In response to the performance of the Global Goochomical Sampling (a subproject of the IGCP Project 259, International Geochemical Mapping), an orientation study was conducted in 1989-1990 to develop an optimum wide-spaced geoehemical sampling approach in Jiangxi Province, Southsart China. 121 overbank sediment samples were collected in an area of about 157,000 km2, with the average sampling density being 1 sample/1,300 km2, and the sampling coverage being 24%. Most of the samples were collected at outflow sites of the drainage basins with an area of 100-500 km2, including 33 samples that control basins of 400-2,000 km2.Overbank sediment samples were taken at a dspth of 50-120 cm, and the samples were analyzed quantitatively for 38 elements. The representativeness of wide-spaced overbot sediment sampling is discussed from vinous angles in the paper, with tho following conclusions reached:-Sampling at the outflow areas of 400-2,000 km2 drainage basins can reveal the major minoralizations in the basins;-W, Sn, Cu. Pb and Zn in both wide-spaced samples and drainage sediment samples collected at a density of a samples/km2 manifest similar regional geochemical trends;-Distribution of W, Pb, Be and Rb coincides with the Yanshanian graftes closely related to the major ore-forming plocesses in Jiangxi;-Distribution of "3Ni +Cr + V" in wide-spaced samples can distinctly reveal the boundary between the Yangtze paraplatform and the Caledonian fold symbol in Jiangxi.
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［2］ 江西省物化探大队,江西省区域地球物理·地球化学场的基本特征-1:50万物化探图件说明书,1985.
［3］ Bogen, J., BoIviken, B. and Ottesen, R. T., EnvironmentaI studies in Western Europe using overbank sediment. In: Erosion and Sediment Transport Monitoring Programme in River Basins (Proceeding of the Oslo Symposium, August, 1992).IAHS Publ. no. 210. pp. 317-325.1992.
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［5］ Ottesen, R. T., Boaeo, J., Bolviken, B. and Volden, T., Oierbank sedimcnt,a representative sample medium for regional geochemieal mapping. J. Geochem. Explor., 32: 257-277, 1989.
［6］ Plant, J. A., Hale, M. and Ridgway, L, Developments in regional geochemistry for minesal ezplora-lion.Trans. Inst. Min. Metall., Sect. B. Appl. earth sci., B110-B140,1988.
［7］ Plant, J. A., Breward,N.,Simpson, P. R·and Slater, D., Regional geochemistry and the identifica-lion of metallogenic pro}inces;examples from lead-zinc-barium, tin-uranium and gold deposits. In:A. G. Darnley and R. G. Garrett (Editors),International Geochemieal Mapping. J. Geochem. Ezplor.,39:195-224, 1990.
［8］ Xie Xuejing, Some problems, strategical and tactical, in international geochemical mapping. In:A. G.Darnlcy and R. G.Garrett (Editors), International Geochemieal Mapping. J. Geochem. Explor., 39:15-33,1990.
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