Water yield, water supply and quality, wildlife habitat, and ecosystem productivity and services are important societal concerns for natural resource management in the 21st century. Watershed-scale ecohydrologic studi...Water yield, water supply and quality, wildlife habitat, and ecosystem productivity and services are important societal concerns for natural resource management in the 21st century. Watershed-scale ecohydrologic studies can provide needed context for addressing complex spatial and temporal dynamics of these functions and services. This study was conducted on the 5240 ha Turkey Creek watershed (WS 78) draining a 3rd order stream on the Santee Experimental Forest within the South Carolina Atlantic Coastal Plain, USA. The study objectives were to present the hydrologic characteristics of this relatively undisturbed, except by a hurricane (Hugo, 1989), forested water-shed and to discuss key elements for watershed management, including water resource assessment (WRM), modeling integrated water resources management, environmental assessment, land use planning, social impact assessment, and information management. Runoff coefficients, flow duration curves, flood and low flow frequency curves, surface and ground water yields were assessed as elements of the WRM. Results from the last 10 years of interdisciplinary studies have also advanced the understanding of coastal ecohydrologic characteristics and processes, water balance, and their modeling including the need of high resolution LiDAR data. For example, surface water dynamics were shown to be regulated primarily by the water table, dependent upon pre- cipitation and evapotranspiration (ET). Analysis of pre- and post-Hugo streamflow data showed somewhat lower but insignificant (α = 0.05) mean annual flow but increased frequency of larger flows for the post-Hugo compared with the pre-Hugo level. However, there was no significant difference in mean annual ET, potentially indicating the resiliency of this coastal forest. Although the information from this study may be useful for comparison of coastal ecohydrologic issues, it is becoming increasingly clear that multi-site studies may be warranted to understand these complex systems in the face of climate change, sea level rise, and increasing development in coastal regions.展开更多
In regions with unpredictable rainfall and limited water supply,it’s crucial to pinpoint areas with high potential for groundwater and find the best spots for groundwater resource development.This study utilizes the ...In regions with unpredictable rainfall and limited water supply,it’s crucial to pinpoint areas with high potential for groundwater and find the best spots for groundwater resource development.This study utilizes the Analytic Hierarchy Process(AHP)in combination with Geographic Information Systems(GIS)to evaluate the potential groundwater zones in the Gombora watershed within the Omo Gibe basin in Ethiopia.Combining these two tools provided a detailed map showing potential groundwater areas.These zones are determined based on various thematic maps containing information about geology,soil texture,lineament density,slope,land use,and drainage density.The AHP method combines these data layers by assigning weights to each layer based on its importance for groundwater recharge.These weighted layers are then overlaid using a GIS platform to produce a conclusive map of potential groundwater areas.The groundwater potential within the watershed was qualitatively divided into five categories with area coverages of very good(1.6%),good(7.4%),moderate(21.4%),poor(51.6%),and very poor(17.9%)of thewatershed area.The accuracy of the groundwater potential zones was evaluated using the receiver operating characteristic(ROC)curve and the area under the curve(AUC),producing good results(AUC=75.5%).This research has shown that integrating AHP with GIS can effectively pinpoint potential groundwater zones.Additionally,the findings could play a key role in determining suitable locations for new groundwater wells and supplying valuable insights to decision-makers to aid in planning and implementing sustainable strategies for managing groundwater resources in the watershed.展开更多
The Zhaojue(ZJ)tracksites represent multiple steeply-inclined,track-bearing exposures in the clastic Feitianshan Formation of Sichuan Province that have been sequentially,excavated,mapped,expanded and destroyed,by qua...The Zhaojue(ZJ)tracksites represent multiple steeply-inclined,track-bearing exposures in the clastic Feitianshan Formation of Sichuan Province that have been sequentially,excavated,mapped,expanded and destroyed,by quarrying,erosion or collapse,for almost three decades.The quarried area extends for more almost 1.0 km from north to south and-0.5 km from east to west.Four important track-bearing surfaces have been identified and identified as ZJ-Ⅰ,ZJ-Ⅱ,ZJ-ⅡN and ZJ-Ⅲ,some of which are newly exposed surfaces or expanded surfaces that were previously partially described.Others represent surfaces lost since they were first reported in papers published in 2014-2016.The ZJ-Ⅱ site represents a hugely expanded continuation of a much smaller track-bearing surface described in 2014.It was mapped using drone technology,and now represents the largest tracksite in China,with a minimum count of 933 recognizable tracks,and the longest recorded sauropod and ornithopod trackways from China(-80 m and-52 m respectively),which also reveal a pronounced change in the direction of trackmaker movement.The ZJ-Ⅱ surface represents the best Zhaojue paleo-census sample giving a count of 68 individuals from 61 trackways(37 ornithopod,10 theropod,14 sauropod)and isolated tracks(representing 7 individuals).Thus,ornithopods(both large and small trackmakers)represent-54%of the total number of trackways.The smaller ZJ-Ⅲ surface was mapped using traditional methods,and reveals at least 6 ornithopod-and 4 theropod trackways.Both the ZJ-Ⅱ and ZJ-Ⅲ surfaces reveal parallel ornithopod trackways suggestive of social or gregarious behavior.The combined data from all four Zhaojue surfaces reveal a total of 1928 tracks,and include a few previously reported pterosaurs and theropod swim tracks.The Zhaojue quarry complex provide a good example of multiple track-bearing sites(surfaces)that require long term study and monitoring to extract as much trackway data as possible before in situ physical evidence is lost.展开更多
Karst aquifers supply a significant fraction of the world's drinking water. These types of aquifers are alsohighly susceptible to pollution from the surface with recharge usually occurring through fractures and so...Karst aquifers supply a significant fraction of the world's drinking water. These types of aquifers are alsohighly susceptible to pollution from the surface with recharge usually occurring through fractures and solution openings at the bedrock surface. Thickness of the protective soil cover, macropores and openings within the soil cover, and the nature of the weathered bedrock surface all influence infiltration. Recharge openings at the bedrock surface, however, are often covered by unconsolidated sediments, resulting in the inadvertent placement of landfills, unregulated dump sites, tailing piles, waste lagoons and septic systems over recharge zones. In these settings surface geophysical surveys, calibrated by a few soil cores, could be employed to identify these recharge openings, and qualitatively assess the protection afforded by the soil cover. In a test of this hypothesis, geophysical measurements accurately predicted the thickness of unconsolidated deposits overlying karstic dolomite at a site about 100 km south of Chicago, Illinois. Zones of elevated electrical conductivity and high ground-penetrating radar (GPR) attenuation within the sediments coincided with subcropping solutionally-enlarged hydraulically active bedrock fractures. These fractures extend to over 12-m depth, as shown by 2-D inverted resistivity sections and soil coring. Anomalous electromagnetic (EM) conductivity and GPR response may be due to higher soil moisture above these enlarged fractures. An epikarstal conduit at 2.5-m depth was directly identified through a GPR survey. These results suggest that surface geophysical surveys are a viable tool for assessing the susceptibility of shallow karst aquifers to contamination.展开更多
This paper describes newly discovered dinosaur and crocodylomorph egg fragments from the Upper Cretaceous Sanshui and Dalangshan formations of the Sanshui Basin of Guangdong Province,southern China.Despite the absence...This paper describes newly discovered dinosaur and crocodylomorph egg fragments from the Upper Cretaceous Sanshui and Dalangshan formations of the Sanshui Basin of Guangdong Province,southern China.Despite the absence of macroscopic information,the eggshell specimens can be identified to the oofamilies Prismatoolithidae,Elongatoolithidae and Krokolithidae,and it is hypothesized that these three families of eggs correspond to troodontids,oviraptorids and crocodiloids,respectively.Comparison with egg fossils from Nanxiong Basin,Heyuan Basin and Ganzhou Basin highlights the similarity between these egg assemblages and those from Nanxiong Basin.The egg fossils found in the Sanshui and the Dalangshan for-mations enrich the known faunal types in the research area and facilitate further studies on the diversity of Late Cretaceous vertebrate assemblages in the Sanshui Basin.展开更多
The Jiaguan Formation and the underlying Feitianshan Formation(Lower Cretaceous) in Sichuan Province yield multiple saurischian(theropod–sauropod) dominated ichnofaunas. To date, a moderate diversity of six theropod ...The Jiaguan Formation and the underlying Feitianshan Formation(Lower Cretaceous) in Sichuan Province yield multiple saurischian(theropod–sauropod) dominated ichnofaunas. To date, a moderate diversity of six theropod ichnogenera has been reported, but none of these have been identified at the ichnospecies level. Thus, many morphotypes have common "generic" labels such as Grallator, Eubrontes, cf. Eubrontes or even "EubrontesMegalosauripus" morphotype. These morphotypes are generally more typical of the Jurassic, whereas other more distinctive theropod tracks(Minisauripus and Velociraptorichnus) are restricted to the Cretaceous. The new ichnospecies Eubrontes nobitai ichnosp nov. is distinguished from Jurassic morphotypes based on a very wellpreserved trackway and represents the first-named Eubrontes ichnospecies from the Cretaceous of Asia.展开更多
The Yucatan Peninsula’s groundwater is experiencing increases in degradation due to swelling population and tourism;yet little is known about sources and transport of contaminants in drinking water supplies. The kars...The Yucatan Peninsula’s groundwater is experiencing increases in degradation due to swelling population and tourism;yet little is known about sources and transport of contaminants in drinking water supplies. The karst allows for rapid transport of microbial and chemical contaminants to the subsurface, resulting in significantly increased potential for pollution of groundwater. The objective of this research is to determine the occurrence, source, and extent of fecal contamination in the Tulum region of the Peninsula. A multi-analytical approach was undertaken in impacted and unimpacted groundwater locations;measurements included physicochemical parameters, total coliform and E. coli, Bacteroides (human vs total) and caffeine. The results indicate a variation in geochemistry from impacted to protected sites. The total coliform and E. coli show fecal contamination is wide spread. However, the presence of human Bacteriodes and caffeine in the water in the Tulum well field indicates that the recent human activities next to the well field are impacting the drinking water supply. This project is an assessment of the area’s current water quality conditions and the probable impact that the aforementioned growth would have on the area’s water supply. By applying multiple source parameter measurements, including molecular microbiology and chemical indicators it was confirmed the extent of fecal contamination of human origin covered the entire sampling region.展开更多
A large number of Upper Cretaceous(Maastrichtian)dinosaur skeletal fossils have been found in the Nanxiong Basin and adjacent Ganzhou area,including those of theropods,sauropods and hadrosaurids.However,known dinosaur...A large number of Upper Cretaceous(Maastrichtian)dinosaur skeletal fossils have been found in the Nanxiong Basin and adjacent Ganzhou area,including those of theropods,sauropods and hadrosaurids.However,known dinosaur ichnoassemblages from the Nanxiong Basin partly indicate a different fauna,with dominating large-and medium-sized ornithopods,theropods,and pterosaurs(1,2)This is one of many known examples where trace and body fossil assemblages from the same formation or geologically discrete region show a different composition.Palecological and paleobiogeographical analyses therefore should consider data from both,before any conclusions can be drawn.Formations can be classified according to the relative degree of similarity or congruity(or difference/incongruity)between trace and body fossils into the 5 categories proposed by Lockley[3].展开更多
The formation factor relates bulk resistivity to pore fluid resistivity in porous materials. Understanding the formation factor is essential in using electrical and electromagnetic methods to monitor ieachate accumula...The formation factor relates bulk resistivity to pore fluid resistivity in porous materials. Understanding the formation factor is essential in using electrical and electromagnetic methods to monitor ieachate accumulations and movements both within and around landfills. Specifically, the formation factor allows leachate resistivity, the degree of saturation, and, possibly, even the hydraulic conductivity of the waste to be estimated from non-invasive surface measurements. In this study, apparent formation factors are computed for three landfills with different types of waste as well as sediments contaminated by landfill leachate. Resistivity soundings at the closed Mallard North landfill in suburban Chicago （Illinois, USA） mapped leachate surfaces that were confirmed by monitoring wells. The resistivity of leachate-saturated waste from resistivity sounding inversions was then divided by the leachate resistivity values measured in-situ to compute apparent formation factors （Fa） ranging from 1.6 to 4.9. A global Fa of 3.0±1.9 was computed for the entire monitored portion of this landfill. At a nearby mixed laboratory waste landfill, a 2D inverted resistivity section was used to compute an Fa of 2.9. Finally, a distinctly different Fa value of 10.6±2.8 was computed for leachate-saturated retorted oil shale wastes north of Maoming （茂名）, Guangdong （广东） Province, China. Shallow aquifers in the Laohuling （老虎岭） Formation near this landfill are polluted by acidic leachate containing heavy metals and organic compounds. The Fa for aquifers containing contaminated groundwater fall in the same range as aquifers with normal groundwater, 1.7-3.9. However, models from inverted sounding curves over these contaminated areas exhibit unusually low resistivity layers, which may be diagnostic of contamination.展开更多
Tracks previously examined between 2002 and 2015 from an incompletely-studied,and now partially lost tracksite site in the Santai Formation of Shandong Province were restudied based on new ex-cavations of additional s...Tracks previously examined between 2002 and 2015 from an incompletely-studied,and now partially lost tracksite site in the Santai Formation of Shandong Province were restudied based on new ex-cavations of additional surfaces.In contrast to the previous reports of tridactyl tracks,including Grallator,the present study discovered an additional assemblage of unequivocal pterosaur tracks(Pteraichnus)and a possible didactyl deinonychosaurian track.The age of the Santai Formation is controversial but it is probably Late Jurassic,which corresponds to the epoch when pterosaur tracks appear worldwide.Age interpretations,based on palynology and isotopic data,tentatively suggests an earlier Middle-Late Jurassic age and might suggest that the pterosaurian tracks are as old or somewhat older than any previously reported.展开更多
Understanding the impact of meltwater discharge during the final stage of the Laurentide Ice Sheet(LIS)has important implications for predicting sea level rise and climate change.Here we present a highresolution ice-c...Understanding the impact of meltwater discharge during the final stage of the Laurentide Ice Sheet(LIS)has important implications for predicting sea level rise and climate change.Here we present a highresolution ice-core isotopic record from the central Tibetan Plateau(TP),where the climate is sensitive to the meltwater forcing,and explore possible signals of the climate response to potential LIS meltwater discharges in the early to mid-Holocene.The record shows four abrupt large fluctuations during the 7–9 ka BP(kiloannum before present),reflecting large shifts of the mid-latitude westerlies and the Indian summer monsoon(ISM)over this period,and they corresponded to possible LIS freshwater events documented in other paleoclimate records.Our study suggests that multiple rapid meltwater discharge events might have occurred during the final stage of LIS.The finding implies the possibility of rapid sea level rise and unstable climate in the transition zone between the mid-latitude westerlies and the ISM due to fast polar ice retreat under the anthropogenic global warming.展开更多
文摘Water yield, water supply and quality, wildlife habitat, and ecosystem productivity and services are important societal concerns for natural resource management in the 21st century. Watershed-scale ecohydrologic studies can provide needed context for addressing complex spatial and temporal dynamics of these functions and services. This study was conducted on the 5240 ha Turkey Creek watershed (WS 78) draining a 3rd order stream on the Santee Experimental Forest within the South Carolina Atlantic Coastal Plain, USA. The study objectives were to present the hydrologic characteristics of this relatively undisturbed, except by a hurricane (Hugo, 1989), forested water-shed and to discuss key elements for watershed management, including water resource assessment (WRM), modeling integrated water resources management, environmental assessment, land use planning, social impact assessment, and information management. Runoff coefficients, flow duration curves, flood and low flow frequency curves, surface and ground water yields were assessed as elements of the WRM. Results from the last 10 years of interdisciplinary studies have also advanced the understanding of coastal ecohydrologic characteristics and processes, water balance, and their modeling including the need of high resolution LiDAR data. For example, surface water dynamics were shown to be regulated primarily by the water table, dependent upon pre- cipitation and evapotranspiration (ET). Analysis of pre- and post-Hugo streamflow data showed somewhat lower but insignificant (α = 0.05) mean annual flow but increased frequency of larger flows for the post-Hugo compared with the pre-Hugo level. However, there was no significant difference in mean annual ET, potentially indicating the resiliency of this coastal forest. Although the information from this study may be useful for comparison of coastal ecohydrologic issues, it is becoming increasingly clear that multi-site studies may be warranted to understand these complex systems in the face of climate change, sea level rise, and increasing development in coastal regions.
基金supported by the National Science Foundation-Hydrologic Science Program。
文摘In regions with unpredictable rainfall and limited water supply,it’s crucial to pinpoint areas with high potential for groundwater and find the best spots for groundwater resource development.This study utilizes the Analytic Hierarchy Process(AHP)in combination with Geographic Information Systems(GIS)to evaluate the potential groundwater zones in the Gombora watershed within the Omo Gibe basin in Ethiopia.Combining these two tools provided a detailed map showing potential groundwater areas.These zones are determined based on various thematic maps containing information about geology,soil texture,lineament density,slope,land use,and drainage density.The AHP method combines these data layers by assigning weights to each layer based on its importance for groundwater recharge.These weighted layers are then overlaid using a GIS platform to produce a conclusive map of potential groundwater areas.The groundwater potential within the watershed was qualitatively divided into five categories with area coverages of very good(1.6%),good(7.4%),moderate(21.4%),poor(51.6%),and very poor(17.9%)of thewatershed area.The accuracy of the groundwater potential zones was evaluated using the receiver operating characteristic(ROC)curve and the area under the curve(AUC),producing good results(AUC=75.5%).This research has shown that integrating AHP with GIS can effectively pinpoint potential groundwater zones.Additionally,the findings could play a key role in determining suitable locations for new groundwater wells and supplying valuable insights to decision-makers to aid in planning and implementing sustainable strategies for managing groundwater resources in the watershed.
基金funded by the National Natural Science Foundation of China(Grant No.41772008,41772023)the 111 project(Grant No.B20011).
文摘The Zhaojue(ZJ)tracksites represent multiple steeply-inclined,track-bearing exposures in the clastic Feitianshan Formation of Sichuan Province that have been sequentially,excavated,mapped,expanded and destroyed,by quarrying,erosion or collapse,for almost three decades.The quarried area extends for more almost 1.0 km from north to south and-0.5 km from east to west.Four important track-bearing surfaces have been identified and identified as ZJ-Ⅰ,ZJ-Ⅱ,ZJ-ⅡN and ZJ-Ⅲ,some of which are newly exposed surfaces or expanded surfaces that were previously partially described.Others represent surfaces lost since they were first reported in papers published in 2014-2016.The ZJ-Ⅱ site represents a hugely expanded continuation of a much smaller track-bearing surface described in 2014.It was mapped using drone technology,and now represents the largest tracksite in China,with a minimum count of 933 recognizable tracks,and the longest recorded sauropod and ornithopod trackways from China(-80 m and-52 m respectively),which also reveal a pronounced change in the direction of trackmaker movement.The ZJ-Ⅱ surface represents the best Zhaojue paleo-census sample giving a count of 68 individuals from 61 trackways(37 ornithopod,10 theropod,14 sauropod)and isolated tracks(representing 7 individuals).Thus,ornithopods(both large and small trackmakers)represent-54%of the total number of trackways.The smaller ZJ-Ⅲ surface was mapped using traditional methods,and reveals at least 6 ornithopod-and 4 theropod trackways.Both the ZJ-Ⅱ and ZJ-Ⅲ surfaces reveal parallel ornithopod trackways suggestive of social or gregarious behavior.The combined data from all four Zhaojue surfaces reveal a total of 1928 tracks,and include a few previously reported pterosaurs and theropod swim tracks.The Zhaojue quarry complex provide a good example of multiple track-bearing sites(surfaces)that require long term study and monitoring to extract as much trackway data as possible before in situ physical evidence is lost.
文摘Karst aquifers supply a significant fraction of the world's drinking water. These types of aquifers are alsohighly susceptible to pollution from the surface with recharge usually occurring through fractures and solution openings at the bedrock surface. Thickness of the protective soil cover, macropores and openings within the soil cover, and the nature of the weathered bedrock surface all influence infiltration. Recharge openings at the bedrock surface, however, are often covered by unconsolidated sediments, resulting in the inadvertent placement of landfills, unregulated dump sites, tailing piles, waste lagoons and septic systems over recharge zones. In these settings surface geophysical surveys, calibrated by a few soil cores, could be employed to identify these recharge openings, and qualitatively assess the protection afforded by the soil cover. In a test of this hypothesis, geophysical measurements accurately predicted the thickness of unconsolidated deposits overlying karstic dolomite at a site about 100 km south of Chicago, Illinois. Zones of elevated electrical conductivity and high ground-penetrating radar (GPR) attenuation within the sediments coincided with subcropping solutionally-enlarged hydraulically active bedrock fractures. These fractures extend to over 12-m depth, as shown by 2-D inverted resistivity sections and soil coring. Anomalous electromagnetic (EM) conductivity and GPR response may be due to higher soil moisture above these enlarged fractures. An epikarstal conduit at 2.5-m depth was directly identified through a GPR survey. These results suggest that surface geophysical surveys are a viable tool for assessing the susceptibility of shallow karst aquifers to contamination.
基金funded by the National Natural Science Foundation of China (No. 41888101)the 111project (No. B20011)the Fundamental Research Funds for the Central Universities (No. 265QZ201903)
文摘This paper describes newly discovered dinosaur and crocodylomorph egg fragments from the Upper Cretaceous Sanshui and Dalangshan formations of the Sanshui Basin of Guangdong Province,southern China.Despite the absence of macroscopic information,the eggshell specimens can be identified to the oofamilies Prismatoolithidae,Elongatoolithidae and Krokolithidae,and it is hypothesized that these three families of eggs correspond to troodontids,oviraptorids and crocodiloids,respectively.Comparison with egg fossils from Nanxiong Basin,Heyuan Basin and Ganzhou Basin highlights the similarity between these egg assemblages and those from Nanxiong Basin.The egg fossils found in the Sanshui and the Dalangshan for-mations enrich the known faunal types in the research area and facilitate further studies on the diversity of Late Cretaceous vertebrate assemblages in the Sanshui Basin.
基金supported by the National Natural Science Foundation of China(Grant No. 41772008)the 111 project,China (Grant No. B20011)the Fundamental Research Funds for Central Universities (Grant No.265QZ201903)。
文摘The Jiaguan Formation and the underlying Feitianshan Formation(Lower Cretaceous) in Sichuan Province yield multiple saurischian(theropod–sauropod) dominated ichnofaunas. To date, a moderate diversity of six theropod ichnogenera has been reported, but none of these have been identified at the ichnospecies level. Thus, many morphotypes have common "generic" labels such as Grallator, Eubrontes, cf. Eubrontes or even "EubrontesMegalosauripus" morphotype. These morphotypes are generally more typical of the Jurassic, whereas other more distinctive theropod tracks(Minisauripus and Velociraptorichnus) are restricted to the Cretaceous. The new ichnospecies Eubrontes nobitai ichnosp nov. is distinguished from Jurassic morphotypes based on a very wellpreserved trackway and represents the first-named Eubrontes ichnospecies from the Cretaceous of Asia.
文摘The Yucatan Peninsula’s groundwater is experiencing increases in degradation due to swelling population and tourism;yet little is known about sources and transport of contaminants in drinking water supplies. The karst allows for rapid transport of microbial and chemical contaminants to the subsurface, resulting in significantly increased potential for pollution of groundwater. The objective of this research is to determine the occurrence, source, and extent of fecal contamination in the Tulum region of the Peninsula. A multi-analytical approach was undertaken in impacted and unimpacted groundwater locations;measurements included physicochemical parameters, total coliform and E. coli, Bacteroides (human vs total) and caffeine. The results indicate a variation in geochemistry from impacted to protected sites. The total coliform and E. coli show fecal contamination is wide spread. However, the presence of human Bacteriodes and caffeine in the water in the Tulum well field indicates that the recent human activities next to the well field are impacting the drinking water supply. This project is an assessment of the area’s current water quality conditions and the probable impact that the aforementioned growth would have on the area’s water supply. By applying multiple source parameter measurements, including molecular microbiology and chemical indicators it was confirmed the extent of fecal contamination of human origin covered the entire sampling region.
基金supported by the National Natural Science Foundation of China(41888101,41790455,41772008)the Fundamental Research Funds for the Central Universities(2652017215)+2 种基金the Funds of State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences(173127)SLB’s work on Qianzhousaurus was funded by National Science Foundation(NSF)Doctoral Dissertation Improvement Grants(DEB 1110357)the American Museum of Natural History Division of Paleontology,and Columbia University
文摘A large number of Upper Cretaceous(Maastrichtian)dinosaur skeletal fossils have been found in the Nanxiong Basin and adjacent Ganzhou area,including those of theropods,sauropods and hadrosaurids.However,known dinosaur ichnoassemblages from the Nanxiong Basin partly indicate a different fauna,with dominating large-and medium-sized ornithopods,theropods,and pterosaurs(1,2)This is one of many known examples where trace and body fossil assemblages from the same formation or geologically discrete region show a different composition.Palecological and paleobiogeographical analyses therefore should consider data from both,before any conclusions can be drawn.Formations can be classified according to the relative degree of similarity or congruity(or difference/incongruity)between trace and body fossils into the 5 categories proposed by Lockley[3].
基金supported by the National Natural Science Foundation of China (No. 40873076)Science & Technology Project of Guangdong Province (2KM06506S)+1 种基金the Environmental Protection Bureau of Maoming for funding the Maoming work and providing logistical support in the fieldThe Department of Geology and Environmental Geosciences, Graduate School, School of Liberal Arts and Sciences, Northern Illinois University, and Argonne National Laboratory provided support for the Mallard North project and provided travel support to China during a research sabbatical
文摘The formation factor relates bulk resistivity to pore fluid resistivity in porous materials. Understanding the formation factor is essential in using electrical and electromagnetic methods to monitor ieachate accumulations and movements both within and around landfills. Specifically, the formation factor allows leachate resistivity, the degree of saturation, and, possibly, even the hydraulic conductivity of the waste to be estimated from non-invasive surface measurements. In this study, apparent formation factors are computed for three landfills with different types of waste as well as sediments contaminated by landfill leachate. Resistivity soundings at the closed Mallard North landfill in suburban Chicago （Illinois, USA） mapped leachate surfaces that were confirmed by monitoring wells. The resistivity of leachate-saturated waste from resistivity sounding inversions was then divided by the leachate resistivity values measured in-situ to compute apparent formation factors （Fa） ranging from 1.6 to 4.9. A global Fa of 3.0±1.9 was computed for the entire monitored portion of this landfill. At a nearby mixed laboratory waste landfill, a 2D inverted resistivity section was used to compute an Fa of 2.9. Finally, a distinctly different Fa value of 10.6±2.8 was computed for leachate-saturated retorted oil shale wastes north of Maoming （茂名）, Guangdong （广东） Province, China. Shallow aquifers in the Laohuling （老虎岭） Formation near this landfill are polluted by acidic leachate containing heavy metals and organic compounds. The Fa for aquifers containing contaminated groundwater fall in the same range as aquifers with normal groundwater, 1.7-3.9. However, models from inverted sounding curves over these contaminated areas exhibit unusually low resistivity layers, which may be diagnostic of contamination.
基金the National Natural Science Foundation of China(No.41888101)the 111 project(B20011)the Fundamental Research Funds for Central Universities(265QZ201903).
文摘Tracks previously examined between 2002 and 2015 from an incompletely-studied,and now partially lost tracksite site in the Santai Formation of Shandong Province were restudied based on new ex-cavations of additional surfaces.In contrast to the previous reports of tridactyl tracks,including Grallator,the present study discovered an additional assemblage of unequivocal pterosaur tracks(Pteraichnus)and a possible didactyl deinonychosaurian track.The age of the Santai Formation is controversial but it is probably Late Jurassic,which corresponds to the epoch when pterosaur tracks appear worldwide.Age interpretations,based on palynology and isotopic data,tentatively suggests an earlier Middle-Late Jurassic age and might suggest that the pterosaurian tracks are as old or somewhat older than any previously reported.
基金supported by the National Natural Science Foundation of China(41830644,91837102,and 42021001)the Research Funds for the Frontiers Science Center for Critical Earth Material Cycling,Nanjing University+2 种基金the Fundamental Research Funds for the Central Universities(020914380103)the Collaborative Innovation Center of Climate Change of Jiangsu Provincethe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Understanding the impact of meltwater discharge during the final stage of the Laurentide Ice Sheet(LIS)has important implications for predicting sea level rise and climate change.Here we present a highresolution ice-core isotopic record from the central Tibetan Plateau(TP),where the climate is sensitive to the meltwater forcing,and explore possible signals of the climate response to potential LIS meltwater discharges in the early to mid-Holocene.The record shows four abrupt large fluctuations during the 7–9 ka BP(kiloannum before present),reflecting large shifts of the mid-latitude westerlies and the Indian summer monsoon(ISM)over this period,and they corresponded to possible LIS freshwater events documented in other paleoclimate records.Our study suggests that multiple rapid meltwater discharge events might have occurred during the final stage of LIS.The finding implies the possibility of rapid sea level rise and unstable climate in the transition zone between the mid-latitude westerlies and the ISM due to fast polar ice retreat under the anthropogenic global warming.
