The prospects for expanding the mineral resource base in many countries are linked with the exploration of stranded sites localized at unexplored areas with complex natural and landscape conditions that make any groun...The prospects for expanding the mineral resource base in many countries are linked with the exploration of stranded sites localized at unexplored areas with complex natural and landscape conditions that make any ground survey,including magnetic prospecting,difficult and expensive.The current level of geology requires high-precision and large-scale data at the first stages of geological exploration.Since 2012,technologies of aeromagnetic surveying with unmanned aircraft vehicles(UAV)enter the market,but most of them are based on big fixed-wing UAV and do not allow to substantially increase the level of survey granularity compared with traditional aerial methods.To increase the scale of survey,it is necessary to reduce the altitude and speed of flight,for which the authors develop the methodical and technical solutions described in this article.To obtain data at altitudes of 5 m above the terrain even in a rugged relief,we created heavy multirotor UAVs that are stable in flight and may be used in a wide range of environmental conditions(even a moderate snowfall),and develop a special software to generate flight missions on the basis of digital elevation models.A UAV has special design to reduce magnetic interference of the flight platform;the magnetic sensor is hung below the aircraft.This technology was conducted in a considerable amount of magnetic surveys in the mountainous regions of East Siberia between 2014 and 2016.The results of the comparison between airborne and ground surveys are presented,which show that the sensitivity of the developed system in conjunction with low-altitude measurements can cover any geologically significant anomalies of the magnetic field.An unmanned survey is cheaper and more productive;the multirotor-based technologies may largely replace traditional ground magnetic exploration in scales of 1:10,000−1:1000.展开更多
Sulfur mass-independent fractionation(S-MIF)preserved in Archean sedimentary pyrite is interpreted to reflect atmospheric chemistry.Small ranges in Δ^(33)S that expanded into larger fractionations leading up to the G...Sulfur mass-independent fractionation(S-MIF)preserved in Archean sedimentary pyrite is interpreted to reflect atmospheric chemistry.Small ranges in Δ^(33)S that expanded into larger fractionations leading up to the Great Oxygenation Event(GOE;2.45–2.2 Ga)are disproportionately represented by sequences from the Kaapvaal and Pilbara Cratons.These patterns of S-MIF attenuation and enhancement may differ from the timing and magnitude of minor sulfur isotope fractionations reported from other cratons,thus obscuring local for global sulfur cycling dynamics.By expanding the Δ^(33)S record to include the relatively underrepresented São Francisco Craton in Brazil,we suggest that marine biogeochemistry affected S-MIF preservation prior to the GOE.In an early Neoarchean sequence(2763–2730 Ma)from the Rio das Velhas Greenstone Belt,we propose that low δ^(13)Corg(<-30‰)and dampened Δ^(33)S(-0.4‰to-0.7‰)in banded iron formation reflect the marine diagenetic process of anaerobic methane oxidation.The overlying black shale(TOC up to 7.8%)with higher δ^(13)Corg(-33.4‰to-19.2‰)and expanded Δ^(33)S(2.3‰±0.8‰),recorded oxidative sulfur cycling that resulted in enhance preservation of S-MIF input from atmospheric sources of elemental sulfur.The sequence culminates in a metasandstone,where concomitant changes to more uniform δCorg(-30‰to--25‰),potentially associated with the RuBisCO I enzyme,and near-zero Δ^(33)S(-0.04‰to 0.38‰)is mainly interpreted as evidence for local oxygen production.When placed in the context of other sequences worldwide,the Rio das Velhas helps differentiate the influences of global atmospheric chemistry and local marine diagenesis in Archean biogeochemical processes.Our data suggest that prokaryotic sulfur,iron,and methane cycles might have an underestimated role in pre-GOE sulfur minor isotope records.展开更多
Natural disasters such as volcanic eruptions,earthquakes,tsunamis,floods,fires,droughts,landslides and others occur frequently in most parts of our world.Therefore,many activities are being carried out to improve espe...Natural disasters such as volcanic eruptions,earthquakes,tsunamis,floods,fires,droughts,landslides and others occur frequently in most parts of our world.Therefore,many activities are being carried out to improve especially the Early Warning(EW)for disasters,but also all other phases of Disaster Management(DM)such as preparedness,awareness,response,recovery and mitigation.展开更多
This special issue is part of a double special issue(Part A was published in the previous issue of this journal)dealing with the role of Geographic Information(GI)for Early Warning(EW)and Disaster Management(DM).In th...This special issue is part of a double special issue(Part A was published in the previous issue of this journal)dealing with the role of Geographic Information(GI)for Early Warning(EW)and Disaster Management(DM).In the editorial of Part A we gave an introduction to the topic focussing on initiatives from the EU and China and we have highlighted the importance of Digital Earth for EWand DM.We have also reflected on the outcome of some events organized by the vip editors which were important for the topic and for this special issue.展开更多
Among the environmental threats,the intensification of natural hazards,such as soil erosion may threaten the integrity and value of cultural heritage sites.In this framework,the present study’s main objective was to ...Among the environmental threats,the intensification of natural hazards,such as soil erosion may threaten the integrity and value of cultural heritage sites.In this framework,the present study’s main objective was to identify archaeological sites susceptible by soil erosion,taking the case study of Chania prefecture in Crete Island.Remotely sensed and other available geospatial datasets were analyzed in a GIS-based empirical model,namely Unit Stream Power Erosion and Deposition(USPED),to estimate the average annual soil loss and deposition rates due to waterinduced erosion in the study area.The resultant erosion map was then intersected with the locations and surrounding zones of the known archaeological sites for identifying the sites and the portions of their vicinity being at risk.The results revealed that Chania prefecture and its cultural heritage are significantly affected by both soil loss and deposition processes.Between the two processes,soil loss was found to be more intensive,influencing a larger part of the prefecture(especially to the west)as well as a higher amount of archaeological sites.The extreme and high soil loss classes were also detected to cover the most considerable portion of the sites’surrounding area.The identification of the archaeological sites being most exposed to soil erosion hazard can constitute a basis for cultural heritage managers in order to take preventive preserva-tion measures and develop specific risk mitigation strategies.展开更多
基金This work was supported by the Council on grants of the President of the Russian Federation[Grant Number MK-3608.2018.5].
文摘The prospects for expanding the mineral resource base in many countries are linked with the exploration of stranded sites localized at unexplored areas with complex natural and landscape conditions that make any ground survey,including magnetic prospecting,difficult and expensive.The current level of geology requires high-precision and large-scale data at the first stages of geological exploration.Since 2012,technologies of aeromagnetic surveying with unmanned aircraft vehicles(UAV)enter the market,but most of them are based on big fixed-wing UAV and do not allow to substantially increase the level of survey granularity compared with traditional aerial methods.To increase the scale of survey,it is necessary to reduce the altitude and speed of flight,for which the authors develop the methodical and technical solutions described in this article.To obtain data at altitudes of 5 m above the terrain even in a rugged relief,we created heavy multirotor UAVs that are stable in flight and may be used in a wide range of environmental conditions(even a moderate snowfall),and develop a special software to generate flight missions on the basis of digital elevation models.A UAV has special design to reduce magnetic interference of the flight platform;the magnetic sensor is hung below the aircraft.This technology was conducted in a considerable amount of magnetic surveys in the mountainous regions of East Siberia between 2014 and 2016.The results of the comparison between airborne and ground surveys are presented,which show that the sensitivity of the developed system in conjunction with low-altitude measurements can cover any geologically significant anomalies of the magnetic field.An unmanned survey is cheaper and more productive;the multirotor-based technologies may largely replace traditional ground magnetic exploration in scales of 1:10,000−1:1000.
基金São Paulo Research Foundation(FAPESP grants2016/02933-2 to ABS,12/15824-6 to EPO and 2015/16235-2 to PP)the Agouron Institute(to WPG)for financial support。
文摘Sulfur mass-independent fractionation(S-MIF)preserved in Archean sedimentary pyrite is interpreted to reflect atmospheric chemistry.Small ranges in Δ^(33)S that expanded into larger fractionations leading up to the Great Oxygenation Event(GOE;2.45–2.2 Ga)are disproportionately represented by sequences from the Kaapvaal and Pilbara Cratons.These patterns of S-MIF attenuation and enhancement may differ from the timing and magnitude of minor sulfur isotope fractionations reported from other cratons,thus obscuring local for global sulfur cycling dynamics.By expanding the Δ^(33)S record to include the relatively underrepresented São Francisco Craton in Brazil,we suggest that marine biogeochemistry affected S-MIF preservation prior to the GOE.In an early Neoarchean sequence(2763–2730 Ma)from the Rio das Velhas Greenstone Belt,we propose that low δ^(13)Corg(<-30‰)and dampened Δ^(33)S(-0.4‰to-0.7‰)in banded iron formation reflect the marine diagenetic process of anaerobic methane oxidation.The overlying black shale(TOC up to 7.8%)with higher δ^(13)Corg(-33.4‰to-19.2‰)and expanded Δ^(33)S(2.3‰±0.8‰),recorded oxidative sulfur cycling that resulted in enhance preservation of S-MIF input from atmospheric sources of elemental sulfur.The sequence culminates in a metasandstone,where concomitant changes to more uniform δCorg(-30‰to--25‰),potentially associated with the RuBisCO I enzyme,and near-zero Δ^(33)S(-0.04‰to 0.38‰)is mainly interpreted as evidence for local oxygen production.When placed in the context of other sequences worldwide,the Rio das Velhas helps differentiate the influences of global atmospheric chemistry and local marine diagenesis in Archean biogeochemical processes.Our data suggest that prokaryotic sulfur,iron,and methane cycles might have an underestimated role in pre-GOE sulfur minor isotope records.
文摘Natural disasters such as volcanic eruptions,earthquakes,tsunamis,floods,fires,droughts,landslides and others occur frequently in most parts of our world.Therefore,many activities are being carried out to improve especially the Early Warning(EW)for disasters,but also all other phases of Disaster Management(DM)such as preparedness,awareness,response,recovery and mitigation.
文摘This special issue is part of a double special issue(Part A was published in the previous issue of this journal)dealing with the role of Geographic Information(GI)for Early Warning(EW)and Disaster Management(DM).In the editorial of Part A we gave an introduction to the topic focussing on initiatives from the EU and China and we have highlighted the importance of Digital Earth for EWand DM.We have also reflected on the outcome of some events organized by the vip editors which were important for the topic and for this special issue.
基金supported by the Hellenic Foundation for Research and Innovation(HFRI)of General Secretariat for Research and Technology(GSRT)under Grant No 651.
文摘Among the environmental threats,the intensification of natural hazards,such as soil erosion may threaten the integrity and value of cultural heritage sites.In this framework,the present study’s main objective was to identify archaeological sites susceptible by soil erosion,taking the case study of Chania prefecture in Crete Island.Remotely sensed and other available geospatial datasets were analyzed in a GIS-based empirical model,namely Unit Stream Power Erosion and Deposition(USPED),to estimate the average annual soil loss and deposition rates due to waterinduced erosion in the study area.The resultant erosion map was then intersected with the locations and surrounding zones of the known archaeological sites for identifying the sites and the portions of their vicinity being at risk.The results revealed that Chania prefecture and its cultural heritage are significantly affected by both soil loss and deposition processes.Between the two processes,soil loss was found to be more intensive,influencing a larger part of the prefecture(especially to the west)as well as a higher amount of archaeological sites.The extreme and high soil loss classes were also detected to cover the most considerable portion of the sites’surrounding area.The identification of the archaeological sites being most exposed to soil erosion hazard can constitute a basis for cultural heritage managers in order to take preventive preserva-tion measures and develop specific risk mitigation strategies.
