The Jiuyishan complex massif,located in the northern section of the Nanling region,is a combination of five plutons,namely,the Xuehuading,Jinjiling,Pangxiemu,Shaziling and Xishan plutons.Whole-rock geochemistry,Iminer...The Jiuyishan complex massif,located in the northern section of the Nanling region,is a combination of five plutons,namely,the Xuehuading,Jinjiling,Pangxiemu,Shaziling and Xishan plutons.Whole-rock geochemistry,Imineral electron microprobe analysis,zircon U-Pb dating and Hf isotope analysis were carried out for the Jinjiling and Pangxiemu plutons.The zircon U-Pb dating yields weighted mean ages of 152.9±0.9 Ma for the Jinjiling pluton and 151.7±1.5 Ma for the Pangxiemu pluton,with a narrow gap between them.The Jinjiling and Pangxiemu plutons both have geochemical characteristics of high SiO2,Al2 O3,Na2 O,K2 O and low TiO2,MgO,CaO,P2 O5 contents,with intense depletions in Sr,Ba,Ti,Eu and enrichments in Ga,FeoOT and HFSE,and these characteristics reflect an A-type affinity.From the Jinjiling to the Pangxiemu plutons,the mineral composition of mica changes from lepidomelane to zinnwaldite,with increases in F,Li2 O and Rb2 O contents.The mineral composition of zircon changes from low Zr/Hf to high Zr/Hf,with increasing HfO2,P2 O5 and UO2+ThO2+Y2 O3 contents.The mineral compositions of feldspar indicate that the Pangxiemu pluton contains more alkali feldspar than the Jinjiling pluton.The whole-rock geochemistry and mineral compositions reveal a higher degree of differentiation for the Pangxiemu pluton.The nearly uniformεHf(t)indicates the same source region for the two plutons:both were derived from partial melting of the lower crust,with small contributions of mantle materials.In addition,higher F,lower Nb/Ta and Zr/Hf ratios in the Pangxiemu Pluton suggest a closer relationship with the rare metal mineralization than for the Jinjiling pluton.展开更多
Aims Plants generally respond to nitrogen(N)fertilization with increased growth,but N addition can also suppress rhizosphere effects,which consequently alters soil processes.We quantified the influence of N addition o...Aims Plants generally respond to nitrogen(N)fertilization with increased growth,but N addition can also suppress rhizosphere effects,which consequently alters soil processes.We quantified the influence of N addition on rhizosphere effects of two C4 grasses:smooth crabgrass(Digitaria ischaemum)and bermudagrass(Cynodon dactylon).Methods Plants were grown in nutrient-poor soil for 80 days with either 20 or 120μg NH4No3-N g dry soil−1.N mineralization rates,microbial biomass,extracellular enzyme activities and bacterial community structure were measured on both rhizosphere and bulk(unplanted)soils after plant harvest.Important Findings Fertilization showed nominal differences in net N mineralization,extracellular enzyme activity and microbial biomass between the rhizosphere and bulk soils,indicating minimal influence of N on rhizosphere effects.Instead,the presence of plant roots showed the strongest impact(up to 80%)on rates of net N mineralization and activities of three soil enzymes indicative of N release from organic matter.Principal component analysis of terminal restriction fragment length polymorphism(t-rFlP)also reflected these trends by highlighting the importance of plant roots in structuring the soil bacterial community,followed by plant species and N fertilization(to a minor extent).overall,the results indicate minor contributions of short-term N fertilization to changes in the magnitude of rhizos-phere effects for both grass species.展开更多
We analyzed the major and trace element chemical compositions of 66 granitic rocks from 15 different areas in Japan. The intrusions from which the samples were collected were associated with Pb-Zn, Mo, Cu-Fe, Sn, or W...We analyzed the major and trace element chemical compositions of 66 granitic rocks from 15 different areas in Japan. The intrusions from which the samples were collected were associated with Pb-Zn, Mo, Cu-Fe, Sn, or W mineralization and, for comparison, samples were also collected from intrusions not associated with any metal mineralization. The analyses indicated that the granitic rocks associated with Pb-Zn, Mo, or Cu-Fe mineralization were granites, granodiorites, or diorites, and that they were all I-type and formed in a volcanic arc tectonic setting. The granitic rocks associated with Sn or W mineralization and barren granitic rocks were classified as granites and as I-type with the exception of a few S-type granitic rocks. Most of the Sn- or W-associated granitic rocks and barren granitic rocks are thought to have formed in a volcanic arc tectonic setting. The Pb-Zn-, Mo-, or Cu-Fe-associated granitic rocks rarely shows negative Eu anomalies and a few of them are adakitic rocks, whereas all of the Sn- or W-associated granitic rocks and barren granitic rocks show negative Eu anomalies. For these Japanese granitic rocks, the contents of K2O, La, Y, Rb, Ta, Pb, Th, U, and REEs other than Eu increase with increasing SiO2. Conversely, the contents of major components other than Na2O and K2O and the trace components V, Zn, Sr, Eu, and Sc decrease with increasing SiO2. The Zr, Sn, and Hf abundances increase with increasing SiO2 up to 70 wt%, but their abundances decrease when the SiO2 exceeds 70 wt%. This suggests that granitic magma is saturated with these elements at 70 wt% of SiO2, approximately.展开更多
The rhizosphere priming effect(RPE)is increasingly being considered to be an important regulator of soil organic matter(SOM)decomposition and nutrient turnover,with potential importance for the global CO_(2) budget.As...The rhizosphere priming effect(RPE)is increasingly being considered to be an important regulator of soil organic matter(SOM)decomposition and nutrient turnover,with potential importance for the global CO_(2) budget.As a result,studies on the RPE have rapidly increased in number over the last few years.Most of these experiments have been performed using unplanted soil as the control,which could potentially lead to incorrect assessment of the RPE.Therefore,we performed a greenhouse experiment to investigate how the choice of control(i.e.,unplanted control and planted control)influenced the quantification of RPE on SOM decomposition and gross nitrogen(N)mineralization,and to link this to differences in microbial and abiotic soil properties between the two controls.In the planted control,planted seedlings were cut at soil surface 5 d before measurement of the RPE.The RPE on SOM decomposition was positive in pine soil and almost 2-fold higher when calculated from the planted control than from the unplanted control.In spruce soil,a negative RPE on SOM decomposition was found when calculated from the planted control,while the RPE was positive when calculated from the unplanted control.No RPE on gross N mineralization was found when calculated from the planted control,while a positive RPE of more than 100%was found when calculated from the unplanted control.The microbial biomass and growth rate were lower,while the inorganic N content was higher in the unplanted control than in the planted control.The microbial community composition and potential enzyme activity in the planted treatment and planted control were similar,but they differed significantly from those in the unplanted control.The results showed that the RPE varied widely depending on the choice of control;thus,we suggest that a planted control,in which the aboveground plant parts are removed only a few days before the measurement of RPE,should be used as the control when elucidating the RPE on belowground C and N cycling responses to environmental change.展开更多
基金financially supported by the Key R&D Program of China(Grant No.2017YFC0602402)the Innovationdriven Plan of Central South University,China(Grant No.2015CX008)+2 种基金the China Postdoctoral Science Foundation(Grant No.2017M622597)Open Research Fund Program of Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University),Ministry of Education(Grant No.2019YSJS23)the Natural Science Foundation of Hunan Province(Grant No.2017JJ3138)
文摘The Jiuyishan complex massif,located in the northern section of the Nanling region,is a combination of five plutons,namely,the Xuehuading,Jinjiling,Pangxiemu,Shaziling and Xishan plutons.Whole-rock geochemistry,Imineral electron microprobe analysis,zircon U-Pb dating and Hf isotope analysis were carried out for the Jinjiling and Pangxiemu plutons.The zircon U-Pb dating yields weighted mean ages of 152.9±0.9 Ma for the Jinjiling pluton and 151.7±1.5 Ma for the Pangxiemu pluton,with a narrow gap between them.The Jinjiling and Pangxiemu plutons both have geochemical characteristics of high SiO2,Al2 O3,Na2 O,K2 O and low TiO2,MgO,CaO,P2 O5 contents,with intense depletions in Sr,Ba,Ti,Eu and enrichments in Ga,FeoOT and HFSE,and these characteristics reflect an A-type affinity.From the Jinjiling to the Pangxiemu plutons,the mineral composition of mica changes from lepidomelane to zinnwaldite,with increases in F,Li2 O and Rb2 O contents.The mineral composition of zircon changes from low Zr/Hf to high Zr/Hf,with increasing HfO2,P2 O5 and UO2+ThO2+Y2 O3 contents.The mineral compositions of feldspar indicate that the Pangxiemu pluton contains more alkali feldspar than the Jinjiling pluton.The whole-rock geochemistry and mineral compositions reveal a higher degree of differentiation for the Pangxiemu pluton.The nearly uniformεHf(t)indicates the same source region for the two plutons:both were derived from partial melting of the lower crust,with small contributions of mantle materials.In addition,higher F,lower Nb/Ta and Zr/Hf ratios in the Pangxiemu Pluton suggest a closer relationship with the rare metal mineralization than for the Jinjiling pluton.
基金United States Department of Agriculture National Institute of Food and Agriculture Hatch program(NYC-145403)the New York State Turfgrass Association and the US Department of Energy,Office of Science,Office of Biological and Environmental Research Terrestrial Ecosystem Science Program(DE-AC02-05CH11231).
文摘Aims Plants generally respond to nitrogen(N)fertilization with increased growth,but N addition can also suppress rhizosphere effects,which consequently alters soil processes.We quantified the influence of N addition on rhizosphere effects of two C4 grasses:smooth crabgrass(Digitaria ischaemum)and bermudagrass(Cynodon dactylon).Methods Plants were grown in nutrient-poor soil for 80 days with either 20 or 120μg NH4No3-N g dry soil−1.N mineralization rates,microbial biomass,extracellular enzyme activities and bacterial community structure were measured on both rhizosphere and bulk(unplanted)soils after plant harvest.Important Findings Fertilization showed nominal differences in net N mineralization,extracellular enzyme activity and microbial biomass between the rhizosphere and bulk soils,indicating minimal influence of N on rhizosphere effects.Instead,the presence of plant roots showed the strongest impact(up to 80%)on rates of net N mineralization and activities of three soil enzymes indicative of N release from organic matter.Principal component analysis of terminal restriction fragment length polymorphism(t-rFlP)also reflected these trends by highlighting the importance of plant roots in structuring the soil bacterial community,followed by plant species and N fertilization(to a minor extent).overall,the results indicate minor contributions of short-term N fertilization to changes in the magnitude of rhizos-phere effects for both grass species.
文摘We analyzed the major and trace element chemical compositions of 66 granitic rocks from 15 different areas in Japan. The intrusions from which the samples were collected were associated with Pb-Zn, Mo, Cu-Fe, Sn, or W mineralization and, for comparison, samples were also collected from intrusions not associated with any metal mineralization. The analyses indicated that the granitic rocks associated with Pb-Zn, Mo, or Cu-Fe mineralization were granites, granodiorites, or diorites, and that they were all I-type and formed in a volcanic arc tectonic setting. The granitic rocks associated with Sn or W mineralization and barren granitic rocks were classified as granites and as I-type with the exception of a few S-type granitic rocks. Most of the Sn- or W-associated granitic rocks and barren granitic rocks are thought to have formed in a volcanic arc tectonic setting. The Pb-Zn-, Mo-, or Cu-Fe-associated granitic rocks rarely shows negative Eu anomalies and a few of them are adakitic rocks, whereas all of the Sn- or W-associated granitic rocks and barren granitic rocks show negative Eu anomalies. For these Japanese granitic rocks, the contents of K2O, La, Y, Rb, Ta, Pb, Th, U, and REEs other than Eu increase with increasing SiO2. Conversely, the contents of major components other than Na2O and K2O and the trace components V, Zn, Sr, Eu, and Sc decrease with increasing SiO2. The Zr, Sn, and Hf abundances increase with increasing SiO2 up to 70 wt%, but their abundances decrease when the SiO2 exceeds 70 wt%. This suggests that granitic magma is saturated with these elements at 70 wt% of SiO2, approximately.
基金funded by the Swedish Research Council(No.2016-04710,2016)the Knut and Alice Wallenberg Foundation,Sweden(No.2013.0073)+1 种基金China Postdoctoral Science Foundation(No.2021M703135)supported by the Chinese Scholarship Council。
文摘The rhizosphere priming effect(RPE)is increasingly being considered to be an important regulator of soil organic matter(SOM)decomposition and nutrient turnover,with potential importance for the global CO_(2) budget.As a result,studies on the RPE have rapidly increased in number over the last few years.Most of these experiments have been performed using unplanted soil as the control,which could potentially lead to incorrect assessment of the RPE.Therefore,we performed a greenhouse experiment to investigate how the choice of control(i.e.,unplanted control and planted control)influenced the quantification of RPE on SOM decomposition and gross nitrogen(N)mineralization,and to link this to differences in microbial and abiotic soil properties between the two controls.In the planted control,planted seedlings were cut at soil surface 5 d before measurement of the RPE.The RPE on SOM decomposition was positive in pine soil and almost 2-fold higher when calculated from the planted control than from the unplanted control.In spruce soil,a negative RPE on SOM decomposition was found when calculated from the planted control,while the RPE was positive when calculated from the unplanted control.No RPE on gross N mineralization was found when calculated from the planted control,while a positive RPE of more than 100%was found when calculated from the unplanted control.The microbial biomass and growth rate were lower,while the inorganic N content was higher in the unplanted control than in the planted control.The microbial community composition and potential enzyme activity in the planted treatment and planted control were similar,but they differed significantly from those in the unplanted control.The results showed that the RPE varied widely depending on the choice of control;thus,we suggest that a planted control,in which the aboveground plant parts are removed only a few days before the measurement of RPE,should be used as the control when elucidating the RPE on belowground C and N cycling responses to environmental change.
