1 Introduction Halunwusu Composite Granites,locates in the northern margin of Belt,between the North Qaidam block and the Central Qilian block,with two phases of magmatic activities.The granites mainly consisits of th...1 Introduction Halunwusu Composite Granites,locates in the northern margin of Belt,between the North Qaidam block and the Central Qilian block,with two phases of magmatic activities.The granites mainly consisits of the Early展开更多
Air pollution has become an important issue,especially in Caribbean urban areas,and,particulate matter(PM)emitted by different natural and anthropogenic sources causes environmental and health issues.In this work,we s...Air pollution has become an important issue,especially in Caribbean urban areas,and,particulate matter(PM)emitted by different natural and anthropogenic sources causes environmental and health issues.In this work,we studied the concentrations of PM_(10) and PM_(2.5) sources in an industrial and port urban area in the Caribbean region of Colombia.PM samples were collected within 48-h periods between April and October 2018 by using a Partisol 2000 i-D sampler.Elemental geochemical characterization was performed by X-ray fluorescence(XRF)analysis.Further,ionic species and black carbon(BC)were quantified by ion chromatography and reflectance spectroscopy,respectively.Using the Positive Matrix Factorization(PMF)receptor model,the contributions of PM sources were quantified.The average concentration of PM_(10) was 46.6±16.2μg/m^(3),with high concentrations of Cl and Ca.For PM_(2.5),the average concentration was 12.0±3.2μg/m^(3),and the most abundant components were BC,S,and Cl.The receptor model identified five sources for PM_(10) and PM_(2.5).For both fractions,the contributions of marine sea spray,re-suspended soil,and vehicular traffic were observed.In addition,PM_(2.5) included two mixed sources were found to be fuel oil combustion with fertilizer industry emissions,and secondary aerosol sources with building construction emissions.Further,PM_(10) was found to also include building construction emissions with re-suspended soil,and metallurgical industry emissions.These obtained geochemical atmospheric results are important for the implementation of strategies for the continuous improvement of the air quality of the Caribbean region.展开更多
From a large number of case studies on terrestrial deposits we know that Late Holocene climate fluctuations have an important impact on the terrestrial environments. However, it is hitherto not clear how the marine se...From a large number of case studies on terrestrial deposits we know that Late Holocene climate fluctuations have an important impact on the terrestrial environments. However, it is hitherto not clear how the marine sediments can be used to shed light on the environment and climate change of the catchment. To provide such insight, we used the major element, trace element and rare earth element(REE) compositions in the southern Yellow Sea(SYS) sediments to reconstruct the changes in weathering and erosion of their source regions. The sediments originate predominantly from the upper crust of East China and are transported into the basin especially by the Yellow River(Huanghe) and to a lesser extent by the Yangtze River(Changjiang). The chemical index of alteration(CIA; 53.7–59.7) suggests low chemical weathering of the source rocks since the Middle Holocene. This is consistent with the relatively cool and arid climate in North China after the Holocene Megathermal. Comparison of element ratios, including Al/Ca, K/Ca, Al/Na, K/Na, Rb/Sr, Li/Ba and the CIA shows that we can use the latter as a robust proxy for climate change. The CIA-based mean annual precipitation and mean annual temperature show a series of climate fluctuations in the catchment. A relatively warm and humid Period I(5.3–2.9 cal. ka BP), a relatively cool and dry Period II(2.9–0.9 cal. ka BP) and an increasingly cool and dry Period III(0.9–0.3 cal. ka BP). These periods can be linked to climate intervals recognized elsewhere.展开更多
基金supported by the China Geological Survey(grants 1212011086065,12120113033004,121201010000150014-40)the Research Fund for the Doctoral Program of Higher Education of China(grant 20125122110010)
文摘1 Introduction Halunwusu Composite Granites,locates in the northern margin of Belt,between the North Qaidam block and the Central Qilian block,with two phases of magmatic activities.The granites mainly consisits of the Early
基金financial support from the Departamento Administrativo de CienciaTecnología e Innovación(Colciencias)for Project#141180764164,Contract 815-2018。
文摘Air pollution has become an important issue,especially in Caribbean urban areas,and,particulate matter(PM)emitted by different natural and anthropogenic sources causes environmental and health issues.In this work,we studied the concentrations of PM_(10) and PM_(2.5) sources in an industrial and port urban area in the Caribbean region of Colombia.PM samples were collected within 48-h periods between April and October 2018 by using a Partisol 2000 i-D sampler.Elemental geochemical characterization was performed by X-ray fluorescence(XRF)analysis.Further,ionic species and black carbon(BC)were quantified by ion chromatography and reflectance spectroscopy,respectively.Using the Positive Matrix Factorization(PMF)receptor model,the contributions of PM sources were quantified.The average concentration of PM_(10) was 46.6±16.2μg/m^(3),with high concentrations of Cl and Ca.For PM_(2.5),the average concentration was 12.0±3.2μg/m^(3),and the most abundant components were BC,S,and Cl.The receptor model identified five sources for PM_(10) and PM_(2.5).For both fractions,the contributions of marine sea spray,re-suspended soil,and vehicular traffic were observed.In addition,PM_(2.5) included two mixed sources were found to be fuel oil combustion with fertilizer industry emissions,and secondary aerosol sources with building construction emissions.Further,PM_(10) was found to also include building construction emissions with re-suspended soil,and metallurgical industry emissions.These obtained geochemical atmospheric results are important for the implementation of strategies for the continuous improvement of the air quality of the Caribbean region.
基金funded by the"Strategic Priority Research Program"of Chinese Academy of Sciences(Nos.XDA11020102 and XDA05030402)the National Natural Science Foundation of China(No.41376090)+2 种基金the Research Fund for the Doctoral Program of Higher Education of China(No.20120145120017)the Marine Safeguard Project(No.GZH201200503)the Special Fund for Basic Scientific Research of Central Colleges,China University of Geosciences Wuhan
文摘From a large number of case studies on terrestrial deposits we know that Late Holocene climate fluctuations have an important impact on the terrestrial environments. However, it is hitherto not clear how the marine sediments can be used to shed light on the environment and climate change of the catchment. To provide such insight, we used the major element, trace element and rare earth element(REE) compositions in the southern Yellow Sea(SYS) sediments to reconstruct the changes in weathering and erosion of their source regions. The sediments originate predominantly from the upper crust of East China and are transported into the basin especially by the Yellow River(Huanghe) and to a lesser extent by the Yangtze River(Changjiang). The chemical index of alteration(CIA; 53.7–59.7) suggests low chemical weathering of the source rocks since the Middle Holocene. This is consistent with the relatively cool and arid climate in North China after the Holocene Megathermal. Comparison of element ratios, including Al/Ca, K/Ca, Al/Na, K/Na, Rb/Sr, Li/Ba and the CIA shows that we can use the latter as a robust proxy for climate change. The CIA-based mean annual precipitation and mean annual temperature show a series of climate fluctuations in the catchment. A relatively warm and humid Period I(5.3–2.9 cal. ka BP), a relatively cool and dry Period II(2.9–0.9 cal. ka BP) and an increasingly cool and dry Period III(0.9–0.3 cal. ka BP). These periods can be linked to climate intervals recognized elsewhere.