Kongsfjorden is a fjord in Spitsbergen（Svalbard archipelago）that lies adjacent to both Arctic and Atlantic water masses and is therefore a suitable site to understand the effects of climate change on ecosystems.To d...Kongsfjorden is a fjord in Spitsbergen（Svalbard archipelago）that lies adjacent to both Arctic and Atlantic water masses and is therefore a suitable site to understand the effects of climate change on ecosystems.To decipher the effect of the lateral advection of transformed Atlantic water （TAW）within the fjord,spatial variations of foraminiferal tests,their test size variations and stable isotopic composition（δ^（13）C andδ^（18）O）in the surface sediments were studied.Total organic carbon and textural analyses were also carried out.The dominant benthic foraminifera included Nonionellina labradorica,Elphidium excavatum,Cassidulina reniforme,Quinqueloculina stalkeri and Islandiella islandica.Nonionellina labradorica was the predominant species in the outer fjord,whereas Elphidium excavatum and Cassidulina reniforme were dominant in the inner fjord.Total organic carbon and the test size of Nonionellina labradorica within the fjord were highly correlated（r=0.97）and both showed a decreasing trend towards the inner fjord.Based on the distribution and abundance of Nonionellina labradorica as well as temperature profiles,we suggest that there was little or no major change in the lateral advection of TAW within the fjord in the immediate past.展开更多
Cryoconite samples were collected from two different climatic domains i.e.,the Sutri Dhaka glacier,western Himalaya India and Svalbard glaciers,the Spitsbergen,Arctic,to understand the elemental source and elemental d...Cryoconite samples were collected from two different climatic domains i.e.,the Sutri Dhaka glacier,western Himalaya India and Svalbard glaciers,the Spitsbergen,Arctic,to understand the elemental source and elemental deposition patterns.The data of geochemical analysis suggest that the Himalayan cryoconite samples accumulate higher concentrations as compared to the cryoconite samples of the Arctic glaciers.The concentration of lithophile elements(Cs,Li,Rb and U)was recorded higher in the cryoconite holes of the Himalayas,especially,in the lower to the higher parts of the glacier,whereas,lower concentrations were recorded in the Arctic samples.Chalcophile elements in the Himalayan cryoconites are enriched in As and Bi while the Arctic cryoconite samples show a higher concentration of Bi,Pb and As.The higher concentrations are responsible for influencing the ecosystem and in human health related issues.Siderophile elements(Co,Fe,Mn and Ni)show high concentrations in the Himalayan samples,whereas,the Arctic samples show minor variations and low elemental concentration in these elements,respectively.In addition,a few elements,such as Ag,Mg,and Ca show higher concentration in the Himalayan glacier samples.Ca also occurs in high concentrations in Arctic glacier samples.R-mode factor analysis of the Himalayas(Arctic)samples indicate that the elements are distributed in four(three)factors,explaining 89%(90%)of the variance in their elemental distribution.The Factor 1 suggests statistically significant positive loadings for most of the lithophile,chalcophile and siderophile elements of the "Himalayan" and the Arctic cryoconite samples.The sample-wise factor score distribution shows a considerable variation in the sampling locations along the glaciers of both the regions.Factors 2 and 3,demonstrate insignificant loading for most of the elements,except statistically significant positive loading in some of the elements of the both,Himalayan and Arctic "cryoconites".The higher elemental concentration in the cryoconites of the Himalayan region may be an indicator of the natural processes and/or attributed to the rapid industrialization in the Asian countries.展开更多
Lattice preferred orientation （LPO） and seismic anisotropy of orthopyroxene （enstatite） in mantle xenoliths from Spitsbergen, Svalbard, near the Arctic, are studied. LPOs of enstatite were determined using electro...Lattice preferred orientation （LPO） and seismic anisotropy of orthopyroxene （enstatite） in mantle xenoliths from Spitsbergen, Svalbard, near the Arctic, are studied. LPOs of enstatite were determined using electron backseattered diffraction （EBSD）. We found four types of LPOs of orthopyroxene and defined them as type-AC, -AB, -BC, and -ABC. Type-AC LPO of orthopyroxene is defined as （100） plane aligned subparallel to foliation and [001] axis aligned subparallel to lineation. Type-AB LPO is defined as （100） plane aligned subparallel to foliation and [010] axis aligned subparallel to linea- tion. Type-BC LPO is defined as （010） plane aligned subparallel to foliation and [001] axis aligned subparallel to lineation. Type-ABC LPO is defined as both （100） and （010） planes aligned subparallel to foliation with a girdle distribution of both [100] and [010] axes normal to lineation and [001] axis aligned subparallel to lineation. We report for the first time the type-AB, -BC, and -ABC LPO of orthopyroxerie. We found that the LPO pattern has a correlation with the content of orthopyroxene in the specimen. Nicolet 6700 FTIR （Fourier transformation infrared） study of enstatite showed that type-AC LPO was observed mostly in the samples of enstatite with low water content. It is found that the strength of the LPO of enstatite decreases with increasing water content and has a correlation with the strength of the LPO of olivine： the stronger the LPO of enstatite, the stronger the LPO of olivine. Seismic anisotropy of enstatite was smaller than that of olivine in the same specimen.展开更多
The experimental study of the seepage processes’sources formation in structures of the Arctic Region was carried out using modified methods of frequency-resonance(FR)processing and decoding of satellite images and ph...The experimental study of the seepage processes’sources formation in structures of the Arctic Region was carried out using modified methods of frequency-resonance(FR)processing and decoding of satellite images and photographs with the vertical scanning of the cross-sections.The newly obtained results show that the intensity and dynamics of the methane seeps and pockmarks fields’formation depend on active deep degassing processes in the continental margin structures.The use of direct FR-sounding technologies allows for determining the probable origin and depth of geological sources of gas migration at marginal migration centers in Greenland,and Norwegian and Barents Seas.New results confirm the crust-mantle gas fluids’influence on the nature and degassing processes features in the scan points of polar marginal structures.These data are important arguments in favor of the“volcanic model”of various structural elements formation in this and other regions.The FR technologies data also showed a possibility of seeps use as shallow and deep hydrocarbon field indicators in gas emission areas.These independent data can be used in compiling models of the deep lithosphere structure and possible mechanisms of abiogenetic hydrocarbon formation in Arctic margin structures.The authors suppose that hydrocarbons through deep channels migrate(from 57 km deep)to the upper crustal horizons where their fields can form.During this migration,gas seeps and pockmarks are formed on the sea bottom and part of the gas can migrate into the atmosphere.Data show that basaltic volcanoes in Greenland scan points can be the real channels through which hydrogen migrates to the upper crustal horizons and further into the atmosphere.Active gas migration in Arctic seepage areas can be an important factor in the global climate change processes.展开更多
文摘Kongsfjorden is a fjord in Spitsbergen（Svalbard archipelago）that lies adjacent to both Arctic and Atlantic water masses and is therefore a suitable site to understand the effects of climate change on ecosystems.To decipher the effect of the lateral advection of transformed Atlantic water （TAW）within the fjord,spatial variations of foraminiferal tests,their test size variations and stable isotopic composition（δ^（13）C andδ^（18）O）in the surface sediments were studied.Total organic carbon and textural analyses were also carried out.The dominant benthic foraminifera included Nonionellina labradorica,Elphidium excavatum,Cassidulina reniforme,Quinqueloculina stalkeri and Islandiella islandica.Nonionellina labradorica was the predominant species in the outer fjord,whereas Elphidium excavatum and Cassidulina reniforme were dominant in the inner fjord.Total organic carbon and the test size of Nonionellina labradorica within the fjord were highly correlated（r=0.97）and both showed a decreasing trend towards the inner fjord.Based on the distribution and abundance of Nonionellina labradorica as well as temperature profiles,we suggest that there was little or no major change in the lateral advection of TAW within the fjord in the immediate past.
基金Ministry of Earth Science,New Delhi and Indian Council of Agriculture Research for their financial support
文摘Cryoconite samples were collected from two different climatic domains i.e.,the Sutri Dhaka glacier,western Himalaya India and Svalbard glaciers,the Spitsbergen,Arctic,to understand the elemental source and elemental deposition patterns.The data of geochemical analysis suggest that the Himalayan cryoconite samples accumulate higher concentrations as compared to the cryoconite samples of the Arctic glaciers.The concentration of lithophile elements(Cs,Li,Rb and U)was recorded higher in the cryoconite holes of the Himalayas,especially,in the lower to the higher parts of the glacier,whereas,lower concentrations were recorded in the Arctic samples.Chalcophile elements in the Himalayan cryoconites are enriched in As and Bi while the Arctic cryoconite samples show a higher concentration of Bi,Pb and As.The higher concentrations are responsible for influencing the ecosystem and in human health related issues.Siderophile elements(Co,Fe,Mn and Ni)show high concentrations in the Himalayan samples,whereas,the Arctic samples show minor variations and low elemental concentration in these elements,respectively.In addition,a few elements,such as Ag,Mg,and Ca show higher concentration in the Himalayan glacier samples.Ca also occurs in high concentrations in Arctic glacier samples.R-mode factor analysis of the Himalayas(Arctic)samples indicate that the elements are distributed in four(three)factors,explaining 89%(90%)of the variance in their elemental distribution.The Factor 1 suggests statistically significant positive loadings for most of the lithophile,chalcophile and siderophile elements of the "Himalayan" and the Arctic cryoconite samples.The sample-wise factor score distribution shows a considerable variation in the sampling locations along the glaciers of both the regions.Factors 2 and 3,demonstrate insignificant loading for most of the elements,except statistically significant positive loading in some of the elements of the both,Himalayan and Arctic "cryoconites".The higher elemental concentration in the cryoconites of the Himalayan region may be an indicator of the natural processes and/or attributed to the rapid industrialization in the Asian countries.
基金supported by the Korea Meteorological Ad-ministration Research and Development Program (No. CATER 2008-5112)
文摘Lattice preferred orientation （LPO） and seismic anisotropy of orthopyroxene （enstatite） in mantle xenoliths from Spitsbergen, Svalbard, near the Arctic, are studied. LPOs of enstatite were determined using electron backseattered diffraction （EBSD）. We found four types of LPOs of orthopyroxene and defined them as type-AC, -AB, -BC, and -ABC. Type-AC LPO of orthopyroxene is defined as （100） plane aligned subparallel to foliation and [001] axis aligned subparallel to lineation. Type-AB LPO is defined as （100） plane aligned subparallel to foliation and [010] axis aligned subparallel to linea- tion. Type-BC LPO is defined as （010） plane aligned subparallel to foliation and [001] axis aligned subparallel to lineation. Type-ABC LPO is defined as both （100） and （010） planes aligned subparallel to foliation with a girdle distribution of both [100] and [010] axes normal to lineation and [001] axis aligned subparallel to lineation. We report for the first time the type-AB, -BC, and -ABC LPO of orthopyroxerie. We found that the LPO pattern has a correlation with the content of orthopyroxene in the specimen. Nicolet 6700 FTIR （Fourier transformation infrared） study of enstatite showed that type-AC LPO was observed mostly in the samples of enstatite with low water content. It is found that the strength of the LPO of enstatite decreases with increasing water content and has a correlation with the strength of the LPO of olivine： the stronger the LPO of enstatite, the stronger the LPO of olivine. Seismic anisotropy of enstatite was smaller than that of olivine in the same specimen.
文摘The experimental study of the seepage processes’sources formation in structures of the Arctic Region was carried out using modified methods of frequency-resonance(FR)processing and decoding of satellite images and photographs with the vertical scanning of the cross-sections.The newly obtained results show that the intensity and dynamics of the methane seeps and pockmarks fields’formation depend on active deep degassing processes in the continental margin structures.The use of direct FR-sounding technologies allows for determining the probable origin and depth of geological sources of gas migration at marginal migration centers in Greenland,and Norwegian and Barents Seas.New results confirm the crust-mantle gas fluids’influence on the nature and degassing processes features in the scan points of polar marginal structures.These data are important arguments in favor of the“volcanic model”of various structural elements formation in this and other regions.The FR technologies data also showed a possibility of seeps use as shallow and deep hydrocarbon field indicators in gas emission areas.These independent data can be used in compiling models of the deep lithosphere structure and possible mechanisms of abiogenetic hydrocarbon formation in Arctic margin structures.The authors suppose that hydrocarbons through deep channels migrate(from 57 km deep)to the upper crustal horizons where their fields can form.During this migration,gas seeps and pockmarks are formed on the sea bottom and part of the gas can migrate into the atmosphere.Data show that basaltic volcanoes in Greenland scan points can be the real channels through which hydrogen migrates to the upper crustal horizons and further into the atmosphere.Active gas migration in Arctic seepage areas can be an important factor in the global climate change processes.
