The studied area consists of 16 counties belonging to 3 provinces or autonomous re-gion, which are Hequ, Baode, Pianguan and Xinxian counties of Shanxi Province; Yulin,Shenmu, Fugu, Hengshan, Jingbian and Dingbian cou...The studied area consists of 16 counties belonging to 3 provinces or autonomous re-gion, which are Hequ, Baode, Pianguan and Xinxian counties of Shanxi Province; Yulin,Shenmu, Fugu, Hengshan, Jingbian and Dingbian counties of Shaanxi Province;Dongsheng, Tuoketuo, Qingshuihe counties and Yijinhuoluo, Dalate, Zhungeer banners展开更多
The authors studied the geochemistry,zircon U-Pb ages,Hf isotope of the granite porphyry and its petrogenesis and tectonic setting in the studied area. The zircon U-Pb dating indicates the formation of the granite por...The authors studied the geochemistry,zircon U-Pb ages,Hf isotope of the granite porphyry and its petrogenesis and tectonic setting in the studied area. The zircon U-Pb dating indicates the formation of the granite porphyry is in Early Cretaceous( 125. 1 ± 1. 5 Ma). The granite porphyry has high-SiO2and alkali-rich features,which belongs to high-K calc-alkaline series rocks( A / CNK = 0. 95%--1. 25%). The analyses of trace elements show the characteristics of a swallow-shaped REE distribution pattern with enrichment in LREEs and most of LILEs and HFSEs,depletion in Ba,Sr,Nb,P and Ti,and especially strong depletion in Eu,which indicates the granite porphyry belongs to the aluminous A-type granite. Their εHf( t)range from 5. 94 to 8. 80with Hf two-stage model ages( TDM2) of 620 Ma to 803 Ma. Combining with the regional tectonic background,we conclude that the source of the rocks is the new crust materials accreted from depleted mantle in Neoproterozoic and is the product of partial melting of middle and lower crustal rocks,which may be suffered from the dual impact of the subduction of the Palaeo-Pacific Ocean and the closure of the Mongol-Okhotsk Ocean.展开更多
We report the finding of the Wolitu Pb-Zn deposit in Inner Mongolia, China, through a series of geochemical surveys. The Wolitu area, located in the loess-cover area in the Hure Banner, Tongliao City,Inner Mongolia, a...We report the finding of the Wolitu Pb-Zn deposit in Inner Mongolia, China, through a series of geochemical surveys. The Wolitu area, located in the loess-cover area in the Hure Banner, Tongliao City,Inner Mongolia, and neighboring the Horqin Sandy Land to the north, had no previous history of Pb-Zn mining or record of Pb-Zn mineralization. Our study identified a large Pb-Zn anomaly with potential zones of mineralization by stream sediment survey. Random rock sampling reveals limonitization at sporadic outcrops in the gullies. The high concentrations of Pb in the residual debris provided guidelines to fix the position for exploratory trench. Oxidized concealed orebodies were identified by trenching.Blind orebodies in veins hosted within the structural zone between slates and marbles of the upper Carboniferous Shizuizi Formation and the Permian granite were discovered by drilling. It is computed that the ore reserve may reach up to 540,000 tones with Pb grade of 1.27% and Zn of 1.9%. This case study is an excellent example for identifying potential polymetallic deposits in loess covered terrains using geochemical exploration.展开更多
Grassland fires results in carbon emissions,which directly affects the carbon cycle of ecosystems and the carbon balance.The grassland area of Inner Mongolia accounts for 22%of the total grassland area in China,and ma...Grassland fires results in carbon emissions,which directly affects the carbon cycle of ecosystems and the carbon balance.The grassland area of Inner Mongolia accounts for 22%of the total grassland area in China,and many fires occur in the area every year.However,there are few models for estimation of carbon emissions from grassland fires.Accurate estimation of direct carbon emissions from grassland fires is critical to quantifying the contribution of grassland fires to the regional balance of atmospheric carbon.In this study,the regression equations for aboveground biomass(AGB)of grassland in growing season and MODIS NDVI(Normalized Difference Vegetation Index)were established through field experiments,then AGB during Nov.–Apr.were retrieved based on that in Oct.and decline rate,finally surface fuel load was obtained for whole year.Based on controlled combustion experiments of different grassland types in Inner Mongolia,the carbon emission rate of grassland fires for each grassland type were determined,then carbon emission was estimated using proposed method and carbon emission rate.Results revealed that annual average surface fuel load of grasslands in Inner Mongolia during 2000–2016 was approximately 1.1978×1012 kg.The total area of grassland which was burned in the Inner Mongolia region over the 17-year period was 5298.75 km2,with the annual average area of 311.69 km2.The spatial distribution of grassland surface fuel loads is characterized by decreasing from northeast to southwest in Inner Mongolia.The total carbon emissions from grassland fires amounted to 2.24×107 kg with an annual average of 1.32×106 for the study area.The areas with most carbon emissions were mainly concentrated in Old Barag Banner and New Barag Right Banner and on the right side of the Oroqin Autonomous Banner.The spatial characteristics of carbon emission depend on the location of grassland fire,mainly in the northeast of Inner Mongolia include Hulunbuir City,Hinggan League,Xilin Gol League and Ulanqab City.The area and spatial location of grassland fires can directly affect the total amount and spatial distribution of carbon emissions.This study provides a reference for estimating carbon emissions from steppe fires.The model and framework for estimation of carbon emissions from grassland fires established can provide a reference value for estimation of carbon emissions from grassland fires in other regions.展开更多
文摘The studied area consists of 16 counties belonging to 3 provinces or autonomous re-gion, which are Hequ, Baode, Pianguan and Xinxian counties of Shanxi Province; Yulin,Shenmu, Fugu, Hengshan, Jingbian and Dingbian counties of Shaanxi Province;Dongsheng, Tuoketuo, Qingshuihe counties and Yijinhuoluo, Dalate, Zhungeer banners
文摘The authors studied the geochemistry,zircon U-Pb ages,Hf isotope of the granite porphyry and its petrogenesis and tectonic setting in the studied area. The zircon U-Pb dating indicates the formation of the granite porphyry is in Early Cretaceous( 125. 1 ± 1. 5 Ma). The granite porphyry has high-SiO2and alkali-rich features,which belongs to high-K calc-alkaline series rocks( A / CNK = 0. 95%--1. 25%). The analyses of trace elements show the characteristics of a swallow-shaped REE distribution pattern with enrichment in LREEs and most of LILEs and HFSEs,depletion in Ba,Sr,Nb,P and Ti,and especially strong depletion in Eu,which indicates the granite porphyry belongs to the aluminous A-type granite. Their εHf( t)range from 5. 94 to 8. 80with Hf two-stage model ages( TDM2) of 620 Ma to 803 Ma. Combining with the regional tectonic background,we conclude that the source of the rocks is the new crust materials accreted from depleted mantle in Neoproterozoic and is the product of partial melting of middle and lower crustal rocks,which may be suffered from the dual impact of the subduction of the Palaeo-Pacific Ocean and the closure of the Mongol-Okhotsk Ocean.
基金granted by the China's National Mineral Resources Investigation Program (Grant No.1212011220598) the Inner Mongolia Mineral Survey Fund(Grant No.KD-05-09)
文摘We report the finding of the Wolitu Pb-Zn deposit in Inner Mongolia, China, through a series of geochemical surveys. The Wolitu area, located in the loess-cover area in the Hure Banner, Tongliao City,Inner Mongolia, and neighboring the Horqin Sandy Land to the north, had no previous history of Pb-Zn mining or record of Pb-Zn mineralization. Our study identified a large Pb-Zn anomaly with potential zones of mineralization by stream sediment survey. Random rock sampling reveals limonitization at sporadic outcrops in the gullies. The high concentrations of Pb in the residual debris provided guidelines to fix the position for exploratory trench. Oxidized concealed orebodies were identified by trenching.Blind orebodies in veins hosted within the structural zone between slates and marbles of the upper Carboniferous Shizuizi Formation and the Permian granite were discovered by drilling. It is computed that the ore reserve may reach up to 540,000 tones with Pb grade of 1.27% and Zn of 1.9%. This case study is an excellent example for identifying potential polymetallic deposits in loess covered terrains using geochemical exploration.
基金Under the auspices of National Natural Science Foundation of China (No. 4176110141771450+2 种基金41871330)National Natural Science Foundation of Inner Mongolia (No. 2017MS0409)Fundamental Research Funds for the Central Universities (No. 2412019BJ001)
文摘Grassland fires results in carbon emissions,which directly affects the carbon cycle of ecosystems and the carbon balance.The grassland area of Inner Mongolia accounts for 22%of the total grassland area in China,and many fires occur in the area every year.However,there are few models for estimation of carbon emissions from grassland fires.Accurate estimation of direct carbon emissions from grassland fires is critical to quantifying the contribution of grassland fires to the regional balance of atmospheric carbon.In this study,the regression equations for aboveground biomass(AGB)of grassland in growing season and MODIS NDVI(Normalized Difference Vegetation Index)were established through field experiments,then AGB during Nov.–Apr.were retrieved based on that in Oct.and decline rate,finally surface fuel load was obtained for whole year.Based on controlled combustion experiments of different grassland types in Inner Mongolia,the carbon emission rate of grassland fires for each grassland type were determined,then carbon emission was estimated using proposed method and carbon emission rate.Results revealed that annual average surface fuel load of grasslands in Inner Mongolia during 2000–2016 was approximately 1.1978×1012 kg.The total area of grassland which was burned in the Inner Mongolia region over the 17-year period was 5298.75 km2,with the annual average area of 311.69 km2.The spatial distribution of grassland surface fuel loads is characterized by decreasing from northeast to southwest in Inner Mongolia.The total carbon emissions from grassland fires amounted to 2.24×107 kg with an annual average of 1.32×106 for the study area.The areas with most carbon emissions were mainly concentrated in Old Barag Banner and New Barag Right Banner and on the right side of the Oroqin Autonomous Banner.The spatial characteristics of carbon emission depend on the location of grassland fire,mainly in the northeast of Inner Mongolia include Hulunbuir City,Hinggan League,Xilin Gol League and Ulanqab City.The area and spatial location of grassland fires can directly affect the total amount and spatial distribution of carbon emissions.This study provides a reference for estimating carbon emissions from steppe fires.The model and framework for estimation of carbon emissions from grassland fires established can provide a reference value for estimation of carbon emissions from grassland fires in other regions.
