Entity

Time filter

Source Type


Liu X.,Chinese Academy of Geological Sciences | Liu X.,Key Laboratory of Geochemical Exploration | Wang X.,Chinese Academy of Geological Sciences | Wang X.,Key Laboratory of Geochemical Exploration | And 2 more authors.
Journal of Geochemical Exploration | Year: 2015

Catchment/floodplain sediment geochemical datasets from three continental-scale geochemical projects in Australia (AU), China (CH) and Europe (EU) were studied by comparing sample media, sample preparation, elements determined, analytical methods, detection limits and proportions of reportable values, and certified reference materials used. Twenty six elements (Ba, Ce, Co, Cr, Cu, Mo, Nb, Ni, Pb, Rb, Sr, Th, V, Y, Zn, Zr, Al2O3, CaO, K2O, MgO, MnO, Na2O, P2O5, SiO2, Fe2O3 (total), TiO2) were considered comparable among the 35 determined by all three projects, according to the criteria for global comparability of elements proposed in this paper. The median concentrations of all elements (except Co, Y, Zr, SiO2 and TiO2) in the three datasets increase in the following order: AU Source


Liu X.,Chinese Academy of Geological Sciences | Liu X.,Key Laboratory of Geochemical Exploration | Wang X.,Chinese Academy of Geological Sciences | Wang X.,Key Laboratory of Geochemical Exploration
Earth Science Frontiers | Year: 2014

The spatial distributions and changes of elements in the earth have been studied by global-scale geochemical mapping, providing basic datasets and maps for the sustainable development of resources and environment. This paper briefly describes the history of global-scale geochemical mapping, and gives an evaluation and comparison for the sampling and analytical programs of the six global-scale mapping projects conducted in the past 20 years in China, Europe, North America and Australia. Among these mapping projects only European FORGES project collected multi-media samples (soils, stream sediments, floodplain sediments, humus, stream water); the China Geochemical Baselines project collected samples from different geomorphic landscapes (soils in agricultural plain land, floodplain/overbank sediments in mountainous terrains, catchment sediments in desert terrains); and the other four projects (Australia NGSA, USA NASGLP, Chinese EGMON, European GEMAS) using uni-media sampling program, collected soil or floodplain/catchment sediments. The analytical methodology in China reaches international leading level: 78 elements can be determined; their detection limits meet the requirements for global-scale geochemical mapping; and the analytical quality is controlled by standard reference materials. Source


Liu X.,Chinese Academy of Geological Sciences | Liu X.,Key Laboratory of Geochemical Exploration | Wang X.,Chinese Academy of Geological Sciences | Wang X.,Key Laboratory of Geochemical Exploration | And 2 more authors.
Journal of Geochemical Exploration | Year: 2015

Catchment/floodplain sediment geochemical datasets from three continental-scale geochemical projects in Australia (AU), China (CH) and Europe (EU) were studied by comparing sample media, sample preparation, elements determined, analytical methods, detection limits and proportions of reportable values, and certified reference materials used. Twenty six elements (Ba, Ce, Co, Cr, Cu, Mo, Nb, Ni, Pb, Rb, Sr, Th, V, Y, Zn, Zr, Al2O3, CaO, K2O, MgO, MnO, Na2O, P2O5, SiO2, Fe2O3 (total), TiO2) were considered comparable among the 35 determined by all three projects, according to the criteria for global comparability of elements proposed in this paper. The median concentrations of all elements (except Co, Y, Zr, SiO2 and TiO2) in the three datasets increase in the following order: AU2O, MgO and Zn are generally greater than 2 (and up to 7), which could be explained partly by protracted weathering in Australia, and partly by the smaller grain size fraction analysed of the CH dataset (<1mm) compared to AU and EU (<2mm). In conclusion, a unified sample medium should be collected and unified sample preparation techniques should be followed. Key elements related to mineral resources and the environment should be determined and international or exchanged internal standard materials inserted in new national or global geochemical mapping projects in order to generate globally comparable datasets for establishing global geochemical baselines. © 2013 Elsevier B.V. Source


Yao W.,Chinese Academy of Geological Sciences | Yao W.,Key Laboratory of Geochemical Exploration | Xie X.,Chinese Academy of Geological Sciences | Xie X.,Key Laboratory of Geochemical Exploration | And 3 more authors.
Journal of Geochemical Exploration | Year: 2014

Systematic mapping of nearly all elements in the periodic table to cover the entire earth's surface is still a dream for the applied geochemists in the world. Chinese geochemists have been active in the implementation of Global Geochemical Mapping Program. In the past thirty years, a series of systematic geochemical mapping programs have been conducted in China. These programs have greatly contributed to the development of the concept and methodology for the Global Geochemical Mapping Programs, such as the proper sampling medium selection, analytical scheme development, reference material development and also for the establishment of the quality control system. Based on the new sampling concept and encouraging results obtained from the representative experiments conducted in China, a new outline for the Global Geochemical Mapping Program is forwarded. © 2013 Elsevier B.V. Source


Wang X.,Chinese Academy of Geological Sciences | Wang X.,Key Laboratory of Geochemical Exploration | Wang X.,International Center on Global scale Geochemistry | Liu X.,Chinese Academy of Geological Sciences | And 19 more authors.
Journal of Geochemical Exploration | Year: 2015

The China Geochemical Baselines (CGB) project provides nation-wide catchment sediment/alluvial soil geochemical baseline data for 76 elements including Hg from 3382 top (0-25cm) and 3380 deep sediment/alluvial soil samples (under a depth of 100cm) at 3382 sampling sites, corresponding to a sampling density of about 1 site per 3000km2. Mercury was determined by cold vapour generation atomic fluorescence spectrometry (AFS) under strict quality control using field duplicates, standard reference materials and analytical replicate samples. The 25th percentile is at 13 and 11μg/kg in top and deep sediment/alluvial soil samples, respectively; these concentrations are close to the crustal abundance in China. The median Hg value is at 26 and 18μg/kg in top and deep sediment/alluvial soil samples, respectively; the 75th percentile is 56μg/kg in top and 36μg/kg in deep sediment/alluvial soil samples. Mercury concentrations at the 50th (26μgHg/kg) and 75th (56μgHg/kg) percentiles exhibit systematic enrichment in the near-surface material. The Hg distribution maps show distinct increasing trends from northern to southern and from western to eastern China, which are primarily related to the distribution of parent rocks, including rocks associated with mineral resources of Hg, Sb, Au, As, Pb-Zn, and climate, resulting in different soil types, as well as to population density with accompanying industrial development. Anomalous Hg concentrations in top sediment/alluvial soil samples above the 85th percentile (87μg/kg) occur mainly in south and south-west and sparsely in north and east China; they most likely have a dual origin, natural and human-induced, with the latter having a greater contribution because of the intense industrial activities, and particularly mercury emissions from Hg, Sb, As, Au, Pb-Zn mining, coal combustion, and production of batteries, fluorescent lamps, thermometers and cement. The spatial distribution map of Hg ratios of top to deep sediment/alluvial soil samples displays higher values, suggesting that top samples are most likely polluted from human activities in the highly populated urban areas of eastern China. About 6.86% and 3.52% of top and deep sediment/alluvial soil samples, respectively, have Hg concentrations higher than the soil contamination limit of 150μg/kg set by the National Environmental Standards for Heavy Metals of the People's Republic of China. © 2015 Elsevier B.V. Source

Discover hidden collaborations