International Center on Global scale Geochemistry

Langfang, China

International Center on Global scale Geochemistry

Langfang, China
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Zhang B.-M.,Chinese Academy of Geological Sciences | Zhang B.-M.,Key Laboratory of Geochemical Exploration | Zhang B.-M.,International Center on Global scale Geochemistry | Wang X.-Q.,Chinese Academy of Geological Sciences | And 9 more authors.
Geology in China | Year: 2016

In the past twenty years, more and more mineral deposits were discovered in basins. The traditional geochemical exploration methods are not effective in mineral exploration of conccalcd deposits in basins. Deep-penetrating geochemistry provides a new approach for exploration in basins. The case history studies from the concealed sandstone-Type uranium deposit hosted in a sedimentary basin, the concealed Ag-polymetallic deposit in a volcanic basin, the concealed Cu-Ni deposit in a basin covered by metamorphic rocks and the conccalcd Au deposit covered by loess have led the authors to reach the following conclusions: (1) Uranium is converted to uranyl ions [UO:]J∗ under the oxidizing condition and is easy to migrate under the influence of groundwater movement along sandstone pore structure and tectonic fissures; the uranyl ions arc absorbed on clay minerals after migrattion to earth's surface, because clay layers have a net negative charge, which needs to be balanced by interlayer cations; leaching of mobile forms of elements in soils and separation of fine-grained soils can be used to determine the orebodies; (2) The Yucyang Ag-polymetallic deposit was nearly formed in the same period as the volcanic rock; Ore-bearing fluid migrated to earth's surface along tectonic fissures in the formation process of the deposit; mobile forms of metals in ore-bearing fluid were absorbed on clay minerals; leaching of mobile forms of elements in soils and separation of fine-grained soils can be used to determine the orebodies in volcanic basins; anomalies of elements are directly displayed over the blind orebodies; (3) the contact zone between intrusive mass and metamorphic rock generated a lot of tectonic fissures in the proccss of emplacement of the ultrabasic intrusion; and the fluid would take ore-forming elements Cu and Ni and migrate to earth's surface and form cyclic anomaly; (4) ore-forming elements Au and Ag in the form of complexes, nano-scale elemental or alloy particles taken by fluid migrated upward in the ore- forming process of Au deposits in Luoning basin; compound or nanoparticles which dissociated from orebodies or rocks could penetrate loess pores and migrated upward to earth's surface and were absorbed on clay minerals; separation of fine-grained soils can be used to determine the orebodies. In this paper, the authors built deep-penetrating geochemical models for mineral deposits in basins based on application effects, anomaly shapes, characteristics of the covers, occurrences of the ore- forming elements, and migration patterns. The above results will provide theoretical and technical support for geochemical exploration in basins.


Wang X.-Q.,Chinese Academy of Geological Sciences | Wang X.-Q.,International Center on Global scale Geochemistry | Zhou J.,Chinese Academy of Geological Sciences | Zhou J.,International Center on Global scale Geochemistry | And 20 more authors.
Geology in China | Year: 2016

World- recognized harmonious gcochcmical baselines data are used to quantify environmental changes and mineral resources. The China Geochemical Baselines (CGB) project, as a part of Global Geochemical Baselines, was implemented from 2008-2014. The China Geochemical Baselines Networks with approximately 1600 reference grids cover the whole China. 6617 soil samples from 3382 drainage catchments were collected across China's whole mainland. 81 geochemical parameters including 78 chemical elements plus other 5 indicators were determined. China geochemical baselines data and maps were produced across the whole China. The baselines data and maps of 76 elements have correlation with geology, mineral resources, climate and human activities.


Wang J.-Y.,Henan Rock and Mineral Testing Center | Liu M.,Henan Rock and Mineral Testing Center | Zhao X.-L.,Henan Rock and Mineral Testing Center | Cao L.-F.,Henan Rock and Mineral Testing Center | Cao L.-F.,International Center on Global Scale Geochemistry
Yejin Fenxi/Metallurgical Analysis | Year: 2017

When phenylfluorone spectrophotometry is applied for the determination of Ta in ore sample, the coexisting elements such as Nb, Ti and Mo could also react with coloring agent, which had interference with the determination. The sample was decomposed with HF-HNO3-H2SO4 system. Nb was masked with oxalic acid, Ti was masked with H2O2, and Mo, Fe, V and Sn was reduced and masked with ascorbic acid and EDTA. The content of Ta was determined by phenylfluorone spectrophotometry with tartaric acid and cetyl trimethyl ammonium bromide as complexing agent in presence of surfactant polyvinyl alcohol. Consequently, the determination of Ta in ore sample was realized. The results showed that Beer's law was obeyed for mass concentration of Ta in range of 0.02-1.0 μg/mL. The linear correlation coefficient was 0.999 1, and the detection limit was 0.02 μg/mL. The proposed method was applied to the determination of Ta in three certified reference materials including lithium ore, tantalum ore and rare earth ore. The results were basically consistent with the certified values, and the relative standard deviations (RSD, n=10) were between 6.9% and 8.5%. The proposed method was suitable for the determination of Ta in batch ore samples in field. © 2017, CISRI Boyuan Publishing Co., Ltd. All right reserved.


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.


Wang X.,Chinese Academy of Geological Sciences | Wang X.,International Center on Global scale Geochemistry | Chi Q.,International Center on Global scale Geochemistry | Zhou J.,International Center on Global scale Geochemistry | And 22 more authors.
Journal of Geochemical Exploration | Year: 2015

The China Geochemical Baselines Project (CGB) was launched in 2008, and sampling was completed in 2012. Its purpose is to document the abundance and spatial distribution of chemical elements covering all of China. The database and accompanying element distribution maps represent a geochemical baseline against which future human-induced or natural chemical changes can be quantified. The sampling methodology was updated or developed for China's diverse landscape terrains of mountains, hills, plains, desert, grassland, loess and karst in order to obtain nationwide high-resolution and harmonious baseline data. Floodplain sediment or alluvial soil was used as the sample medium in plain and hilly landscape terrains of exorheic river systems in eastern China. Overbank sediment was adopted as the sampling medium in mountainous terrains of exorheic river systems in south-western China. Methods of collecting catchment basin and lake sediments were developed in desert and semi-desert terrains, respectively, in endorheic drainage systems in northern and north-western China. Two sampling sites were allocated to each CGB grid cell of 1° (long.)×40' (lat.), approximately equal to 80×80km in size. At each site, two samples were taken; one from a depth of 0-25cm and a second, deeper sample from a depth greater than 100cm or the deepest part of horizon C as possible as we can take. A total of 6617 samples from 3382 sites have been collected at 1500 CGB grid cells across the whole of China (9.6million km2), corresponding to a density of approximately one sample site per 3000km2. In addition, 11,943 rock samples have also been collected to aid in the interpretation of geogenic sources of elements. Before chemical analysis, the soil and sediment samples were sieved to <10mesh (2.0mm) and ground to <200mesh (74μm), rock samples were pulverised to <200mesh (74μm). Seventy-six chemical elements plus 5 additional chemical parameters of Fe2+, organic C, CO2, H2O+ and pH were determined under strict laboratory analytical quality control. An Internet-based software named Digital Geochemical Earth was developed for managing the database and maps. Initial results show excellent correlations of element distribution with lithology, mineral resources and mining activities, industry and urban activities, agriculture, and climate. © 2015 Elsevier B.V.


Wang X.,Chinese Academy of Geological Sciences | Wang X.,International Center on Global scale Geochemistry | Chi Q.,International Center on Global scale Geochemistry | Zhou J.,International Center on Global scale Geochemistry | And 22 more authors.
Journal of Geochemical Exploration | Year: 2015

The China Geochemical Baselines Project (CGB) was launched in 2008, and sampling was completed in 2012. Its purpose is to document the abundance and spatial distribution of chemical elements covering all of China. The database and accompanying element distribution maps represent a geochemical baseline against which future human-induced or natural chemical changes can be quantified. The sampling methodology was updated or developed for China's diverse landscape terrains of mountains, hills, plains, desert, grassland, loess and karst in order to obtain nationwide high-resolution and harmonious baseline data. Floodplain sediment or alluvial soil was used as the sample medium in plain and hilly landscape terrains of exorheic river systems in eastern China. Overbank sediment was adopted as the sampling medium in mountainous terrains of exorheic river systems in south-western China. Methods of collecting catchment basin and lake sediments were developed in desert and semi-desert terrains, respectively, in endorheic drainage systems in northern and north-western China. Two sampling sites were allocated to each CGB grid cell of 1° (long.)×40' (lat.), approximately equal to 80×80km in size. At each site, two samples were taken; one from a depth of 0-25cm and a second, deeper sample from a depth greater than 100cm or the deepest part of horizon C as possible as we can take. A total of 6617 samples from 3382 sites have been collected at 1500 CGB grid cells across the whole of China (9.6million km2), corresponding to a density of approximately one sample site per 3000km2. In addition, 11,943 rock samples have also been collected to aid in the interpretation of geogenic sources of elements. Before chemical analysis, the soil and sediment samples were sieved to <10mesh (2.0mm) and ground to <200mesh (74μm), rock samples were pulverised to <200mesh (74μm). Seventy-six chemical elements plus 5 additional chemical parameters of Fe2+, organic C, CO2, H2O+ and pH were determined under strict laboratory analytical quality control. An Internet-based software named Digital Geochemical Earth was developed for managing the database and maps. Initial results show excellent correlations of element distribution with lithology, mineral resources and mining activities, industry and urban activities, agriculture, and climate. © 2014 Elsevier B.V.

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