northwestern Gansu Province, China. The new dinosaur represents a new genus and species of Sauropoda, and is among the most ba... A new dinosaur of Early Cretaceous age was recently discovered from the Mazongshan area of northwestern Gansu Province, China. The new dinosaur represents a new genus and species of Sauropoda, and is among the most basal members of Titanosauria. Its finding also suggests that titanosaurs might have originated in Asia no later than the Early Cretaceous. 展开更多
关键词 DINOSAURIA TITANOSAURIFORMES TITANOSAURIA gen. et sp. nov. early cretaceous Mazongshan Gansu Province China
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On a New Genus of Basal Neoceratopsian Dinosaur from the Early Cretaceous of Gansu Province, China 被引量:13
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作者 YOU Hailu LI Daqing +2 位作者 JI Qiang Matthew C. LAMANNA Peter DODSON 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2005年第5期593-597,共5页
A new genus and species of basal neoceratopsian dinosaur, Auroraceratops rugosus, is reported based on material from the Early Cretaceous Xinminpu Group in the Gongpoquan Basin of Gansu Province, China. Auroraceratops... A new genus and species of basal neoceratopsian dinosaur, Auroraceratops rugosus, is reported based on material from the Early Cretaceous Xinminpu Group in the Gongpoquan Basin of Gansu Province, China. Auroraceratops is represented by a nearly complete skull and low jaws, and different greatly from all other neoceratopsians by its considerable breadth of the nasals, fungi form expansion of the dorsal end of the lacrimal, highly developed rugosity of the jugal, dentary and surangular, and inflated, striated premaxillary teeth. The finding of Auroraceratops adds diversity and helps elucidate the evolution of basal neoceratopsian dinosaurs. 展开更多
关键词 DINOSAURIA Neoceratopsia early cretaceous Xinminpu Group Gongpoquan Basin Gansu Province
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A New Enantiornitine Bird with Four Long Rectrices from the Early Cretaceous of Northern Hebei,China 被引量:12
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作者 ZHENG Xiaoting ZHANG Zihui HOU Lianhai 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2007年第5期703-708,共6页
Paraprotopteryx gracilis, a new enantiornithine bird from the Early Cretaceous Yixian Formation in Fengning, northern Hebei Province is erected, based on the following characters: Yshaped furcula with a long hypoclei... Paraprotopteryx gracilis, a new enantiornithine bird from the Early Cretaceous Yixian Formation in Fengning, northern Hebei Province is erected, based on the following characters: Yshaped furcula with a long hypocleidum and a much narrow interclavicular angle, and the morphology of the sternum are different from other enantiornithines. Additionally, alular digit bearing the biggest manual claw extends distally to the distal end of the major metacarpal; the minor metacarpal is slender than the major metacarpal. Carpometacarpus only fused proximally; astragalus and calcaneum partially fused to one another but unfused to the tibia. This is the first record of Mesozoic birds in having four long rectrices, which may represent morphologically a secondary sexual character, an intermediate stage from elongated scale to branched feather, and possess functional advantage in supplementing the lifting surface to compensate the unskilled flight. 展开更多
关键词 early cretaceous Paraprotopteryx gracilis enantiornithine rectrices Fengning Hebei Province
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A Basal Titanosauriform from the Early Cretaceous of Guangxi, China 被引量:10
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作者 MO Jinyou WANG Wei +2 位作者 HUANG Zhitao HUANG Xin XU Xing 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2006年第4期486-489,共4页
Based on a partial postcranial skeleton collected from the Lower Cretaceous Napai Formation of Guangxi, China, we erect a new sauropod taxon, Fusuisaurus zhaoi gen. et sp. nov. The holotype specimen consists of the le... Based on a partial postcranial skeleton collected from the Lower Cretaceous Napai Formation of Guangxi, China, we erect a new sauropod taxon, Fusuisaurus zhaoi gen. et sp. nov. The holotype specimen consists of the left ilium, left pubis, anterior caudals, most of the dorsal ribs and distal end of the left femur. Fusuisaurus zhaoi is diagnosed by a unique combination of character states among the known sauropods. It displays several synapomorphies of Titanosauriformes but lacks many derived features seen in other titanosauriforms, suggesting that the new taxon represents the basalmost known titanosauriform and providing new evidence that Titanosauriformes originated from Asia. A size comparison suggests that Fusuisaurus zhaoi is among the largest Early Cretaceous sauropods, providing an important addition to the Early Cretaceous Chinese sauropod diversity. 展开更多
关键词 TITANOSAURIFORMES early cretaceous Fusui County GUANGXI China
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A New Ctenochasmatid Pterosaur from the Early Cretaceous of Liaoning Province 被引量:10
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作者 DONGZhiming LUEJunchang 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2005年第2期164-167,共4页
Based on a nearly complete lower jaw from the Early Cretaceous of Liaoning Province, a new ctenochasmatid pterosaur: Liaoxipterus brachyognathus gen. et sp. nov. is erected. Liaoxipterus brachyognathus is different fr... Based on a nearly complete lower jaw from the Early Cretaceous of Liaoning Province, a new ctenochasmatid pterosaur: Liaoxipterus brachyognathus gen. et sp. nov. is erected. Liaoxipterus brachyognathus is different from any known pterosaurs with skulls preserved from western Liaoning Province and its peripheral areas in that the anterior part of the mandibular symphysis is expanded, being widest between the fourth alveolus of each side. Liaoxipterus brachyognathus is assigned to Ctenochasmatidae based on the following characters: the rounded anterior end of the lower jaw is spatulated and dorsoventrally flattened and marked heterodonty in the dentition is absent. It differs from other ctenochasmatid pterosaurs in having relatively small number of teeth. Liaoxipterus is distinguished from some ornithocheirids, which have expanded anterior parts of the mandibular symphyses, such as Anhanguera piscator, Coloborhynchus robustus in which the teeth of the new pterosaur are not as variable. 展开更多
关键词 Liaoxipterus Ctenochasmatidae Jiufotang Formation early cretaceous Liaoning Province
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A New Hadrosauriform Dinosaur from the Early Cretaceous of Gansu Province,China 被引量:8
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作者 YOU Hailu LI Daqing LIU Weichang 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2011年第1期51-57,共7页
A new basal hadrosauriform dinosaur, Xuwulongyueluni gen. et sp. nov., is reported based on an articulated specimen including a complete cranium, almost complete axial skeleton, and complete left pelvic girdle. The sp... A new basal hadrosauriform dinosaur, Xuwulongyueluni gen. et sp. nov., is reported based on an articulated specimen including a complete cranium, almost complete axial skeleton, and complete left pelvic girdle. The specimen is recovered from the Early Cretaceous Yujingzi Basin in the Jiuquan area, Gansu Province of northwestern China. Xuwulong is among the most basal members of hadrosauriform dinosaurs, and distinguished by its unique lower jaw in having a V-shaped rostral end of the dentary in lateral view and a mandibular articular surface which levels with mid-height of the dentary ramus, as well as an enlarged and downturned prepubic process. Including Xuwulong, three basal hadrosauriforms have been discovered from the Early Cretaceous Xinminpu Group in the Mazongshan area, making it an important area to study the origin and early evolution of duck-billed dinosaurs. 展开更多
关键词 DINOSAUR hadrosauriform gen. et sp. nov. early cretaceous Xinminpu Group GANSU
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An Early Cretaceous Avialian Bird, Shenzhouraptor sinensis from Western Liaoning, China 被引量:8
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作者 Ji Qiang, Ji Shu’an, You Hailu, Zhang Jianping,Zhang Hongbin, Zhang Nanjun, Yuan Chongxi and Ji XinxinDepartment of Earth Sciences, Nanjing University, Nanjing, Jiangsu 100093Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037 School of Earth and Space Sciences, Peking University, Beijing 100871China University of Geosciences, Beijing 100083 China Dinosaur Park of Changzhou, Changzhou, Jiangsu 213002 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2003年第1期21-27,共7页
This paper describes an avialian bird from the Early Cretaceous JiufotangFormation in Yixian county, western Liaoning China, which is named as Shenzhouraptor sinensis by Jiet al. on July 15, 2002. Shenzhouraptor sinen... This paper describes an avialian bird from the Early Cretaceous JiufotangFormation in Yixian county, western Liaoning China, which is named as Shenzhouraptor sinensis by Jiet al. on July 15, 2002. Shenzhouraptor sinensis is characterized by no teeth in its mouth, theforelimbs longer than the hindlimbs, a long tail with more than 23 caudal vertebrae, U-shapedwishbone, and remiges longer than the total length of ulna and manus. It is certain that the newavialian bird is really capable of powerful flight, representing a missing link between theropoddinosaurs and birds. 展开更多
关键词 Avialian birds early cretaceous Jiufotang Formation western Liaoning China
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New Azhdarchid Pterosaur from the Early Cretaceous of Western Liaoning 被引量:8
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作者 LUEJunchang JIQiang 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2005年第3期301-307,共7页
A nearly complete skeleton with a lower jaw of pterosaur from the Early Cretaceous of western Liaoning is described and assigned to a new genus, Eoazhdarcho gen. nov.. The new genus is characterized by a relatively sm... A nearly complete skeleton with a lower jaw of pterosaur from the Early Cretaceous of western Liaoning is described and assigned to a new genus, Eoazhdarcho gen. nov.. The new genus is characterized by a relatively small size, the ratio of the length to width of the middle series cervical vertebrae approximately 3.5 and the ratio of humeral length to femoral length approximately 0.96. The humerus of Eoazhdarcho shows great resemblances to that of previously described Azhdarchidae, so it is assigned to the family Azhdarchidae. 展开更多
关键词 Eoazhdarcho Azhdarchidae early cretaceous Liaoning Province
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Enantiornithine Bird with Diapsidian Skull and Its Dental Development in the Early Cretaceous in Liaoning, China 被引量:8
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作者 GONGEnpu HOULianhai WANGLixia 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2004年第1期1-7,共7页
A Iarge number of enantiornithine birds are discovered from the Early Cretaceous Jiufutang Formation in western Liaoning, China. They are all small-sized birds with a few small teeth. The enantiornithine bird from the... A Iarge number of enantiornithine birds are discovered from the Early Cretaceous Jiufutang Formation in western Liaoning, China. They are all small-sized birds with a few small teeth. The enantiornithine bird from the Jiufutang Formation in the Shangheshou area, Chaoyang, Liaoning Province reported in this paper is the largest individual known in all enantiornithine birds of the Early Cretaceous. However, its teeth possess a feature of pseudoheterodont. Some different development stages of the new teeth substitute the earlier stages and the stages of development are preserved in this specimen. This development pattern is similar to that of Archaeopteryx and alligator but not dinosaur. A well-developed postorbital was also preserved in the skull, which was a diapsidian skull like that of Confuciusornis. Additionally, the distinctive preservation of its prefrontal distinguishes it from other enantiornithine birds of the Early Cretaceous. 展开更多
关键词 early cretaceous enantiornithine dental development Aberratiodontus wui
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New Eoenantiornithid Bird from the Early Cretaceous Jiufotang Formation of Western Liaoning, China 被引量:8
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作者 LI Li DUAN Ye +3 位作者 HU Dongyu WANG Li CHENG Shaoli HOU Lianhai 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2006年第1期38-41,共4页
Enantionithine birds are the most blooming branch of early birds and have distinct diversities. A large number of enantionithine birds have been reported from the Early Cretaceous Jiufotang Formation in western Liaoni... Enantionithine birds are the most blooming branch of early birds and have distinct diversities. A large number of enantionithine birds have been reported from the Early Cretaceous Jiufotang Formation in western Liaoning, China. Recently, we discovered a new eoenantiornithid bird from the Jiufotang Formation in Dapingfang Town, western Liaoning. A new eoenantiornithid bird, Dapingfangornis sentisorhinus gen. et sp. nov., is erected based on this complete skeleton with a skull. The new bird is distinguished from other known Mesozoic birds in a medium to small size, a distinct thorn-like process on the nasals, a sternum with a long and a short lateral processes. The thorn-like process on the nasal has not been discovered among known fossil birds, thus the discovery also provides new materials on the diversities of early birds. 展开更多
关键词 Eoenantiornithid Dapingfangornis sentisorhinus Jiufotang Formation early cretaceous western Liaoning
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Early Cretaceous Tectonics and Evolution of the Tibetan Plateau 被引量:7
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作者 WU Zhenhan ZHAO Zhen +1 位作者 Patrick J. BAROSH YE Peisheng 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2016年第3期847-857,共11页
Selected geological data on Early Cretaceous strata, structures, magmatic plutons and volcanic rocks from the Kunlun to Himalaya Mountains reveal a new view of the Early Cretaceous paleo-tectonics and the related geod... Selected geological data on Early Cretaceous strata, structures, magmatic plutons and volcanic rocks from the Kunlun to Himalaya Mountains reveal a new view of the Early Cretaceous paleo-tectonics and the related geodynamic movement of the Tibetan Plateau. Two major paleo- oceans, the Mid-Tethys Ocean between the Qiangtang and Lhasa blocks, and the Neo-Tethys Ocean between the Lhasa and Himalayan blocks, existed in the Tibetan region in the Early Cretaceous. The Himalayan Marginal and South Lhasa Seas formed in the southern and northern margins of the Neo- Tethys Ocean, the Central Tibet Sea and the Qiangtang Marginal Sea formed in the southern and northern margins of the Mid-Tethys Ocean, respectively. An arm of the sea extended into the southwestern Tarim basin in the Early Cretaceous. Early Cretaceous intensive thrusting, magmatic emplacement and volcanic eruptions occurred in the central and northern Lhasa Block, while strike- slip formed along the Hoh-Xil and South Kunlun Faults in the northern Tibetan region. Early Cretaceous tectonics together with magmatic K20 geochemistry indicate an Early Cretaceous southward subduction of the Mid-Tethys Oceanic Plate along the Bangoin-Nujiang Suture which was thrust ~87 km southward during the Late Cretaceous-Early Cenozoic. No intensive thrust and magmatic emplacement occurred in the Early Cretaceous in the Himalayan and southern Lhasa Blocks, indicating that the spreading Neo-Tethys Oceanic Plate had not been subducted in the Early Cretaceous. To the north, terrestrial basins of red-beds formed in the Hoh-Xil, Kunlun, Qilian and the northeastern Tarim blocks in Early Cretaceous, and the Qiangtang Marginal Sea disappeared after the Qiangtang Block uplifted in the late Early Cretaceous. 展开更多
关键词 early cretaceous paleo-tectonics subduction of the oceanic plate K20 geochemistry of granites Bangoin-Nujiang Suture the Tibetan Plateau
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A Large Therizinosauroid(Dinosauria:Theropoda) from the Early Cretaceous of Northwestern China 被引量:5
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作者 LI Daqing PENG Cuo +4 位作者 YOU Hailu Matthew C. LAMANNA Jerald D. HARRIS Kenneth J. LACOVARA ZHANG Jianping 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2007年第4期539-549,共11页
We herein describe an associated partial postcranial skeleton of a theropod dinosaur discovered in the Lower Cretaceous Xinminpu Group of the Yujingzi Basin, in the Jiuquan area of Gausu Province, northwestern China. ... We herein describe an associated partial postcranial skeleton of a theropod dinosaur discovered in the Lower Cretaceous Xinminpu Group of the Yujingzi Basin, in the Jiuquan area of Gausu Province, northwestern China. Features of its humerus, such as strongly expanded proximal and distal ends, a well developed medial tuberosity, distal condyles expressed on the humeral cranial surface, and a hypertrophied entepicondyle, definitively establish the therizinosauroid affinities of the specimen. It differs from other therizinosauroids in having a shallow, poorly demarcated glenoid fossa with a prominent rounded and striated tumescence on the dorsomedial surface of its scapular portion, and a pubis with a strongly concave cranial margin. It represents a new taxon, Suzhousaurus megatherioides gen. et sp. nov. Cladistic analysis recovers Suzhousaurus as the sister taxon of Nothronychus mckinleyi from the mid-Cretaceous of western North America; together, they are basal members of the Therizinosauroidea, more derived than the Early Cretaceous Falcarius and Beipiaosaurus but less derived than Alxasaurus and the Therizinosauridae. Along with "Nanshiungosaurus" bohlini from possibly coeval beds in the Mazongshan area of northern-most Gansu, Suzhousaurus represents one of the largest-known Early Cretaceous therizinosauroids, demonstrating that this clade attained considerable body size early in its evolutionary history. 展开更多
关键词 DINOSAURIA THEROPODA Therizinosauroidea Yujingzi Basin early cretaceous Jiuquan area Gansu Province China
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New Schizolepis Fossils from the Early Cretaceous in Inner Mongolia, China and its Phylogenetic Position 被引量:5
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作者 XU Xiaohui LI Ruiyun +3 位作者 DONG Chong WANG Qiujun JIN Peihong SUN Bainian 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2013年第5期1250-1263,共14页
Three Schizolepis species collected from the Lower Cretaceous layer of the Huolinhe Basin, Inner Mongolia, China are described. These fossils are Schizolepis longipetiolus Xu XH et Sun BN sp. nov., which is a new spec... Three Schizolepis species collected from the Lower Cretaceous layer of the Huolinhe Basin, Inner Mongolia, China are described. These fossils are Schizolepis longipetiolus Xu XH et Sun BN sp. nov., which is a new species, Schizolepis cf. heilongjiangensis Zheng et Zhang, and Schizolepis neimengensis Deng. The new species is a well-preserved female cone, slender and cylindrical in shape. The seed-scale complexes have long petioles and are arranged on the cone axis loosely and helically. The seed scales are divided into two lobes from the base. Each lobe is semicircular or elongate ligulate in shape, widest at the middle or the lower middle part, with an obtuse or bluntly pointed apex. The inner margin is almost straight and the outer margin is strongly arched. On the surface of the lobe, there are longitudinal and somewhat radial striations from the base to the margin. The seed is borne on the adaxial surface at the base or middle of each lobe. Schizolepis was estabfished in 1847, and, although more than twenty species have been discovered and reported, its phylogenetic position is controversial because of the imperfection of fossils. Most authors have considered there to be a close evolutionary relationship between Schizolepis and extant Pinaceae. Here, we analyze characteristics and compare Schizolepis with Picea crassifolia Kom, which is morphologically most similar to Schizolepis. The results indicate that the genus probably has a distant evolutionary relationship with extant Pinaceae. A detailed statistical analysis of the global paleogeographic distribution of Schizolepis showed that all the fossils of this genus appeared in strata ranging from the Upper Triassic to the Lower Cretaceous in the North Hemisphere, being rare in the Upper Triassic and Lower Jurassic, but being very common from the Middle Jurassic to the Lower Cretaceous, and particularly abundant in the Lower Cretaceous. According to the statistical results, we speculate that the genus originated in Europe in the Late Triassic then spread from Europe to Asia between the Late Triassic and the Late Jurassic. In the Early Cretaceous most species existed in China's three northeastern Provinces and the Inner Mongolia Autonomous Region and adjacent areas. Combining the paleogeographic distribution of the genus with ancient climatic factors, we deduced that Schizolepis began to decline and became extinct in the Early Cretaceous, and the reason for its extinction is closely related to the icehouse climate during the Early Cretaceous. 展开更多
关键词 Schizolepis systematic evolution paleogeographic distribution early cretaceous cause of extinction Inner Mongolia
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High-precision geochronology of the Early Cretaceous Yingcheng Formation and its stratigraphic implications for Songliao Basin,China 被引量:6
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作者 Tiantian Wang Chengshan Wang +5 位作者 Jahandar Ramezani Xiaoqiao Wan Zhiqiang Yu Youfeng Gao Huaiyu He Huaichun Wu 《Geoscience Frontiers》 SCIE CAS CSCD 2022年第4期89-97,共9页
The Songliao Basin in Northeast Asia is the largest and longest-lived rift basin and preserves a nearcontinuous continental succession of the most of the Cretaceous period,providing great material to investigate the a... The Songliao Basin in Northeast Asia is the largest and longest-lived rift basin and preserves a nearcontinuous continental succession of the most of the Cretaceous period,providing great material to investigate the adaption of the terrestrial systems to the Cretaceous greenhouse climate and tectonic events.However,the paucity of precise and accurate radioisotopic ages from the Early Cretaceous strata of the Songliao Basin has greatly held back the temporal and causal correlation of the continental records to the global Early Cretaceous records.Three tuff layers intercalated in the Yingcheng Formation have been intercepted by the SK-2 borehole,which offer excellent materials for radioisotopic dating and calibration of the chronostratigraphy of the Lower Cretaceous sequence of Songliao Basin.Moreover,the Yingcheng Formation recorded the largest and the last of the two major volcanic events in Songliao Basin,which also represents a turning point in the basin evolution history of Songliao from syn-rift stage to post-rift stage.Here we report high-precision U–Pb zircon geochronology by the CA-ID-TIMS technique on three tuff samples from the Yingcheng Formation of the SK-2 borehole in the Songliao Basin to construct a greatly improved,absolute age framework for the Yingcheng Formation and provide crucial age constraints for the Songliao Lower Cretaceous Strata.The new CA-ID-TIMS geochronology constrained the Yingcheng Formation at 102.571+0.320/-2.346 Ma to ca.113 Ma,correlating to the Albian Stage.Combined with the previous published Songliao geochronology,the Quantou Formation is constrained to between 96.442+0.475/-0.086 Ma and 91.923+0.475/-0.086 Ma;the Denglouku Formation is constrained to between 102.571+0.320/-2.346 Ma and 96.442+0.475/-0.086 Ma;the age of the Shahezi Formation is estimated at ca.113 Ma to ca.118 Ma,which could extend to ca.125 Ma in some locations in Songliao Basin.The major unconformity between the Yingcheng Formation and the Denglouku Formation,which represents the transition of the basin from syn-rift to post-rift is thus confined to between 102.571+0.320/-2.346 Ma and 96.442+0.475/-0.086 Ma.This is roughly contemporaneous with the change in the direction of the paleo-Pacific plate motion from west-southwest to north or northwest in mid-Cretaceous,suggesting their possible connections. 展开更多
关键词 U–Pb geochronology Songliao Basin early cretaceous Yingcheng Formation China
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Male spike strobiles with Gnetum affinity from the Early Cretaceous in western Liaoning,Northeast China 被引量:5
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作者 Shuang-Xing GUO jin-Geng SHA +1 位作者 Li-Zeng BIAN Yin-Long QIU 《Journal of Systematics and Evolution》 SCIE CSCD 北大核心 2009年第2期93-102,共10页
A fossil with Gnetum affinity was found in the Jianshangou Member (Barremian Age) of the Yixian Formation (Lower Cretaceous Epoch) of the Jehol Group in western Liaoning, northeastern China. The single fossil spec... A fossil with Gnetum affinity was found in the Jianshangou Member (Barremian Age) of the Yixian Formation (Lower Cretaceous Epoch) of the Jehol Group in western Liaoning, northeastern China. The single fossil specimen is represented by both elongate-cylindrical male spike strobiles which borne within a nodal bract of cauliflorous branch. The spike strobiles have apparent nodes, invisible internodes, and numerous verticillate involucral collars. The microsporangiate units within involucral collars are not seen. The male spike strobiles with verticillate involucral collars occur exclusively in Gnetum; hence, the fossil strobiles are attributed to a new taxon, Khitania columnispicata gen. & sp. nov., being closely related to Gnetum. The general isotopic dating suggests an age of Barremian, ca. 125-122 million years (Myr) ago for the Jianshangou Member. The palaeoecological and palaeoclimatic inference based on the compositions of flora and fauna, and lithological characters of the fossil locality suggests that the fossil plants grew in a subtropical mesophytic forest and under a warmer climate. The remains of male spike strobiles are the first record of gnetalean macrofossil. It documents the evolution of the distinct gnetoid morphology and indicates a wider range of distribution of Gnetaceae in the Early Cretaceous than present day. 展开更多
关键词 BIOGEOGRAPHY early cretaceous Gnetum affinity male spike strobiles northeastern China.
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