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geochemical mapping:With Special Emphasis on Analytical Requirements

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Acta Geologica Sinica(English Edition) 2008年第2期82卷 451-462页

作者： XIE Xuejing CHENG Hangxin LIU Dawen Research Center of Applied Geochemistry Institute of Geophysical and Geochemical Exploration Chinese Academy of Geological Sciences Langfang Hebei 065000 Development and Research Center China Geological Survey Chinese Academy of Geological Sciences Langfang Hebei 065000

More than 40 national and regional geochemical mapping projects in the world carried out from 1973 to 1988 do not conform to common standards. In particular they have many analytical deficiencies. In the period 1988 to 1992, the International geochemical mapping project （Project 259 of UNESCO＇s IGCP Program） prepared recommendations designed to standardize geochemical mapping methods. The analytical requirements are an essential component of the overall recommendations. They included the following： 71 elements should be analyzed in future mapping projects; the detection limits of trace and ultratrace elements must be lower than the corresponding crustal abundances; and the Chinese GSD and Canadian STSD standard sample series should be used for the correlation of global data. A proposal was also made to collect 5000 composite samples, at very low sampling densities to cover the whole Earth＇s land surface. In 1997 an IUGS Working Group on Global geochemical Baselines was formed to continue the work which began with IGCP 259. From 1997 up to now, new progress has been made especially in China and FOREGS countries under the aegis of this working group, including the study of suitable sampling media, development of a multi-element analytical system, new proficiency test for selection of competent laboratories and role of wide-spaced mapping in mineral exploration. One of the major problems awaiting solution has been the inability of many laboratories to meet the IGCP recommendations to generate high quality geochemical maps. Fortunately several laboratories in China and Europe have demonstrated an ability to meet the requirements and they will be well placed to render technical assistance to other countries.

关键词： geochemical mapping geoanalysis analytical requirement extremely low density sampling

Gold enrichment characteristics and exploration prospects in Zambia: Based on 1∶1000000 geochemical mapping

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China Geology 2022年第1期5卷 60-70页

作者： Jun-ping Ren Jie Wang A-lei Gu Li-bo Zuo Hong-wei Sun Kang-kang Xu Fu-Qing He Chipilauka Mukofu Alphet Phaskani Dokowe Ezekiah Chikambwe Tianjin Center China Geological SurveyMinistry of Natural ResourcesTianjin 300170China Geological Survey Department of Zambia Lusaka P.O.Box.50135Zambia

The 1∶1000000 geochemical mapping of Zambia provides catchment sediment geochemical data for 58elements including Au from 746 sediment samples at 736 sampling sites,corresponding to a sampling density of about one site per 1000 *** strict quality control using field duplicates,certified reference materials,and analytical replicate samples,the Au was determined by Inductively Coupled Plasma Mass Spectrometry(ICP-MS).The detection limit of Au was 0.20×10^(-9).The 95%range(2.5%–97.5%)of Au concentrations was from 0.24×10^(-9) to 1.36×10^(-9),and the median value was 0.40×10^(-9).The most noticeable Au distribution patterns shown on the map are mainly located between Lusaka and Ndola(Lufilian Arc Belt).In addition,several high Au value areas occurred in Mansa,Muyombe,Chipata,and *** spatial distribution patterns of Au in tectonic units,drainage basins,and geomorphological landscapes could be related to the Lufilian Arc Belt and Bangweulu *** Au concentrations show metallogenic belts between Muyombe and Mbala areas,between Mansa and Ndola areas,and between Lusaka and Kasempa areas.

关键词： Gold geochemical mapping Enrichment characteristics Catchment sediment Metallogenic belt Mineral survey engineering Zambia

Digital Element Earth

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Acta Geologica Sinica(English Edition) 2011年第1期85卷 1-16页

作者： XIE Xuejing WANG Xueqiu CHENG Hangxin CHENG Zhizhong YAO Wensheng Institute of Geophysical and geochemical Exploration CAGS 84 Jinguang Road Langfang Hebei Province 065000 China

The resources and environmental problems are the two most fundamental issues facing all nations in the world. Everything in and on the Earth - minerals, animals and plants -is made from one, or generally some combination of, chemical elements, which are scientifically listed in the periodic table. Thus it is important to understand the present abundance and spatial distribution of all the elements across the Earth＇s surface. Such kinds of data can only be obtained at present and for the foreseeable future by on-earth geochemical mapping at all scales. The 30-year efforts made by Chinese geochemists in carrying out multi-element, multi-media, multi-scale geochemical mapping projects to delineate 39-76 element distribution at home and abroad culminated in a successful case of high- quality geochemical data acquirement. The new idea for a four-level plan for global geochemical mapping was advanced to obtain global data in the foreseeable future and the collection of updated geochemical information. Such information needs to be easily accessible not only by the science community, but also by industry, agriculture, governments, and even individuals, by all who would make an effort to promote sustainable riving on our planet. The concept of a Digital Element Earth （DEE） fulfills the aims.

关键词： Digital Element Earth chemical elements geochemical mapping sustainable development

Mineral resource analysis by parabolic fractals

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Mining Science and Technology 2009年第1期19卷 91-96页

作者： XIE Shu-yun YANG Yong-guo BAO Zheng-yu KE Xian-zhong LILT Xiao-long State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan Hubei 430074 China Faculty of Earth Science China University of Geosciences Wuhan Hubei 430074 China Department of Geography York University Toronto ON M3J1P3 Canada School of Resources and Earth Sciences China University of Mining ＆ Technology Xuzhou Jiangsu 221116 China

Elemental concentration distributions in space have been analyzed using different approaches. These analyses are of great significance for the quantitative characterization of various kinds of distribution patterns. Fractal and multi-fractal methods have been extensively applied to this topic. Traditionally, approximately linear-fractal laws have been regarded as useful tools for characterizing the self-similarities of element concentrations. But, in nature, it is not always easy to find perfect linear fractal laws. In this paper the parabolic fractal model is used. First a two dimensional multiplicative multi-fractal cascade model is used to study the concentration patterns. The results show the parabolic fractal （PF） properties of the concentrations and the validity of non-linear fractal analysis. By dividing the studied area into four sub-areas it was possible to show that each part follows a non-linear parabolic fractal law and that the dispersion within each part varies. The ratio of the polynomial coefficients of the fitted parabolic curves can reflect, to some degree, the relative concentration and dispersal distribution patterns. This can provide new insight into the ore-forming potential in space. The parabofic fractal evaluations of ore-forming potential for the four suhareas are in good agreement with field investigation work and geochemical mapping results based on analysis of the original data.

关键词： parabolic fractal multiplicative multifractal cascade modeling ore-forming potential geochemical mapping

Siltstone geochemical Compositions: Applications for Event Size and Correlation

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International Journal of Geosciences 2016年第2期7卷 189-199页

作者： Kannipa Motanated Michael M. Tice The Department of Geological Sciences Chiang Mai University Chiang Mai Thailand The Department of Geology and Geophysics Texas A&M University Texas USA

Thinly laminated siltstone and sandy siltstone are major components of the Upper Permian Brushy Canyon Formation, west Texas and south New Mexico. These rocks have been variously interpreted as the deposits of low-density turbidity currents or as windblown sediment deposited over water. Nevertheless, all models agreed that this lithology was deposited without subsequent reworking by bottom currents or burrowing organisms. These siltstones, thus, are ideal test units for quantitatively estimating hydraulic properties of the flows that formed them. In particular, the Zr/Ti ratio was tested as a geochemical proxy for flow size and transport distance. In situ geochemical abundance and grain size of particles with contrasting susceptibility to erosion—Zr- and Ti-rich particles—were mapped and measured by X-ray fluorescence analytical microscopy, μXRF. Lamination thickness was measured from Fe fluorescence intensity, which increased sharply at the top of each layer. Within the same sample, zircon grains were systematically finer than rutilated quartz grains. Zr/Ti fluorescence ratio positively correlated with lamination thickness, not particle sizes. In other words, Zr/Ti fluorescence ratio fluctuations resulted from variations in mineral abundance. Therefore, variations of Zr/Ti fluorescence ratio in these siltstones are likely caused by fluctuations in the intensity of erosional events rather than transport distance. High Zr/Ti ratios and thick laminations reflect periods of enhanced erosion. The average wind velocity during typical events was estimated to be at least 150 km?hr?1, or the equivalent of a Category 1 hurricane. The method used here could be applied to both outcrop and subsurface strata correlation.

关键词： Windblown Dust Laminated Siltstones geochemical mapping Upper Permian Brushy Canyon Formation