Spectral data can potentially offer a rapid assessment of nutrients in leaves and reveal information about the geologic history of the soil.This study evaluated the capability of the partial least squares regression(P...Spectral data can potentially offer a rapid assessment of nutrients in leaves and reveal information about the geologic history of the soil.This study evaluated the capability of the partial least squares regression(PLSR)for estimating foliar macro-and micronutrients(Ca,Mg,K,P,Mn,and Zn)using spectral data(400 to 2,450 nm).First,filter-based wavelength selection was conducted to reduce the independent variables.PLSR performance was then assessed across 4 geologic materials(coarse glacial till,glaciofluvial,melt-out till,and outwash)and 4 dominant tree genera(Acer,Betula,Fagus,and Quercus)in the northeastern United States.The spectral ranges 400 to 500 nm and 1,800 to 2,450 nm were found to be the most important spectral regions for estimating foliar nutrient concentrations.The developed PLSR model predicted 6 foliar nutrients with moderate to high accuracy(adjusted R^(2) from 0.60 to 0.75).Foliar macronutrient concentrations were estimated with higher accuracy(mean adj.R^(2)=0.69)than micronutrient concentrations(mean adj.R^(2)=0.635).The prediction for the individual tree genera group and the individual geologic materials group outperformed the combined group;for instance,the adj.R^(2) for estimating Ca and P was 39%higher for American beech(Fagus grandifolia)than all tree genera combined.Spectral measurements combined with wavelength selection and PLSR models can potentially be used to quantify foliar macro-and micronutrients at regional scales,and taking into account geologic materials and tree genera will improve this prediction.展开更多
"Golden triangle"area bordered on Yunnan-Guizhou-Guangxi was one of the most important Carlin-type gold deposits concentration areas.Deep understanding of Carlin-type gold deposits in Guizhou and Guangxi Pro..."Golden triangle"area bordered on Yunnan-Guizhou-Guangxi was one of the most important Carlin-type gold deposits concentration areas.Deep understanding of Carlin-type gold deposits in Guizhou and Guangxi Province had reached through several decades studies,but geological environment was very complex in the southeastern Yunnan,and Carlin-type gold deposits produced in the southeastern Yunnan were different from that of America,few studies were taken there.Based on a large number of field work,studies on the geological characteristics combining with geochemistry characteristics were taken,and analysis the genesis of Laozhaiwan gold deposit.The types of alteration in Laozhaiwan gold deposit were mainly silicification and pyritization,and Gold grade was high when silicification and pyritization were both occurred.It could be caculated that fluid density(g/cm3)varied from 0.7 to 4.9,salinity varied from 0.76%to 0.95%and ore-forming pressure(Pa)varied from 1.81×105 to 49.96×105 according to fluid inclusion test results,showed that Laozhaiwan gold deposit was hypabyssal hydrothermal deposit in low temperature and low salinity.According to composition of fluid inclusion analysis,combining with H-O isotope,made theδD-δ18O figure,showed that the fluid of the deposit rooted in formation water and mixed with meteoric waters later.展开更多
Since the start of the 21st century,health issues caused by exposure to geological materials,such as heavy metal pollution and/or imbalances in essential elements,have consistently affected about one billion people wo...Since the start of the 21st century,health issues caused by exposure to geological materials,such as heavy metal pollution and/or imbalances in essential elements,have consistently affected about one billion people worldwide.In response to this critical problem,the field of Medical Geology has developed through collaborative efforts from experts in various disciplines,including geologists,environmental scientists,biologists,biochemists,toxicologists,epidemiologists,and public health professionals.展开更多
Based on elasto-plasticity and damage mechanics, a double-medium constitutive model of geological material under uniaxial tension and compression was presented, on the assumption that rock and soil materials are the p...Based on elasto-plasticity and damage mechanics, a double-medium constitutive model of geological material under uniaxial tension and compression was presented, on the assumption that rock and soil materials are the pore-fracture double-medium, and porous medium has no damage occurring, while fracture medium has damage occurring with load. To the implicit equation of the model, iterative method was adopted to obtain the complete stress-strain curve of the material. The result shows that many different distributions （uniform distribution, concentrated distribution and random distribution） of fractures in rock and soil material are the essential reasons of the daedal constitutive relations. By the reason that the double-medium constitutive model separates the material to be porous medium part, which is the main body of elasticity, and fracture medium part, which is the main body of damage, it is of important practical values and theoretical meanings to the study on failure of rock and soil or materials containing damage.展开更多
Based on a shallow roadway with weakly cemented soft strata in western China, this paper studies the range and degree of plastic zones in soft strata roadways with weak cementation. Geological radars were used to moni...Based on a shallow roadway with weakly cemented soft strata in western China, this paper studies the range and degree of plastic zones in soft strata roadways with weak cementation. Geological radars were used to monitor the loose range and level of surrounding rocks. A mechanical model of weakly cemented roadway was established, including granular material based on the measured results. The model was then used to determine the plastic zone radium. The predicted results agree well with measured results which provide valuable theoretical references for the analysis of surrounding rock stability and support reinforcing design of weakly cemented roadways. Finally, a combined supporting scheme of whole section bolting and grouting was proposed based on the original supporting scheme. It is proved that this support plan can effectively control the deformation and plastic zone expansion of the roadway surrounding rock and thus ensure the long-term stable and safe mining.展开更多
Some case studies are presented ranging from geological fakes and frauds,homicides and one environmental forensic case.Fakes may be true geological materials such as created fossils or gems and precious stones,or wher...Some case studies are presented ranging from geological fakes and frauds,homicides and one environmental forensic case.Fakes may be true geological materials such as created fossils or gems and precious stones,or where geological methods are used to analyse fakes,such as the stones or ceramics used in making archaeological or art forgeries(e.g.,mineral pigments in paintings).Fakes have also been created for reasons of academic rivalry,career advancement and religious belief.Fraud commonly involves over-stated claims of ore content associated with mining and the oil and gas industry.The range of geological fakes,the uses of geological methods in detecting fakes,and the extent of fraud in the mining sector are all extensive and sometimes incredible.The homicide is case presented to demonstrate how the types of geological investigation described in the rest of this volume may be applied.We include an environmental forensic case for similar reasons,to show that forensic geology may be applied to more than homicides and fakery.展开更多
基金supported by the University of Massachusetts Amherst,College of Natural Sciences by Award 1801 to J.B.R.
文摘Spectral data can potentially offer a rapid assessment of nutrients in leaves and reveal information about the geologic history of the soil.This study evaluated the capability of the partial least squares regression(PLSR)for estimating foliar macro-and micronutrients(Ca,Mg,K,P,Mn,and Zn)using spectral data(400 to 2,450 nm).First,filter-based wavelength selection was conducted to reduce the independent variables.PLSR performance was then assessed across 4 geologic materials(coarse glacial till,glaciofluvial,melt-out till,and outwash)and 4 dominant tree genera(Acer,Betula,Fagus,and Quercus)in the northeastern United States.The spectral ranges 400 to 500 nm and 1,800 to 2,450 nm were found to be the most important spectral regions for estimating foliar nutrient concentrations.The developed PLSR model predicted 6 foliar nutrients with moderate to high accuracy(adjusted R^(2) from 0.60 to 0.75).Foliar macronutrient concentrations were estimated with higher accuracy(mean adj.R^(2)=0.69)than micronutrient concentrations(mean adj.R^(2)=0.635).The prediction for the individual tree genera group and the individual geologic materials group outperformed the combined group;for instance,the adj.R^(2) for estimating Ca and P was 39%higher for American beech(Fagus grandifolia)than all tree genera combined.Spectral measurements combined with wavelength selection and PLSR models can potentially be used to quantify foliar macro-and micronutrients at regional scales,and taking into account geologic materials and tree genera will improve this prediction.
基金financially supported by the Program of National Natural Science Foundation of China(No.41372093No.40930423+2 种基金No.41171302)the work item of China Geological Survey(No.12120113036200)higher education quality engineering project of chalcography excellent textbook Construction(No.XJC1105)
文摘"Golden triangle"area bordered on Yunnan-Guizhou-Guangxi was one of the most important Carlin-type gold deposits concentration areas.Deep understanding of Carlin-type gold deposits in Guizhou and Guangxi Province had reached through several decades studies,but geological environment was very complex in the southeastern Yunnan,and Carlin-type gold deposits produced in the southeastern Yunnan were different from that of America,few studies were taken there.Based on a large number of field work,studies on the geological characteristics combining with geochemistry characteristics were taken,and analysis the genesis of Laozhaiwan gold deposit.The types of alteration in Laozhaiwan gold deposit were mainly silicification and pyritization,and Gold grade was high when silicification and pyritization were both occurred.It could be caculated that fluid density(g/cm3)varied from 0.7 to 4.9,salinity varied from 0.76%to 0.95%and ore-forming pressure(Pa)varied from 1.81×105 to 49.96×105 according to fluid inclusion test results,showed that Laozhaiwan gold deposit was hypabyssal hydrothermal deposit in low temperature and low salinity.According to composition of fluid inclusion analysis,combining with H-O isotope,made theδD-δ18O figure,showed that the fluid of the deposit rooted in formation water and mixed with meteoric waters later.
文摘Since the start of the 21st century,health issues caused by exposure to geological materials,such as heavy metal pollution and/or imbalances in essential elements,have consistently affected about one billion people worldwide.In response to this critical problem,the field of Medical Geology has developed through collaborative efforts from experts in various disciplines,including geologists,environmental scientists,biologists,biochemists,toxicologists,epidemiologists,and public health professionals.
基金Project supported by the National Natural Science Foundation of China (No.50374041)the National Key Project of the Tenth Five-Year Plan of China (No.2001BA803B0404)
文摘Based on elasto-plasticity and damage mechanics, a double-medium constitutive model of geological material under uniaxial tension and compression was presented, on the assumption that rock and soil materials are the pore-fracture double-medium, and porous medium has no damage occurring, while fracture medium has damage occurring with load. To the implicit equation of the model, iterative method was adopted to obtain the complete stress-strain curve of the material. The result shows that many different distributions （uniform distribution, concentrated distribution and random distribution） of fractures in rock and soil material are the essential reasons of the daedal constitutive relations. By the reason that the double-medium constitutive model separates the material to be porous medium part, which is the main body of elasticity, and fracture medium part, which is the main body of damage, it is of important practical values and theoretical meanings to the study on failure of rock and soil or materials containing damage.
基金provided by the National 973 Programs(No.2014CB046905)the National Natural Science Foundation of China(Nos.51274191 and 51404245)+1 种基金the Doctoral Fund of Ministry of Education(No.20130095110018)China Postdoctoral Science Foundation(No.2014M551699)
文摘Based on a shallow roadway with weakly cemented soft strata in western China, this paper studies the range and degree of plastic zones in soft strata roadways with weak cementation. Geological radars were used to monitor the loose range and level of surrounding rocks. A mechanical model of weakly cemented roadway was established, including granular material based on the measured results. The model was then used to determine the plastic zone radium. The predicted results agree well with measured results which provide valuable theoretical references for the analysis of surrounding rock stability and support reinforcing design of weakly cemented roadways. Finally, a combined supporting scheme of whole section bolting and grouting was proposed based on the original supporting scheme. It is proved that this support plan can effectively control the deformation and plastic zone expansion of the roadway surrounding rock and thus ensure the long-term stable and safe mining.
文摘Some case studies are presented ranging from geological fakes and frauds,homicides and one environmental forensic case.Fakes may be true geological materials such as created fossils or gems and precious stones,or where geological methods are used to analyse fakes,such as the stones or ceramics used in making archaeological or art forgeries(e.g.,mineral pigments in paintings).Fakes have also been created for reasons of academic rivalry,career advancement and religious belief.Fraud commonly involves over-stated claims of ore content associated with mining and the oil and gas industry.The range of geological fakes,the uses of geological methods in detecting fakes,and the extent of fraud in the mining sector are all extensive and sometimes incredible.The homicide is case presented to demonstrate how the types of geological investigation described in the rest of this volume may be applied.We include an environmental forensic case for similar reasons,to show that forensic geology may be applied to more than homicides and fakery.
