A skull and a series of associated cervical vertebrae （ZLJ0112） discovered from the Lower Lufeng Formation （Lower Jurassic） are determined as a juvenile specimen of Lufengosaurus huenei Young 1941 based on amended...A skull and a series of associated cervical vertebrae （ZLJ0112） discovered from the Lower Lufeng Formation （Lower Jurassic） are determined as a juvenile specimen of Lufengosaurus huenei Young 1941 based on amended autapomorphies. Differences between ZLJ0112 and the holotype （subadult specimen） are considered as ontogenetic characteristic changes of L. huenei. Since some of these differences are present in other prosauropod dinosaurs （i.e., forms of the maxillary vascular foramen are irregular; the frontal contribution to the dorsal margin of the orbit is substantial; the frontal contribution to the supratemporal fossa is absent; the supratemporal fenestra is visible in lateral view; the supraoccipital inclined at 75 degrees; the parasphenoid rostrum lies level with the occipital condyle; the retroarticular process is short; the axial postzygapophysis project caudally beyond the end of the centrum） they may be common ontogenetic changes in prosauropod dinosaurs.展开更多
This paper is concerned with the geochemical features of major elements, transitionmetal elements, large ion lithophile elements, rare-earth elements and Sr isotopes in alkaline-ul-trabasic rocks in the Jijie complex ...This paper is concerned with the geochemical features of major elements, transitionmetal elements, large ion lithophile elements, rare-earth elements and Sr isotopes in alkaline-ul-trabasic rocks in the Jijie complex of Lufeng, Yunnan Province, which is located in southernSichuan-Yunnan rift zone, one of Luoci alkaline-ultrabasic complexes in central Ynnnan.Moreover, its origin pertaining primary magma, magma soure region, fractional crystallization,etc. are also discussed in the present paper.展开更多
A new theropod dinosaur, Shidaisaurusjinae gen. et sp. nov., has been described on the basis of an incomplete skeleton. The specimen was found near the base of the Upper Lufeng Formation （early Middle Jurassic） in Y...A new theropod dinosaur, Shidaisaurusjinae gen. et sp. nov., has been described on the basis of an incomplete skeleton. The specimen was found near the base of the Upper Lufeng Formation （early Middle Jurassic） in Yunnan, China. It is the first theropod dinosaur from the Middle Jurassic of Yunnan. Shidaisaurus jinae is distinguishable from other Jurassic theropods by certain features from the braincase, axis, and pelvic girdle. The absence of any pleurocoels in the axis or in any anterior dorsal vertebrae suggests that the new Lufeng theropod is relatively primitive and more plesiomorphic than most of the Middle to Late Jurassic theropods from China. Most Chinese taxa of Jurassic theropod dinosaurs have not been well described; a further detailed study will be necessary for us to determine their phylogenetic relationships with Shidaisaurusjinae.展开更多
The Miocene epoch marks the most crucial period during the Cenozoic cooling trend, characterized by the Middle Miocene Climatic Optimum(MMCO) and a series of short–lived cooling events(Miocene isotope events).To unde...The Miocene epoch marks the most crucial period during the Cenozoic cooling trend, characterized by the Middle Miocene Climatic Optimum(MMCO) and a series of short–lived cooling events(Miocene isotope events).To understand the paleoenvironmental evolution along the shallow water shelf in the South China Sea during the Miocene, the benthic foraminiferal assemblage and total organic carbon content(TOC) were analyzed at Hole LF14 located in the Lufeng Sag, northern South China Sea. Three benthic foraminiferal assemblages(e.g., the Uvigerina spp. assemblage, the Cibicides spp. assemblage, and the Cibicidoides spp. assemblage), corresponding to different watermass conditions, were recognized based on Q–mode factor analysis. Early studies suggested that Hole LF14 was deposited under semienclosed bay, middle to outer shelf or even upper bathyal environment during ～18.7–4.53 Ma. The dominant Uvigerina spp. assemblage was characterized by low diversity and shallow infaunal to infaunal species, indicating a warm, low–oxygenation and eutrophic conditions since the Early Miocene to MMCO(～18.7–14.24 Ma). An abrupt sea level drop and significant faunal changes were recorded during 14.24–13.41 Ma, suggesting development of the East Antarctic Ice Sheets, which resulted in a drop of sea level and change in benthic foraminiferal assemblages along the shallow water shelf. Beyond the Uvigerina spp.assemblage, the Cibicides spp. assemblage became important during the middle–late Middle Miocene(14.24–11.54 Ma). This assemblage was dominated by epifaunal species with relative high diversity, suggesting high–energy, high–oxygenation and oligotrophic conditions with episodic supply of organic food. The dominant Cibicidoides spp. assemblage with high diversity, indicates a mesotrophic conditions with relative high–oxygen content during the Late Miocene to Pliocene(11.54–4.53 Ma). The appearance and continuous occurrence of Ammonia spp. and Pseudorotalia spp. since 10.02 Ma, may reflect the influence of the Kuroshio Current.展开更多
Compared to other Mo provinces,few studies focused on the South China Mo Province(SCMP),especially for Early Cretaceous Mo mineralization.The Lufeng porphyry Mo deposit in the SCMP is characterized by disseminated and...Compared to other Mo provinces,few studies focused on the South China Mo Province(SCMP),especially for Early Cretaceous Mo mineralization.The Lufeng porphyry Mo deposit in the SCMP is characterized by disseminated and veinlet-type mineralization in granite porphyry,gneiss,and rhyolite.In this study,six molybdenite samples yield a Re–Os isochron age of 108.0±1.8 Ma,which is consistent with the zircon U–Pb age of the granite porphyry(108.4±0.8 Ma).The coincidence of magmatic and hydrothermal activities indicates that Mo mineralization was associated with the intrusion of granite porphyry during the late Early Cretaceous.A compilation of U–Pb and Re–Os chronological data suggests that an extensive and intensive Mo mineralization event occurred in the SCMP during the late Early Cretaceous.The marked difference in molybdenite Re contents between Cu-bearing(85–536 ppm)and Cu-barren(1.3–59 ppm)Mo deposits of the late Early Cretaceous indicates that the ore-forming materials were derived from strong crust–mantle interactions.Together with regional petrological and geochemical data,this study suggests that late Early Cretaceous Mo mineralization in the SCMP occurred in an extensional setting associated with the roll-back of the Paleo-Pacific slab.展开更多
An incomplete dinosaur skeleton,including a partial skull,recently discovered from the Lower Jurassic Lufeng Formation of Yunnan,China,is here reported.Apart from its small size,little anatomical evidence supports,a p...An incomplete dinosaur skeleton,including a partial skull,recently discovered from the Lower Jurassic Lufeng Formation of Yunnan,China,is here reported.Apart from its small size,little anatomical evidence supports,a priori,the non-adult status of this new sauropodomorph specimen but osteohistological analyses suggest that it is a fast-growing juvenile.This specimen represents only the second occurrence of a juvenile non-sauropodan sauropodomorph in the Lufeng Basin.The anatomy of the new specimen does not match that of other Lower Jurassic immature specimens;although cranial material is preserved,it does not display the diagnostic characters of early sauropodomorphs from the same horizon,namely Lufengosaurus,Yizhousaurus and Yunnanosaurus.Our phylogenetic analysis places the new specimen in a position relatively distant from other Chinese sauropodomorphs,and corroborates the anatomical evidence showing it is not referable to any known species already excavated in Yunnan.This result is interpreted with caution considering that ontogeny affects phylogenetic reconstruction.A thorough comparison with adult forms,taking into account ontogenyrelated characters,suggests that this Lufeng juvenile might represent a previously unknown species of early sauropodomorph.展开更多
The element geochemical characteristics and diagenetic alteration products of tuffaceous components in sandstone reservoirs of Paleogene Wenchang Formation in typical subsags of the Huizhou-Lufeng area of the Zhu I De...The element geochemical characteristics and diagenetic alteration products of tuffaceous components in sandstone reservoirs of Paleogene Wenchang Formation in typical subsags of the Huizhou-Lufeng area of the Zhu I Depression,Pearl River Mouth Basin,were identified through microscopic analysis and quantitative analysis of main and trace elements.The impacts of dissolution of different tuffaceous components on physical properties of reservoirs were discussed through quantitative characterization of reservoir physical properties.The results show that there are mainly four types of tuffaceous components in the study area,which are acidic,intermediate,basic and alkaline tuffaceous components.The acidic tuffaceous components evolved in a process of strong alteration and weak dissolution of alteration products,with a large amount of kaolinite precipitated during alteration to disenable the improvement of porosity and permeability.The intermediate and alkaline tuffaceous components evolved in a process of strong dissolution of tuffaceous components and strong alteration of residual tuffaceous components;the dissolution of tuffaceous components created intergranular pores,but the alteration products such as autogenic quartz,apatite and illite deteriorated the pore structure;ultimately,the dissolution of tuffaceous components resulted in the increase of porosity but no increase of permeability of the reservoir.The basic tuffaceous components dominantly evolved in a process of dissolution of tuffaceous components to strong dissolution of alteration products;both tuffaceous components between particles and laumontite generated from alteration can be strongly dissolved to create pores;thus,the dissolution of tuffaceous components can significantly increase the physical properties of the reservoir.展开更多
Based on the data on petrology and geochemisty for the Jijie alkaline-ultrabasic intrusive rock complex, this paper, by means of correlation, suggested that the average composition of melteigites with 10% olivine adde...Based on the data on petrology and geochemisty for the Jijie alkaline-ultrabasic intrusive rock complex, this paper, by means of correlation, suggested that the average composition of melteigites with 10% olivine added (Fo=86) can be considered as the composition of the primary magma of the Jijie complex. This magma, whose composition is estimated from the incompatible element P2O5, was produced by 3%±partial melting of pyrolites. The results of Petrological Mixing Calculating showed that the mantle-source rocks of the Jijie complex are obviously depleted in incompatible elements.展开更多
珠江口盆地陆丰凹陷地区水体相对较浅,地势相对平坦,该区珠江组地层普遍发育两套高速灰岩地层,海面、海底、灰岩层上下强烈的阻抗差形成的强反射系数界面极易形成较强能量的多次波,加之浅水地区形成的短周期多次波与有效反射混叠,导致...珠江口盆地陆丰凹陷地区水体相对较浅,地势相对平坦,该区珠江组地层普遍发育两套高速灰岩地层,海面、海底、灰岩层上下强烈的阻抗差形成的强反射系数界面极易形成较强能量的多次波,加之浅水地区形成的短周期多次波与有效反射混叠,导致浅中深地层均受到多次波影响,大大增加了地震解释的多解性。该区独特的地质特点导致多次波能量强、类型复杂,常规方法难以有效进行压制。基于该区地质特点,以盆地东部的陆丰15洼缓坡带为例,采用了针对性的浅水区组合多次波压制方法,即:首先使用基于水层模型的多次波消除法(MWD,Model Shallow Water Demultiple)压制水层相关多次波尤其是短周期多次波,然后通过三维表面相关多次波衰减法(3D SRME,Surface Related Multiple Elimination)压制水面相关长周期多次波尤其是与灰岩界面相关的多次波及部分层间多次波,最后在叠前时间偏移后共成像点道集上用高分辨率Radon变换压制残余多次波。研究结果表明:MWD+3D SRME+Radon串联组合法能够有效压制水层短周期多次波和灰岩界面相关的长周期多次波以及部分层间多次波等,显著提高了地震资料信噪比和成像质量,为类似地质背景的地区提供了重要的借鉴意义。展开更多
文摘A skull and a series of associated cervical vertebrae （ZLJ0112） discovered from the Lower Lufeng Formation （Lower Jurassic） are determined as a juvenile specimen of Lufengosaurus huenei Young 1941 based on amended autapomorphies. Differences between ZLJ0112 and the holotype （subadult specimen） are considered as ontogenetic characteristic changes of L. huenei. Since some of these differences are present in other prosauropod dinosaurs （i.e., forms of the maxillary vascular foramen are irregular; the frontal contribution to the dorsal margin of the orbit is substantial; the frontal contribution to the supratemporal fossa is absent; the supratemporal fenestra is visible in lateral view; the supraoccipital inclined at 75 degrees; the parasphenoid rostrum lies level with the occipital condyle; the retroarticular process is short; the axial postzygapophysis project caudally beyond the end of the centrum） they may be common ontogenetic changes in prosauropod dinosaurs.
文摘This paper is concerned with the geochemical features of major elements, transitionmetal elements, large ion lithophile elements, rare-earth elements and Sr isotopes in alkaline-ul-trabasic rocks in the Jijie complex of Lufeng, Yunnan Province, which is located in southernSichuan-Yunnan rift zone, one of Luoci alkaline-ultrabasic complexes in central Ynnnan.Moreover, its origin pertaining primary magma, magma soure region, fractional crystallization,etc. are also discussed in the present paper.
基金supported by grants from the Canadian Museum of Nature and the National Science and Engineering Research Counsel of Canada (Grant No:203091-98).
文摘A new theropod dinosaur, Shidaisaurusjinae gen. et sp. nov., has been described on the basis of an incomplete skeleton. The specimen was found near the base of the Upper Lufeng Formation （early Middle Jurassic） in Yunnan, China. It is the first theropod dinosaur from the Middle Jurassic of Yunnan. Shidaisaurus jinae is distinguishable from other Jurassic theropods by certain features from the braincase, axis, and pelvic girdle. The absence of any pleurocoels in the axis or in any anterior dorsal vertebrae suggests that the new Lufeng theropod is relatively primitive and more plesiomorphic than most of the Middle to Late Jurassic theropods from China. Most Chinese taxa of Jurassic theropod dinosaurs have not been well described; a further detailed study will be necessary for us to determine their phylogenetic relationships with Shidaisaurusjinae.
基金The National Natural Science Foundation of China under contract No.91328201
文摘The Miocene epoch marks the most crucial period during the Cenozoic cooling trend, characterized by the Middle Miocene Climatic Optimum(MMCO) and a series of short–lived cooling events(Miocene isotope events).To understand the paleoenvironmental evolution along the shallow water shelf in the South China Sea during the Miocene, the benthic foraminiferal assemblage and total organic carbon content(TOC) were analyzed at Hole LF14 located in the Lufeng Sag, northern South China Sea. Three benthic foraminiferal assemblages(e.g., the Uvigerina spp. assemblage, the Cibicides spp. assemblage, and the Cibicidoides spp. assemblage), corresponding to different watermass conditions, were recognized based on Q–mode factor analysis. Early studies suggested that Hole LF14 was deposited under semienclosed bay, middle to outer shelf or even upper bathyal environment during ～18.7–4.53 Ma. The dominant Uvigerina spp. assemblage was characterized by low diversity and shallow infaunal to infaunal species, indicating a warm, low–oxygenation and eutrophic conditions since the Early Miocene to MMCO(～18.7–14.24 Ma). An abrupt sea level drop and significant faunal changes were recorded during 14.24–13.41 Ma, suggesting development of the East Antarctic Ice Sheets, which resulted in a drop of sea level and change in benthic foraminiferal assemblages along the shallow water shelf. Beyond the Uvigerina spp.assemblage, the Cibicides spp. assemblage became important during the middle–late Middle Miocene(14.24–11.54 Ma). This assemblage was dominated by epifaunal species with relative high diversity, suggesting high–energy, high–oxygenation and oligotrophic conditions with episodic supply of organic food. The dominant Cibicidoides spp. assemblage with high diversity, indicates a mesotrophic conditions with relative high–oxygen content during the Late Miocene to Pliocene(11.54–4.53 Ma). The appearance and continuous occurrence of Ammonia spp. and Pseudorotalia spp. since 10.02 Ma, may reflect the influence of the Kuroshio Current.
基金the Postdoctoral Science Foundation of China (No. 2018M630203)National Natural Science Foundation of China (Grant No. 41502090)
文摘Compared to other Mo provinces,few studies focused on the South China Mo Province(SCMP),especially for Early Cretaceous Mo mineralization.The Lufeng porphyry Mo deposit in the SCMP is characterized by disseminated and veinlet-type mineralization in granite porphyry,gneiss,and rhyolite.In this study,six molybdenite samples yield a Re–Os isochron age of 108.0±1.8 Ma,which is consistent with the zircon U–Pb age of the granite porphyry(108.4±0.8 Ma).The coincidence of magmatic and hydrothermal activities indicates that Mo mineralization was associated with the intrusion of granite porphyry during the late Early Cretaceous.A compilation of U–Pb and Re–Os chronological data suggests that an extensive and intensive Mo mineralization event occurred in the SCMP during the late Early Cretaceous.The marked difference in molybdenite Re contents between Cu-bearing(85–536 ppm)and Cu-barren(1.3–59 ppm)Mo deposits of the late Early Cretaceous indicates that the ore-forming materials were derived from strong crust–mantle interactions.Together with regional petrological and geochemical data,this study suggests that late Early Cretaceous Mo mineralization in the SCMP occurred in an extensional setting associated with the roll-back of the Paleo-Pacific slab.
基金Support for this research is from the Double First-Class joint program of Science&Technology Department of Yunnan and Yunnan University(2018FY001-005)the China-Myanmar Joint Laboratory for Ecological and Environmental Conservation+1 种基金the National Natural Science Foundation of China(grant number 41688103)funded by the China Postdoctoral Science Foundation。
文摘An incomplete dinosaur skeleton,including a partial skull,recently discovered from the Lower Jurassic Lufeng Formation of Yunnan,China,is here reported.Apart from its small size,little anatomical evidence supports,a priori,the non-adult status of this new sauropodomorph specimen but osteohistological analyses suggest that it is a fast-growing juvenile.This specimen represents only the second occurrence of a juvenile non-sauropodan sauropodomorph in the Lufeng Basin.The anatomy of the new specimen does not match that of other Lower Jurassic immature specimens;although cranial material is preserved,it does not display the diagnostic characters of early sauropodomorphs from the same horizon,namely Lufengosaurus,Yizhousaurus and Yunnanosaurus.Our phylogenetic analysis places the new specimen in a position relatively distant from other Chinese sauropodomorphs,and corroborates the anatomical evidence showing it is not referable to any known species already excavated in Yunnan.This result is interpreted with caution considering that ontogeny affects phylogenetic reconstruction.A thorough comparison with adult forms,taking into account ontogenyrelated characters,suggests that this Lufeng juvenile might represent a previously unknown species of early sauropodomorph.
基金Supported by the China National Natural Science Foundation(41872140)Taishan Scholars and Young Experts Project(201909061)+1 种基金Qingdao Marine Science and Technology Pilot Special Fund for National Laboratory in Shandong Province(2021QNLM020001)Central University Innovation Fund(20CX06067A).
文摘The element geochemical characteristics and diagenetic alteration products of tuffaceous components in sandstone reservoirs of Paleogene Wenchang Formation in typical subsags of the Huizhou-Lufeng area of the Zhu I Depression,Pearl River Mouth Basin,were identified through microscopic analysis and quantitative analysis of main and trace elements.The impacts of dissolution of different tuffaceous components on physical properties of reservoirs were discussed through quantitative characterization of reservoir physical properties.The results show that there are mainly four types of tuffaceous components in the study area,which are acidic,intermediate,basic and alkaline tuffaceous components.The acidic tuffaceous components evolved in a process of strong alteration and weak dissolution of alteration products,with a large amount of kaolinite precipitated during alteration to disenable the improvement of porosity and permeability.The intermediate and alkaline tuffaceous components evolved in a process of strong dissolution of tuffaceous components and strong alteration of residual tuffaceous components;the dissolution of tuffaceous components created intergranular pores,but the alteration products such as autogenic quartz,apatite and illite deteriorated the pore structure;ultimately,the dissolution of tuffaceous components resulted in the increase of porosity but no increase of permeability of the reservoir.The basic tuffaceous components dominantly evolved in a process of dissolution of tuffaceous components to strong dissolution of alteration products;both tuffaceous components between particles and laumontite generated from alteration can be strongly dissolved to create pores;thus,the dissolution of tuffaceous components can significantly increase the physical properties of the reservoir.
文摘Based on the data on petrology and geochemisty for the Jijie alkaline-ultrabasic intrusive rock complex, this paper, by means of correlation, suggested that the average composition of melteigites with 10% olivine added (Fo=86) can be considered as the composition of the primary magma of the Jijie complex. This magma, whose composition is estimated from the incompatible element P2O5, was produced by 3%±partial melting of pyrolites. The results of Petrological Mixing Calculating showed that the mantle-source rocks of the Jijie complex are obviously depleted in incompatible elements.
文摘珠江口盆地陆丰凹陷地区水体相对较浅,地势相对平坦,该区珠江组地层普遍发育两套高速灰岩地层,海面、海底、灰岩层上下强烈的阻抗差形成的强反射系数界面极易形成较强能量的多次波,加之浅水地区形成的短周期多次波与有效反射混叠,导致浅中深地层均受到多次波影响,大大增加了地震解释的多解性。该区独特的地质特点导致多次波能量强、类型复杂,常规方法难以有效进行压制。基于该区地质特点,以盆地东部的陆丰15洼缓坡带为例,采用了针对性的浅水区组合多次波压制方法,即:首先使用基于水层模型的多次波消除法(MWD,Model Shallow Water Demultiple)压制水层相关多次波尤其是短周期多次波,然后通过三维表面相关多次波衰减法(3D SRME,Surface Related Multiple Elimination)压制水面相关长周期多次波尤其是与灰岩界面相关的多次波及部分层间多次波,最后在叠前时间偏移后共成像点道集上用高分辨率Radon变换压制残余多次波。研究结果表明:MWD+3D SRME+Radon串联组合法能够有效压制水层短周期多次波和灰岩界面相关的长周期多次波以及部分层间多次波等,显著提高了地震资料信噪比和成像质量,为类似地质背景的地区提供了重要的借鉴意义。
