Deep-water gravity depositional processes and evolution in arc systems have become topics of intense research focus in recent years.This study discusses the co-evolution of volcanism and deep-water gravity flow deposi...Deep-water gravity depositional processes and evolution in arc systems have become topics of intense research focus in recent years.This study discusses the co-evolution of volcanism and deep-water gravity flow deposits at the southern margin of the Junggar Basin,based on petrology,geochronology and geochemical analyses.The results show that a massive collapse of unstable sediments from the slope was triggered by volcanism,resulting in the formation of slumping gravity flows.The occurrence of volcanic beds in the slump deposits confirm that synchronous volcanism likely affected sediment instability,triggering gravity flows.The Th/Yb,Ta/Yb and Th/Ta elemental ratios,U-Pb ages of detrital zircons and paleocurrent directions indicate that the North Tianshan(NTS)island arc represents the provenance of the Qianxia Formation.Moreover,statistical data on the pyroclastic components in the gravity flow deposits reveal an intensity index of volcanism,indicating that volcanism is strongly related to gravity flow deposits,especially in terms of the type and distribution of the deposits.A model for volcanically-triggered deep-water gravity flow deposits is established,in order to provide a more in-depth understanding of the co-evolution of volcanism and gravity flow deposits within the depositional setting of the late Paleozoic NTS oceanic subduction margin in the Junggar Basin.展开更多
The development of technology and the demands of groups of interest for standardized digital geospatial information are increasing daily.The necessity for referred geospatial information,according to a Referencing Coo...The development of technology and the demands of groups of interest for standardized digital geospatial information are increasing daily.The necessity for referred geospatial information,according to a Referencing Coordinating System and European Standards,through a national GIS(Geographic Information System)system,requires a decision making of national and institutional importance.ASIG(State Authority for Geospatial Information)is the institution that administrates,implements,and maintains the NSDI(National Spatial Data Infrastructure).It is calculated that 80%of decision-making by public or private institutions uses geospatial data with a well-organized structure that enables efficiency.Thus,standardization of geospatial data by topic is one of the main objectives of implementing the NSDI in Albania.This is a complex task for the standard and the harmonization of geospatial data,which can be a good opportunity for professional awareness.This study shows in detail the methodology for the creation and implementation of data specification for geospatial information in Albania on the theme:Geology,adoption of the technical specification of the INSPIRE directive as well as the importance of ASIG as an institution that builds and maintains NSDI in Albania.展开更多
Venusian coronae are large(60-2600 km diameter)tectono-magmatic features characterized by quasi-circular graben-fissure systems and topographic features such as a central dome,central depression,circular rim or circular
Groundwater samples were evaluated throughout Turkana County(Kenya,East Africa)while looking for drinking water sources.Some samples showed high concentrations of fluoride with values in the range of 0.15–5.87 mg/L.A...Groundwater samples were evaluated throughout Turkana County(Kenya,East Africa)while looking for drinking water sources.Some samples showed high concentrations of fluoride with values in the range of 0.15–5.87 mg/L.Almost 50%of the samples exceeded the WHO and Kenyan potable water standard guideline value of 1.5 mg/L for drinking water quality.The hydrogeochemical studies revealed that the dominant cation in water is Na^(+)and the dominant anion is HCO_(3)^(-)resulting in Na-HCO_(3) type of groundwater,followed by Ca/Mg-HCO_(3) or Na-SO_(4) and Na-Cl in a few cases.Speciation modelling revealed that the groundwater is undersaturated with respect to gypsum and anhydrite,mostly undersaturated with respect to fluorite(6 samples are at equilibrium),and supersaturated or at equilibrium with respect to calcite(CaCO_(3)).Precipitation of calcite favours the dissolution of F-rich minerals in the alkaline medium.Simultaneously,groundwater is enriched with sodium and bicarbonate,probably as a result of chemical weathering of Na-feldspar.Investigated groundwater can be presumably used for drinking purposes from 17 wells,but a detailed investigation of other trace element concentrations is necessary.展开更多
The article considers the issue of the world cities in terms of sustainable development.The population has been increasing in such intensive rates never reached during the middle of the 20th century.The expansion of t...The article considers the issue of the world cities in terms of sustainable development.The population has been increasing in such intensive rates never reached during the middle of the 20th century.The expansion of the cities indicates,on the one hand,the growth of the world’s general socio-economic development,on the other hand,it raises a number of economic,social and environmental problems.The purpose of this paper is to analyze the current state and prospects of the world cities in terms of the sustainable development concept,to identify opportunities,threats,strengths and weaknesses of the world cities,to determine the role of cities in the con-temporary global world and consider further research of the world’s cities.The authors analyzed the world cities rankings and noted that highly developed cities have more chances to quickly implement the sustainable devel-opment concept compared to medium-sized cities due to larger financial resources.The authors built a SWOT analysis of the world cities transformation in terms of the sustainable development concept,identified strengths,weaknesses,opportunities and threats.According to the results of the SWOT analysis,the authors established that sustainable development of cities requires significant investments,particularly in the social sphere develop-ment,purification,and preservation of urban nature from the anthropogenic impacts.The research result is the systematization of the sustainable development criteria used in compiling the world cities rankings,determining the possibilities of the contemporary cities transition to the sustainable development concept.展开更多
Based on field outcrop data,the effects of cyclic change of astronomical orbit and volcanic activity on organic carbon accumulation during the Late Ordovician-Early Silurian in the Upper Yangtze area were studied usin...Based on field outcrop data,the effects of cyclic change of astronomical orbit and volcanic activity on organic carbon accumulation during the Late Ordovician-Early Silurian in the Upper Yangtze area were studied using cyclostratigraphic and geochemical methods.d13 C and chemical index of alteration(CIA)were used to filter the astronomical orbit parameters recorded in sediments.It is found that the climate change driven by orbital cycle controls the fluctuations of sea level at different scales,obliquity forcing climate changes drive thermohaline circulation(THC)of the ocean,and THC-induced bottom currents transport nutrient-laden water from high latitude regions to the surface water of low-latitude area.Hence,THC is the main dynamic mechanism of organic-carbon supply.The marine productivity indexes of Ba/Al and Ni/Al indicate that volcanic activities had limited effect on marine productivity but had great influences on organic carbon preservation efficiency in late Hirnantian(E4).Paleo-ocean redox environmental indicators Th/U,V/Cr and V/(V+Ni)show that there is a significant correlation between volcanism and oxygen content in Paleo-ocean,so it is inferred that volcanisms controlled the organic carbon preservation efficiency by regulating oxygen content in Paleo-ocean,and the difference in volcanism intensity in different areas is an important factor for the differential preservation efficiency of organic carbon.The organic carbon input driven by orbital cycle and the preservation efficiency affected by volcanisms worked together to control the enrichment of organic carbon in the Middle–Upper Yangtze region.展开更多
This paper aims to advance previous studies on the iron and manganese content in groundwater of Rrogozhina aquifer (western Albania) and to show the factors which control the content of both iron and manganese in gr...This paper aims to advance previous studies on the iron and manganese content in groundwater of Rrogozhina aquifer (western Albania) and to show the factors which control the content of both iron and manganese in groundwater of this aquifer. Rrogozhina aquifer represents an important groundwater source of the country whose relevance was highly increased during recent years because of the demographic expansion in this region. This is a typically multi-layered artesian aquifer which consists of sandstone and conglomerate with high heterogeneous permeability. The groundwater mostly belongs to HCO3-Mg-Ca hydrochemical type. The content of soluble iron and manganese in groundwater ranges from 0.004 mg/L to 0.7 mg/L, and from 0.0 mg/L to 1.147 mg/L, respectively. Deeper the groundwater occurs and longer the distance from the recharge zone, higher is the content of Fe2+ in groundwater due to gradual depletion of Oe in groundwater. The content of iron is higher than that WHO and EU recommended, which were 21% and 25% respectively, while the content of manganese were 17% and 23%, respectively. Abstraction of groundwater with high quantities by deeper wells would be accompanied by increase of dissolved iron and manganese content in groundwater which should be treated (with aeration) in order to decrease the content of these two elements in the water before using it.展开更多
The basement of the Romanian Carpathians is made of Neoproterozoic to early Paleozoic peri- Gondwanan terranes variably involved in the Variscan orogeny, similarly to other basement terrains of Europe. They were hardl...The basement of the Romanian Carpathians is made of Neoproterozoic to early Paleozoic peri- Gondwanan terranes variably involved in the Variscan orogeny, similarly to other basement terrains of Europe. They were hardly dismembered during the Alpine orogeny and traditionally have their own names in the three Carpathian areas. The Danubian domain of the South Carpathians comprises the Dragsan and Lainici-Paiius peri-Amazonian terranes. The Dragsan terrane originated within the ocean surrounding Rodinia and docked with Rodinia at -800 Ma. It does not contain Cadomian magmatism and consequently it is classified as an Avalonian extra-Cadomian terrane, The Lainici-Pfiius terrane is a Ganderian fragment strongly modified by Cadomian subduction-related magmatism, It is attached to the Moesia platform. The TisoviD terrane is an ophiolite that marks the boundary between Drfagsan and Lainici-Paius terranes. The other basement terranes of the Romanian Carpathians originated close to the Ordovician North- African orogen, as a result of the eastern Rheic Ocean opening and closure. Except for the Sebes-Lotru terrane that includes a lower metamorphic unit of Cadomian age, all the other terranes (Bretila, Tulghes, Negrisoara and Rebra in the East Carpathians, Somes, Biharia and Baia de Aries in the Apuseni mountains, Fagaras, Leaota, Carat and Pades in the South Carpathians) represent late Cambrian-Ordovician rock assemblages. Their provenance, is probably within paleo-nortbeast Africa, close to the Arabian-Nubian shield. The late Cambrian-Ordovician terranes are defined here as Carpathian-type terranes. According to their lithostratigraphy and origin, some are of continental margin magmatic arc setting, whereas others formed in rift and back-arc environment and closed to passive continental margin settings. In a paleo- geographic reconstruction, the continental margin magmatic arc terranes were first that drifted out, followed by the passive continental margin terranes with the back-arc terranes in their front. They accreted to Laurussia during the Variscan orogeny. Some of them (Sebes-Lotru in South Carpathians and Baia de Aries in Apuseni mountains) underwent eclogite-grade metamorphism. The Danubian terranes, the Bretila terrane and the Somes terrane were intruded by Variscan granitoids.展开更多
The Sinuiju Formation in Paekto-dong,Sinuiju City in the Democratic People's Republic of Korea has yielded Mesozoic nonmarine bivalve fossils,which is the first occurrence of such in the DPRK.Based on these fossil...The Sinuiju Formation in Paekto-dong,Sinuiju City in the Democratic People's Republic of Korea has yielded Mesozoic nonmarine bivalve fossils,which is the first occurrence of such in the DPRK.Based on these fossil specimens,a new Cretaceous bivalve assemblage,the Arguniella yanshanensis-Sphaerium anderssoni Assemblage is erected.This assemblage includes Arguniella yanshanensis,A.lingyuanensis and Sphaerium anderssoni and can be compared with the Jehol Biota.The age of the Sinuiju Formation is also clarified and on the basis of the bivalves and the presence of a Eosestheria–Ephemeropsis–Lycoptera(E–E–L)assemblage,the formation is not Upper Jurassic,but Lower Cretaceous in age.展开更多
Note: Items in Episodes' Classic Paper series normally analyze a single paper of major importance in the history of geosciences. The present contribution examines the book in which Milankovich summed up his life wor...Note: Items in Episodes' Classic Paper series normally analyze a single paper of major importance in the history of geosciences. The present contribution examines the book in which Milankovich summed up his life work. One of the few Serbian scientists of worldwide renown, Milutin Milankovich, was professor of applied mathematics at Belgrade University. He was born in 1879 in Dalj, near Osjek (today in Croatia). He studied construction engineering in Vienna, graduated in 1902 and gained his PhD in 1904. After a brief but successful engineering practice in Vienna, he moved to Belgrade University. During his thirty years of work there he produced: a mathematical theory of the Earth's climate (1920); his astronomic theory of climatic changes (1930, 1938, 1938a); and his theory of the secular wandering of the Earth's poles (1933). He retired in 1955 and died in Belgrade in 1958.展开更多
An association of organic-walled microfossils consisting of filamentous cyanobacteria, algal coenobia and acanthomorphic acritarch have been documented from non-calcareous claystones and mudstones of the Pepper Mounta...An association of organic-walled microfossils consisting of filamentous cyanobacteria, algal coenobia and acanthomorphic acritarch have been documented from non-calcareous claystones and mudstones of the Pepper Mountains Shale Formation(PMSF), located in its stratotype area in the Pepper Mountains, which are part of the Holy Cross Mountains in Poland. These sediments represent the oldest strata of the ?ysogóry Unit, deposited on the edge of the East European Craton(Baltica). Non-branched, ribbon-like and thread-like cyanobacteria trichomes exhibit morphological similarities to families Nostocaceae and Oscillatoriaceae. Cells assembled in rounded to irregular clusters of monospecific agglomerations represent multicellular algal coenobia, attributed to the family Scenedesmaceae. The co-occurrence of acritarchs belonging to species as Eliasum llaniscum, Cristallinium ovillense and Estiastra minima indicates that the studied material corresponds to the lower Middle Cambrian. Deposition of the PMSF took place in shallow marine environment, influenced by periodical freshwater inputs. The varying degree of coloration of organic-walled microfossils is interpreted in this study as factor indication of possible different source of their derivation. Dark brown walls of cells assembled in algal coenobia might have sustained previous humification in humid, terrestrial environments, which preceded their river transport into the sea together with nutrients, causing occasional blooms of cyanobacteria in the coastal environment and the final deposition of both groups of organisms in marine deposits.展开更多
Extremely abundant PGE-minerals(PGM)hosted in chromitites from the Veria ophiolite complex in Macedonia(N.Greece)may be unique among ophiolite complexes.This study focuses on differences between the low-and high-PGE c...Extremely abundant PGE-minerals(PGM)hosted in chromitites from the Veria ophiolite complex in Macedonia(N.Greece)may be unique among ophiolite complexes.This study focuses on differences between the low-and high-PGE chromitites.New textural,mineralogical and geochemical constraints from those ores are presented,aiming to define factors controlling the PGE enrichment in a supra subduction environment,in the light of postmagmatic processes.The whole ore analyses for mmajor and trace elements indicated an unusually high-IPGE content(up to 25 ppm)and higher Fe,Ca,Mn,Zn and V contents in high-PGE compared to low-PGE in massive chromitites.The wide compositional variation of chromite,even in the same polished section,the occurrence of very fine PGM(less than 20μm)as inclusions within chromite and extremely large(>1000μm),angular or fine-grained PGM aggregates ones within a matrix of highly fragmented chromite-Cr-garnet matrix,may indicate crystallization/recrystallization of chromite from more than one precursor phases.Laurite(RuS2)is very limited,occurring as remnants surrounding by Ru–Os–Ir oxides/hydroxides,of a wide compositional variation.Irarsite occurs as euhedral crystals up to 200μm,surrounding by chromite,as anhedral exsolutions 1–200μm within laurite,or creating segregates with platarsite and relics of(Ru,Pt,Rh,Os)sulfarsenides.Platinum–Ru–Rh–Pd-minerals occur commonly as relatively fine-grained assemblages,up to 50μm,along with irarsite and other relics of(Ru,Pt,Rh,Os)sulfarsenides.Pt-alloys show a variation ranging from tetraferroplatinum to Pt–Ir–Fe–Ni alloys.The presence of laurite relics in large IPGM,awaruite,heazlewoodite,and carbon-bearing material reflecting a super-reducing environment,and the transformation of primary PGM into Os–Ir–Ru-alloys and oxides/hydroxides in association with Fe-chromite and Fe3t-bearing garnet(andradite-uvarovite solidsolution series)may reflect changes of the redox conditions from reducing to oxidizing.The relatively high Na content in hydrous mineral inclusions within high-PGE chromitites suggest a hydrous mantle source and provide the possibility for estimation of the P(average 3.0 kbar)and T(average 874C),indicating formation at a shallow mantle environment.展开更多
The Indian shield comprises a number of Archean–Paleoproterozoic cratonic blocks and predominantly Meso–Neoproterozoic mobile belts with Archean protoliths.All these ancient cratons were thought to be integral parts of
The Scandinavian Caledonides comprise nappe stacks of far-travelled allochthons that record closure of the Iapetus Ocean and subsequent continental collision of Baltica and Laurentia.The Seve Nappe Complex(SNC)of the ...The Scandinavian Caledonides comprise nappe stacks of far-travelled allochthons that record closure of the Iapetus Ocean and subsequent continental collision of Baltica and Laurentia.The Seve Nappe Complex(SNC)of the Scandinavian Caledonides includes relics of the outermost Baltoscandian passive margin that were subducted to mantle depths.The earliest of the deep subduction events has been dated to ca.500-480 Ma.Evidence of this event has been reported from the northern exposures of the SNC.Farther south in the central and southern segments of the SNC,(ultra)high-pressure rocks have yielded younger ages in the range of ca.470-440 Ma.This study provides the first record of the early Caledonian event in the southern SNC.The evidence has been obtained by depth profiling of zircon grains that were extracted from the Tv?r?klumparna microdiamond-bearing gneiss.These zircon grains preserve eclogite facies overgrowths that crystallized at 482.6±3.8 Ma.A second,chemically-distinct zircon overgrowth records granulite facies metamorphism at 439.3±3.6 Ma,which corroborates previous geochronological evidence for granulite facies metamorphism at this time.Based on these results,we propose that the entire outer margin of Baltica was subducted in the late Cambrian to early Ordovician,but the record of this event may be almost entirely eradicated in the vast majority of lithologies by pervasive late Ordovician to early Silurian metamorphism.展开更多
In response to the proposal by the Earth Science community of China,we are delighted to organize this special issue of Geoscience Frontiers(GSF)in honor of the work by Xuanxue Mo,Professor of Petrology and Geochemistr...In response to the proposal by the Earth Science community of China,we are delighted to organize this special issue of Geoscience Frontiers(GSF)in honor of the work by Xuanxue Mo,Professor of Petrology and Geochemistry of China University of Geosciences(Beijing)and Academician of the Chinese Academy of Sciences,as a tribute to him on his 80th birthday.In his over 50 years of professional career,Prof.Mo has contributed enormously to the developments of China’s Earth Sciences and it is fair to say that Prof.Mo is one of the most influential administrators,educators and researchers in China’s Earth Science community and also internationally.The research papers assembled in this special issue reflect the authors’appreciation of Prof.Mo who has benefitted them as students,collaborators and colleagues over the years.展开更多
The Singhbhum craton of the eastern India consists of the Singhbhum Granite Complex(SGC)and the Chotanagpur Gneissic Complex(CGC)separated by the Singhbhum Mobile Belt(SMB).The CGC is intruded by Mesoproterozoic as we...The Singhbhum craton of the eastern India consists of the Singhbhum Granite Complex(SGC)and the Chotanagpur Gneissic Complex(CGC)separated by the Singhbhum Mobile Belt(SMB).The CGC is intruded by Mesoproterozoic as well as Cretaceous mafic dykes;in展开更多
Tectonic evolution and paleogeography of the two major continental blocks Fennoscandia and VolgoSarmatia during their docking to form the East European Craton(Baltica)at 1.8–1.7 Ga represent important‘puzzle
The Fushe Kuqe costal aquifer is a typical confined alluvial aquifer.The aquifer medium consists of sand-gravel and silt-clay layers intercalation which gave it a multilayer character.The aquifer recharge occurs mainl...The Fushe Kuqe costal aquifer is a typical confined alluvial aquifer.The aquifer medium consists of sand-gravel and silt-clay layers intercalation which gave it a multilayer character.The aquifer recharge occurs mainly by water infiltration from the Rver Mat in the North,and from River Droja in the South.The water flow direction is from northeast to southwest and from southeast to northwest,discharging to the Adriatic Sea.Based on the chloride and TDS(Total Solids Dissolved)content in groundwater,an advancement of sea water intrusion into aquifer was evidenced.The direction of sea water wedge is from coastal south-western sectors towards the north-eastern ones.Sample No.6,8,9 and 10 show chloride concentrations over 100 mg/L and Na/Cl ratios less than 0.86 implying that the groundwater is impacted by sea water intrusion.SR(Simpson Ratio)values of 1.15 and 1.09 for water sample No.8 and 10 are indications of a slight seawater influence,while groundwater of sample no.6 and 9 have SR values of 6.02 and 12.35 which are typical for a highly contamination by sea water.All the points of sampled groundwater fall above the GMWL,indicating that they have suffered a preliminary evaporation before entering the aquifer,likely in the hydropower lakes of Ulza and Shkopet upstream the River Mat course.Despite the narrow range ofδ18O andδ2H values(-6.80‰to-8.00‰and-54.00‰to 42.00‰,respectively),the points of sample No.6,8,9,10 fall on the fresh water-seawater mixing line,indicating the influence of the seawater intrusion.展开更多
In the Benja of Permeti village, eight springs are located in the Lengarica creek, and their curative values are known and used since the time of the Roman Empire. The eight springs erupt mineral water with temperatur...In the Benja of Permeti village, eight springs are located in the Lengarica creek, and their curative values are known and used since the time of the Roman Empire. The eight springs erupt mineral water with temperatures in the range of 23-30℃ and yields in the range of 8 up to more than 40 L/s. The geothermal fluid, even though with relatively low temperatures, represent a competitive energy resource. The geothermal water flows directly to the river of Langarica, similarly with the other geothermal resources of Albania can be "translated" as "throwing in the creek" of considerable monetary values, delay in the economic development, infrastructure and also negative social impacts in the region. This paper aims to show that these waters are a competitive energy resource by the implementation of a combined and cascade system, and also they can by efficiently used for greenhouses, aquaculture and salts extraction.展开更多
基金jointly funded by the National Natural Science Foundation of China(Grant Nos.41972120,42172129)the State Key Laboratory of Paleobiology and Stratigraphy(Nanjing Institute of Geology and Paleontology,CAS)(Grant No.173131)+1 种基金the Science and Technology Cooperation Project of the CNPC-SWPU Innovation Alliance(Grant No.2020CX050103)the China Postdoctoral Science Foundation(Grant No.2021M702720)。
文摘Deep-water gravity depositional processes and evolution in arc systems have become topics of intense research focus in recent years.This study discusses the co-evolution of volcanism and deep-water gravity flow deposits at the southern margin of the Junggar Basin,based on petrology,geochronology and geochemical analyses.The results show that a massive collapse of unstable sediments from the slope was triggered by volcanism,resulting in the formation of slumping gravity flows.The occurrence of volcanic beds in the slump deposits confirm that synchronous volcanism likely affected sediment instability,triggering gravity flows.The Th/Yb,Ta/Yb and Th/Ta elemental ratios,U-Pb ages of detrital zircons and paleocurrent directions indicate that the North Tianshan(NTS)island arc represents the provenance of the Qianxia Formation.Moreover,statistical data on the pyroclastic components in the gravity flow deposits reveal an intensity index of volcanism,indicating that volcanism is strongly related to gravity flow deposits,especially in terms of the type and distribution of the deposits.A model for volcanically-triggered deep-water gravity flow deposits is established,in order to provide a more in-depth understanding of the co-evolution of volcanism and gravity flow deposits within the depositional setting of the late Paleozoic NTS oceanic subduction margin in the Junggar Basin.
文摘The development of technology and the demands of groups of interest for standardized digital geospatial information are increasing daily.The necessity for referred geospatial information,according to a Referencing Coordinating System and European Standards,through a national GIS(Geographic Information System)system,requires a decision making of national and institutional importance.ASIG(State Authority for Geospatial Information)is the institution that administrates,implements,and maintains the NSDI(National Spatial Data Infrastructure).It is calculated that 80%of decision-making by public or private institutions uses geospatial data with a well-organized structure that enables efficiency.Thus,standardization of geospatial data by topic is one of the main objectives of implementing the NSDI in Albania.This is a complex task for the standard and the harmonization of geospatial data,which can be a good opportunity for professional awareness.This study shows in detail the methodology for the creation and implementation of data specification for geospatial information in Albania on the theme:Geology,adoption of the technical specification of the INSPIRE directive as well as the importance of ASIG as an institution that builds and maintains NSDI in Albania.
文摘Venusian coronae are large(60-2600 km diameter)tectono-magmatic features characterized by quasi-circular graben-fissure systems and topographic features such as a central dome,central depression,circular rim or circular
基金The study was partially financed by AGH-UST 16.16.140.315/10.
文摘Groundwater samples were evaluated throughout Turkana County(Kenya,East Africa)while looking for drinking water sources.Some samples showed high concentrations of fluoride with values in the range of 0.15–5.87 mg/L.Almost 50%of the samples exceeded the WHO and Kenyan potable water standard guideline value of 1.5 mg/L for drinking water quality.The hydrogeochemical studies revealed that the dominant cation in water is Na^(+)and the dominant anion is HCO_(3)^(-)resulting in Na-HCO_(3) type of groundwater,followed by Ca/Mg-HCO_(3) or Na-SO_(4) and Na-Cl in a few cases.Speciation modelling revealed that the groundwater is undersaturated with respect to gypsum and anhydrite,mostly undersaturated with respect to fluorite(6 samples are at equilibrium),and supersaturated or at equilibrium with respect to calcite(CaCO_(3)).Precipitation of calcite favours the dissolution of F-rich minerals in the alkaline medium.Simultaneously,groundwater is enriched with sodium and bicarbonate,probably as a result of chemical weathering of Na-feldspar.Investigated groundwater can be presumably used for drinking purposes from 17 wells,but a detailed investigation of other trace element concentrations is necessary.
文摘The article considers the issue of the world cities in terms of sustainable development.The population has been increasing in such intensive rates never reached during the middle of the 20th century.The expansion of the cities indicates,on the one hand,the growth of the world’s general socio-economic development,on the other hand,it raises a number of economic,social and environmental problems.The purpose of this paper is to analyze the current state and prospects of the world cities in terms of the sustainable development concept,to identify opportunities,threats,strengths and weaknesses of the world cities,to determine the role of cities in the con-temporary global world and consider further research of the world’s cities.The authors analyzed the world cities rankings and noted that highly developed cities have more chances to quickly implement the sustainable devel-opment concept compared to medium-sized cities due to larger financial resources.The authors built a SWOT analysis of the world cities transformation in terms of the sustainable development concept,identified strengths,weaknesses,opportunities and threats.According to the results of the SWOT analysis,the authors established that sustainable development of cities requires significant investments,particularly in the social sphere develop-ment,purification,and preservation of urban nature from the anthropogenic impacts.The research result is the systematization of the sustainable development criteria used in compiling the world cities rankings,determining the possibilities of the contemporary cities transition to the sustainable development concept.
基金Supported by the China National Science and Technology Major Project(2017ZX05063002-009)National Natural Science Foundation of China(4177021173,41972120)CNPC-Southwest Petroleum University Innovation Consortium Science and Technology Cooperation Project(2020CX020000)。
文摘Based on field outcrop data,the effects of cyclic change of astronomical orbit and volcanic activity on organic carbon accumulation during the Late Ordovician-Early Silurian in the Upper Yangtze area were studied using cyclostratigraphic and geochemical methods.d13 C and chemical index of alteration(CIA)were used to filter the astronomical orbit parameters recorded in sediments.It is found that the climate change driven by orbital cycle controls the fluctuations of sea level at different scales,obliquity forcing climate changes drive thermohaline circulation(THC)of the ocean,and THC-induced bottom currents transport nutrient-laden water from high latitude regions to the surface water of low-latitude area.Hence,THC is the main dynamic mechanism of organic-carbon supply.The marine productivity indexes of Ba/Al and Ni/Al indicate that volcanic activities had limited effect on marine productivity but had great influences on organic carbon preservation efficiency in late Hirnantian(E4).Paleo-ocean redox environmental indicators Th/U,V/Cr and V/(V+Ni)show that there is a significant correlation between volcanism and oxygen content in Paleo-ocean,so it is inferred that volcanisms controlled the organic carbon preservation efficiency by regulating oxygen content in Paleo-ocean,and the difference in volcanism intensity in different areas is an important factor for the differential preservation efficiency of organic carbon.The organic carbon input driven by orbital cycle and the preservation efficiency affected by volcanisms worked together to control the enrichment of organic carbon in the Middle–Upper Yangtze region.
文摘This paper aims to advance previous studies on the iron and manganese content in groundwater of Rrogozhina aquifer (western Albania) and to show the factors which control the content of both iron and manganese in groundwater of this aquifer. Rrogozhina aquifer represents an important groundwater source of the country whose relevance was highly increased during recent years because of the demographic expansion in this region. This is a typically multi-layered artesian aquifer which consists of sandstone and conglomerate with high heterogeneous permeability. The groundwater mostly belongs to HCO3-Mg-Ca hydrochemical type. The content of soluble iron and manganese in groundwater ranges from 0.004 mg/L to 0.7 mg/L, and from 0.0 mg/L to 1.147 mg/L, respectively. Deeper the groundwater occurs and longer the distance from the recharge zone, higher is the content of Fe2+ in groundwater due to gradual depletion of Oe in groundwater. The content of iron is higher than that WHO and EU recommended, which were 21% and 25% respectively, while the content of manganese were 17% and 23%, respectively. Abstraction of groundwater with high quantities by deeper wells would be accompanied by increase of dissolved iron and manganese content in groundwater which should be treated (with aeration) in order to decrease the content of these two elements in the water before using it.
基金grant IDEI-PN-II-ID-PCE-2011-30100 from the Romanian National Science Foundation(ANCS-CNCS)
文摘The basement of the Romanian Carpathians is made of Neoproterozoic to early Paleozoic peri- Gondwanan terranes variably involved in the Variscan orogeny, similarly to other basement terrains of Europe. They were hardly dismembered during the Alpine orogeny and traditionally have their own names in the three Carpathian areas. The Danubian domain of the South Carpathians comprises the Dragsan and Lainici-Paiius peri-Amazonian terranes. The Dragsan terrane originated within the ocean surrounding Rodinia and docked with Rodinia at -800 Ma. It does not contain Cadomian magmatism and consequently it is classified as an Avalonian extra-Cadomian terrane, The Lainici-Pfiius terrane is a Ganderian fragment strongly modified by Cadomian subduction-related magmatism, It is attached to the Moesia platform. The TisoviD terrane is an ophiolite that marks the boundary between Drfagsan and Lainici-Paius terranes. The other basement terranes of the Romanian Carpathians originated close to the Ordovician North- African orogen, as a result of the eastern Rheic Ocean opening and closure. Except for the Sebes-Lotru terrane that includes a lower metamorphic unit of Cadomian age, all the other terranes (Bretila, Tulghes, Negrisoara and Rebra in the East Carpathians, Somes, Biharia and Baia de Aries in the Apuseni mountains, Fagaras, Leaota, Carat and Pades in the South Carpathians) represent late Cambrian-Ordovician rock assemblages. Their provenance, is probably within paleo-nortbeast Africa, close to the Arabian-Nubian shield. The late Cambrian-Ordovician terranes are defined here as Carpathian-type terranes. According to their lithostratigraphy and origin, some are of continental margin magmatic arc setting, whereas others formed in rift and back-arc environment and closed to passive continental margin settings. In a paleo- geographic reconstruction, the continental margin magmatic arc terranes were first that drifted out, followed by the passive continental margin terranes with the back-arc terranes in their front. They accreted to Laurussia during the Variscan orogeny. Some of them (Sebes-Lotru in South Carpathians and Baia de Aries in Apuseni mountains) underwent eclogite-grade metamorphism. The Danubian terranes, the Bretila terrane and the Somes terrane were intruded by Variscan granitoids.
文摘The Sinuiju Formation in Paekto-dong,Sinuiju City in the Democratic People's Republic of Korea has yielded Mesozoic nonmarine bivalve fossils,which is the first occurrence of such in the DPRK.Based on these fossil specimens,a new Cretaceous bivalve assemblage,the Arguniella yanshanensis-Sphaerium anderssoni Assemblage is erected.This assemblage includes Arguniella yanshanensis,A.lingyuanensis and Sphaerium anderssoni and can be compared with the Jehol Biota.The age of the Sinuiju Formation is also clarified and on the basis of the bivalves and the presence of a Eosestheria–Ephemeropsis–Lycoptera(E–E–L)assemblage,the formation is not Upper Jurassic,but Lower Cretaceous in age.
文摘Note: Items in Episodes' Classic Paper series normally analyze a single paper of major importance in the history of geosciences. The present contribution examines the book in which Milankovich summed up his life work. One of the few Serbian scientists of worldwide renown, Milutin Milankovich, was professor of applied mathematics at Belgrade University. He was born in 1879 in Dalj, near Osjek (today in Croatia). He studied construction engineering in Vienna, graduated in 1902 and gained his PhD in 1904. After a brief but successful engineering practice in Vienna, he moved to Belgrade University. During his thirty years of work there he produced: a mathematical theory of the Earth's climate (1920); his astronomic theory of climatic changes (1930, 1938, 1938a); and his theory of the secular wandering of the Earth's poles (1933). He retired in 1955 and died in Belgrade in 1958.
基金funded by the Ministry of Science and Higher Education under project DS-AGH University of Science and Technology,WGGiOS-KGOiG No.11.11.140.173 (to M.Bak and to L.Natkaniec-Nowak),and DS-UP-WGB-4n (to K.Bak)
文摘An association of organic-walled microfossils consisting of filamentous cyanobacteria, algal coenobia and acanthomorphic acritarch have been documented from non-calcareous claystones and mudstones of the Pepper Mountains Shale Formation(PMSF), located in its stratotype area in the Pepper Mountains, which are part of the Holy Cross Mountains in Poland. These sediments represent the oldest strata of the ?ysogóry Unit, deposited on the edge of the East European Craton(Baltica). Non-branched, ribbon-like and thread-like cyanobacteria trichomes exhibit morphological similarities to families Nostocaceae and Oscillatoriaceae. Cells assembled in rounded to irregular clusters of monospecific agglomerations represent multicellular algal coenobia, attributed to the family Scenedesmaceae. The co-occurrence of acritarchs belonging to species as Eliasum llaniscum, Cristallinium ovillense and Estiastra minima indicates that the studied material corresponds to the lower Middle Cambrian. Deposition of the PMSF took place in shallow marine environment, influenced by periodical freshwater inputs. The varying degree of coloration of organic-walled microfossils is interpreted in this study as factor indication of possible different source of their derivation. Dark brown walls of cells assembled in algal coenobia might have sustained previous humification in humid, terrestrial environments, which preceded their river transport into the sea together with nutrients, causing occasional blooms of cyanobacteria in the coastal environment and the final deposition of both groups of organisms in marine deposits.
基金The National and Kapodistrian University of Athens(NKUA)is greatly acknowledged for the financial support(Grant No.KE_11078)of this work.
文摘Extremely abundant PGE-minerals(PGM)hosted in chromitites from the Veria ophiolite complex in Macedonia(N.Greece)may be unique among ophiolite complexes.This study focuses on differences between the low-and high-PGE chromitites.New textural,mineralogical and geochemical constraints from those ores are presented,aiming to define factors controlling the PGE enrichment in a supra subduction environment,in the light of postmagmatic processes.The whole ore analyses for mmajor and trace elements indicated an unusually high-IPGE content(up to 25 ppm)and higher Fe,Ca,Mn,Zn and V contents in high-PGE compared to low-PGE in massive chromitites.The wide compositional variation of chromite,even in the same polished section,the occurrence of very fine PGM(less than 20μm)as inclusions within chromite and extremely large(>1000μm),angular or fine-grained PGM aggregates ones within a matrix of highly fragmented chromite-Cr-garnet matrix,may indicate crystallization/recrystallization of chromite from more than one precursor phases.Laurite(RuS2)is very limited,occurring as remnants surrounding by Ru–Os–Ir oxides/hydroxides,of a wide compositional variation.Irarsite occurs as euhedral crystals up to 200μm,surrounding by chromite,as anhedral exsolutions 1–200μm within laurite,or creating segregates with platarsite and relics of(Ru,Pt,Rh,Os)sulfarsenides.Platinum–Ru–Rh–Pd-minerals occur commonly as relatively fine-grained assemblages,up to 50μm,along with irarsite and other relics of(Ru,Pt,Rh,Os)sulfarsenides.Pt-alloys show a variation ranging from tetraferroplatinum to Pt–Ir–Fe–Ni alloys.The presence of laurite relics in large IPGM,awaruite,heazlewoodite,and carbon-bearing material reflecting a super-reducing environment,and the transformation of primary PGM into Os–Ir–Ru-alloys and oxides/hydroxides in association with Fe-chromite and Fe3t-bearing garnet(andradite-uvarovite solidsolution series)may reflect changes of the redox conditions from reducing to oxidizing.The relatively high Na content in hydrous mineral inclusions within high-PGE chromitites suggest a hydrous mantle source and provide the possibility for estimation of the P(average 3.0 kbar)and T(average 874C),indicating formation at a shallow mantle environment.
文摘The Indian shield comprises a number of Archean–Paleoproterozoic cratonic blocks and predominantly Meso–Neoproterozoic mobile belts with Archean protoliths.All these ancient cratons were thought to be integral parts of
基金funded by the National Science Centre,Poland CALSUB project no.2014/14/E/ST10/00321financial support has been provided by the Polish National Agency for Academic Exchange Scholarship PPN/IWA/2018/1/00030/U/00001 granted to C.Barnes。
文摘The Scandinavian Caledonides comprise nappe stacks of far-travelled allochthons that record closure of the Iapetus Ocean and subsequent continental collision of Baltica and Laurentia.The Seve Nappe Complex(SNC)of the Scandinavian Caledonides includes relics of the outermost Baltoscandian passive margin that were subducted to mantle depths.The earliest of the deep subduction events has been dated to ca.500-480 Ma.Evidence of this event has been reported from the northern exposures of the SNC.Farther south in the central and southern segments of the SNC,(ultra)high-pressure rocks have yielded younger ages in the range of ca.470-440 Ma.This study provides the first record of the early Caledonian event in the southern SNC.The evidence has been obtained by depth profiling of zircon grains that were extracted from the Tv?r?klumparna microdiamond-bearing gneiss.These zircon grains preserve eclogite facies overgrowths that crystallized at 482.6±3.8 Ma.A second,chemically-distinct zircon overgrowth records granulite facies metamorphism at 439.3±3.6 Ma,which corroborates previous geochronological evidence for granulite facies metamorphism at this time.Based on these results,we propose that the entire outer margin of Baltica was subducted in the late Cambrian to early Ordovician,but the record of this event may be almost entirely eradicated in the vast majority of lithologies by pervasive late Ordovician to early Silurian metamorphism.
文摘In response to the proposal by the Earth Science community of China,we are delighted to organize this special issue of Geoscience Frontiers(GSF)in honor of the work by Xuanxue Mo,Professor of Petrology and Geochemistry of China University of Geosciences(Beijing)and Academician of the Chinese Academy of Sciences,as a tribute to him on his 80th birthday.In his over 50 years of professional career,Prof.Mo has contributed enormously to the developments of China’s Earth Sciences and it is fair to say that Prof.Mo is one of the most influential administrators,educators and researchers in China’s Earth Science community and also internationally.The research papers assembled in this special issue reflect the authors’appreciation of Prof.Mo who has benefitted them as students,collaborators and colleagues over the years.
文摘The Singhbhum craton of the eastern India consists of the Singhbhum Granite Complex(SGC)and the Chotanagpur Gneissic Complex(CGC)separated by the Singhbhum Mobile Belt(SMB).The CGC is intruded by Mesoproterozoic as well as Cretaceous mafic dykes;in
基金funded by grant 14-05-00731 from the Russian Foundation of Basic Research
文摘Tectonic evolution and paleogeography of the two major continental blocks Fennoscandia and VolgoSarmatia during their docking to form the East European Craton(Baltica)at 1.8–1.7 Ga represent important‘puzzle
文摘The Fushe Kuqe costal aquifer is a typical confined alluvial aquifer.The aquifer medium consists of sand-gravel and silt-clay layers intercalation which gave it a multilayer character.The aquifer recharge occurs mainly by water infiltration from the Rver Mat in the North,and from River Droja in the South.The water flow direction is from northeast to southwest and from southeast to northwest,discharging to the Adriatic Sea.Based on the chloride and TDS(Total Solids Dissolved)content in groundwater,an advancement of sea water intrusion into aquifer was evidenced.The direction of sea water wedge is from coastal south-western sectors towards the north-eastern ones.Sample No.6,8,9 and 10 show chloride concentrations over 100 mg/L and Na/Cl ratios less than 0.86 implying that the groundwater is impacted by sea water intrusion.SR(Simpson Ratio)values of 1.15 and 1.09 for water sample No.8 and 10 are indications of a slight seawater influence,while groundwater of sample no.6 and 9 have SR values of 6.02 and 12.35 which are typical for a highly contamination by sea water.All the points of sampled groundwater fall above the GMWL,indicating that they have suffered a preliminary evaporation before entering the aquifer,likely in the hydropower lakes of Ulza and Shkopet upstream the River Mat course.Despite the narrow range ofδ18O andδ2H values(-6.80‰to-8.00‰and-54.00‰to 42.00‰,respectively),the points of sample No.6,8,9,10 fall on the fresh water-seawater mixing line,indicating the influence of the seawater intrusion.
文摘In the Benja of Permeti village, eight springs are located in the Lengarica creek, and their curative values are known and used since the time of the Roman Empire. The eight springs erupt mineral water with temperatures in the range of 23-30℃ and yields in the range of 8 up to more than 40 L/s. The geothermal fluid, even though with relatively low temperatures, represent a competitive energy resource. The geothermal water flows directly to the river of Langarica, similarly with the other geothermal resources of Albania can be "translated" as "throwing in the creek" of considerable monetary values, delay in the economic development, infrastructure and also negative social impacts in the region. This paper aims to show that these waters are a competitive energy resource by the implementation of a combined and cascade system, and also they can by efficiently used for greenhouses, aquaculture and salts extraction.