Cenozoic volcanic rocks, forming a series of volcanic rocks platform or highland on different sub\|volcanic rocks belt, had distributed widely in northern Qinghai—Tibet plateau, and characterized by potassinm\|rich l...Cenozoic volcanic rocks, forming a series of volcanic rocks platform or highland on different sub\|volcanic rocks belt, had distributed widely in northern Qinghai—Tibet plateau, and characterized by potassinm\|rich lavas which main petrologic types are latidacite and latite. The petrogenesis of volcanic rocks in northern Tibetan plateau had been well\|studied, and thought they play an important role to uplift of Tibetan plateau. Based on the study of lithochemistry and isotopic age determination of the rocks in Qiangtang area, which is the most southern and earliest volcanic rocks belt of Cenozoic volcanic rocks, I contribute another view here to the early uplift of Tibetan plateau. Cenozoic volcanic rocks in Qiangtang region, thickness of the rocks are from 200 to 1000m in different area, belong to shoshonite and high\|K calc\|alkaline series, highly enrich alkaline specially enrich potassinm, large\|ion lithophytes elements (Rb,Sr,Ba,and Th), LREE and deplete high\|field strength elements (Ta,Er,Hf,and Ti). Chondrite\|normalized REE pattern of volcanic rocks show an absence of significant Eu anomaly, and indicate that the volcanic source was plagioclase\|free and probably resulted from melting in lower crust or upper mantle. Cenozoic volcanic rocks in Qiangtang region are similar petrologic and geochemical characteristics to that have been reported in more northern Hoh Xil and Kunlun area in Tibetan plateau. The age scope of volcanic rocks in Qiangtang area were from 44.1～32.6Ma, among which the age mainly were 44.1～42.5Ma, which belong to mid\|Eocene epoch to primary Oligocene epoch, and could be classified into four out pouring periods, according to the potassium\|argon age dating. The study on lithochemistry and age of the rocks in Qiangtang area suggest that Intracontinental subduction southward Qiangtang tectonic belt plays an important role to Cenozoic volcanism, and imply that the convective removal of the thicked lithosphere, which formed at the collision mountain\|building processes, are responsible for the formation of Cenozoic volcanic rocks, the earliest uplift of Tibetan plateau. and regional extension in Qiangtang area.展开更多
Because potassium(K)is a rock-derived essential element that can be depleted in highly-weathered tropical soils,K availability may limit some portion of soil microbial activity in tropical forest ecosystems.In this pa...Because potassium(K)is a rock-derived essential element that can be depleted in highly-weathered tropical soils,K availability may limit some portion of soil microbial activity in tropical forest ecosystems.In this paper we tested if K limits microbial activity in the condition of sufficient labile C supply.An incubation experiment was performed using surface soil samples(0–10 cm depth)obtained from four permanent ecological research plots in a natural sub-tropical forest in southern China.Soil samples were taken in September 2016.Heterotrophic soil respiration rates and microbial biomass were measured after the addition of glucose(both D and L)with and without K(potassium chloride).We did not observe any effects of K addition on soil microbial respiration,suggesting that K does not limit the microbial activity in the condition of sufficient labile C supply.The lack of microbial response to added K can be attributed to the high mobility of K in forest ecosystems,which may have provided sufficient K to microbes in our soil samples(already provided at the beginning of the incubation).However,at the present stage,we cannot conclude that K is not a limiting factor of soil microbial activity in other tropical forest ecosystems because of the heterogeneity of tropical forest ecosystems and few observations.The hypothesis needs to be tested in larger numbers of tropical forests.展开更多
1 Introduction The Gremyachinskoye potassium salt field lies within the Safronovskaya area and is confined to the preoverthrust zone–the 20-25 kilometer band conventionally recognized in the southern termination of t...1 Introduction The Gremyachinskoye potassium salt field lies within the Safronovskaya area and is confined to the preoverthrust zone–the 20-25 kilometer band conventionally recognized in the southern termination of the Volga展开更多
文摘Cenozoic volcanic rocks, forming a series of volcanic rocks platform or highland on different sub\|volcanic rocks belt, had distributed widely in northern Qinghai—Tibet plateau, and characterized by potassinm\|rich lavas which main petrologic types are latidacite and latite. The petrogenesis of volcanic rocks in northern Tibetan plateau had been well\|studied, and thought they play an important role to uplift of Tibetan plateau. Based on the study of lithochemistry and isotopic age determination of the rocks in Qiangtang area, which is the most southern and earliest volcanic rocks belt of Cenozoic volcanic rocks, I contribute another view here to the early uplift of Tibetan plateau. Cenozoic volcanic rocks in Qiangtang region, thickness of the rocks are from 200 to 1000m in different area, belong to shoshonite and high\|K calc\|alkaline series, highly enrich alkaline specially enrich potassinm, large\|ion lithophytes elements (Rb,Sr,Ba,and Th), LREE and deplete high\|field strength elements (Ta,Er,Hf,and Ti). Chondrite\|normalized REE pattern of volcanic rocks show an absence of significant Eu anomaly, and indicate that the volcanic source was plagioclase\|free and probably resulted from melting in lower crust or upper mantle. Cenozoic volcanic rocks in Qiangtang region are similar petrologic and geochemical characteristics to that have been reported in more northern Hoh Xil and Kunlun area in Tibetan plateau. The age scope of volcanic rocks in Qiangtang area were from 44.1～32.6Ma, among which the age mainly were 44.1～42.5Ma, which belong to mid\|Eocene epoch to primary Oligocene epoch, and could be classified into four out pouring periods, according to the potassium\|argon age dating. The study on lithochemistry and age of the rocks in Qiangtang area suggest that Intracontinental subduction southward Qiangtang tectonic belt plays an important role to Cenozoic volcanism, and imply that the convective removal of the thicked lithosphere, which formed at the collision mountain\|building processes, are responsible for the formation of Cenozoic volcanic rocks, the earliest uplift of Tibetan plateau. and regional extension in Qiangtang area.
基金financially supported by National Natural Science Foundation of China(NO.41731176,41650110484,)Grant-in-Aid for JSPS Postdoctoral Fellowships for Research Abroad(28 601)the Youth Innovation Promotion Association,CAS(No.2015287)
文摘Because potassium(K)is a rock-derived essential element that can be depleted in highly-weathered tropical soils,K availability may limit some portion of soil microbial activity in tropical forest ecosystems.In this paper we tested if K limits microbial activity in the condition of sufficient labile C supply.An incubation experiment was performed using surface soil samples(0–10 cm depth)obtained from four permanent ecological research plots in a natural sub-tropical forest in southern China.Soil samples were taken in September 2016.Heterotrophic soil respiration rates and microbial biomass were measured after the addition of glucose(both D and L)with and without K(potassium chloride).We did not observe any effects of K addition on soil microbial respiration,suggesting that K does not limit the microbial activity in the condition of sufficient labile C supply.The lack of microbial response to added K can be attributed to the high mobility of K in forest ecosystems,which may have provided sufficient K to microbes in our soil samples(already provided at the beginning of the incubation).However,at the present stage,we cannot conclude that K is not a limiting factor of soil microbial activity in other tropical forest ecosystems because of the heterogeneity of tropical forest ecosystems and few observations.The hypothesis needs to be tested in larger numbers of tropical forests.
文摘1 Introduction The Gremyachinskoye potassium salt field lies within the Safronovskaya area and is confined to the preoverthrust zone–the 20-25 kilometer band conventionally recognized in the southern termination of the Volga
