Geochemical characteristics of the Chagande＇ersi molybdenum deposit in Inner Mongolia and its genesis were analyzed in this study using rock mineralography and rock geochemical testing. The mineralized country rocks ...Geochemical characteristics of the Chagande＇ersi molybdenum deposit in Inner Mongolia and its genesis were analyzed in this study using rock mineralography and rock geochemical testing. The mineralized country rocks of the Chagande＇ersi molybdenum deposit consist mainly of medium- to fine-grained monzogranite, medium-to fine-grained rich-K granite, with minor fine-grained K- feldspar granite veins and quartz veins. The rocks are characterized by high silica, rich alkali, high potassium, which are favorable factors for molybdenum mineralization. The rocks have the Rittmann index ranging from 1.329 to 1.961, an average Na20＋K20 value of 7.41, and AI2Oa/（CaO＋Na20＋K^O） 〉1, suggesting that the rocks belong to the high-K calc-alkaline peraluminous granite. The typical rock samples are enriched in Rb, Th, K and light rare earth elements, depleted in Sr, Ba, Nb, P and Ti, and these features are similar to that of the melt granite resulting from collision of plate margins. The JEu of the rocks falls the zone between the crust granite and crust-mantle granite, and are close to that of the crust granite; （La/LU）N indicates the formation environment of granite is a continental margin setting. The Nb/Ta ratios are close to that of the average crust （10）; the Zr/Hf ratios of monzogranite are partly below the mean mantle （34-60）, while the Zr/Hf ratio of K-feldspar granite are close to the mean value in the crust. Comprehensive analyses show that the granite in this area formed during the transition period between tectonic collision and post-collision. During the plate collision and orogeny, the crust and mantle material were mixed physically, remelting into lava and then crystal fractionation, finally gave rise to the formation of the rock body in this area. This has close spatial and temporal relation with the molybdenum mineralization.展开更多
A differential fatherhood premium exists among selected groups of fathers of various socio-economic backgrounds. Besides marital status, residential arrangement, biological paternity, and other demographic dimensions,...A differential fatherhood premium exists among selected groups of fathers of various socio-economic backgrounds. Besides marital status, residential arrangement, biological paternity, and other demographic dimensions, the mechanisms associated with fathers＇ structural characteristics of work that produce divergent labor market outcomes are less well understood. The authors leveraged the cases of productivity and specialization, family and responsibility, and compensating differentials and examined the impacts of work context and occupational characteristics on the pay gap between fathers and non-fathers Based on joint data from the 1997-2015 National Longitudinal Survey of Youth （NLSY97） and Occupational Information Network （O＇NET） （n -- 37,138）, the authors used fixed-effects models to estimate the associations between job features and the fatherhood premium. The regression results showed that occupations entailing competition and requiring on-the-job training are associated with more wage bonus; occupations offering inflexible schedule are associated with less wage gain These work-related characteristics further emphasize fathers＇ work structure and context, human capital accumulation, and work-family conflict. Overall, these findings are consistent with the theoretical perspectives of productivity and specialization and compensating differentials, adding new evidences to the structural explanations of the fatherhood premium.展开更多
基金supported by the National Natural Science Foundation,40073013
文摘Geochemical characteristics of the Chagande＇ersi molybdenum deposit in Inner Mongolia and its genesis were analyzed in this study using rock mineralography and rock geochemical testing. The mineralized country rocks of the Chagande＇ersi molybdenum deposit consist mainly of medium- to fine-grained monzogranite, medium-to fine-grained rich-K granite, with minor fine-grained K- feldspar granite veins and quartz veins. The rocks are characterized by high silica, rich alkali, high potassium, which are favorable factors for molybdenum mineralization. The rocks have the Rittmann index ranging from 1.329 to 1.961, an average Na20＋K20 value of 7.41, and AI2Oa/（CaO＋Na20＋K^O） 〉1, suggesting that the rocks belong to the high-K calc-alkaline peraluminous granite. The typical rock samples are enriched in Rb, Th, K and light rare earth elements, depleted in Sr, Ba, Nb, P and Ti, and these features are similar to that of the melt granite resulting from collision of plate margins. The JEu of the rocks falls the zone between the crust granite and crust-mantle granite, and are close to that of the crust granite; （La/LU）N indicates the formation environment of granite is a continental margin setting. The Nb/Ta ratios are close to that of the average crust （10）; the Zr/Hf ratios of monzogranite are partly below the mean mantle （34-60）, while the Zr/Hf ratio of K-feldspar granite are close to the mean value in the crust. Comprehensive analyses show that the granite in this area formed during the transition period between tectonic collision and post-collision. During the plate collision and orogeny, the crust and mantle material were mixed physically, remelting into lava and then crystal fractionation, finally gave rise to the formation of the rock body in this area. This has close spatial and temporal relation with the molybdenum mineralization.
文摘A differential fatherhood premium exists among selected groups of fathers of various socio-economic backgrounds. Besides marital status, residential arrangement, biological paternity, and other demographic dimensions, the mechanisms associated with fathers＇ structural characteristics of work that produce divergent labor market outcomes are less well understood. The authors leveraged the cases of productivity and specialization, family and responsibility, and compensating differentials and examined the impacts of work context and occupational characteristics on the pay gap between fathers and non-fathers Based on joint data from the 1997-2015 National Longitudinal Survey of Youth （NLSY97） and Occupational Information Network （O＇NET） （n -- 37,138）, the authors used fixed-effects models to estimate the associations between job features and the fatherhood premium. The regression results showed that occupations entailing competition and requiring on-the-job training are associated with more wage bonus; occupations offering inflexible schedule are associated with less wage gain These work-related characteristics further emphasize fathers＇ work structure and context, human capital accumulation, and work-family conflict. Overall, these findings are consistent with the theoretical perspectives of productivity and specialization and compensating differentials, adding new evidences to the structural explanations of the fatherhood premium.
