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A collection of regional geochemical data, mainly from stream sediment surveys, gathered from many BGS overseas projects since 1960s. Some areas are well covered and well documented with data available digitally on CD-ROM. Projects from 1960s and 1970s generally have no digital data and information exists only in paper form.
Regional Geochemical data from drainage basin reconnaissance survey carried out as part of a bilateral aid project between the UK Department for International development (DFID) (formerly ODA) and the Indonesian Government. Some 23,000 stream sediment samples collected and analysed (less than 80 mesh fraction) for Copper, Lead, Zinc, Cobalt, Nickel, Manganese, Silver, Arsenic, Molybdenum, Tin and Tungsten (partial extraction) and Lithium, Potassium, Chromium and Iron (total extraction). Samples collected and classified on the basis of 1:250 000 map quadrangle areas. Data gathering completed in two phases: First phase: North of the equator (North Sumatra Project, NSP). Second phase: South of the equator (Southern Sumatra Geological and mineral exploration Project). Sampling and analytical methodology has been consistent throughout. All data is available as on the Sumatra CD-database CD-ROM. North of the equator data published as 1:250 000 single element classified symbol plots and as a monochrome geochemical atlas. South of the equator data published as 1:250 000 single element proportional symbol plots and a geochemical atlas (hardcopy and CD-ROM). Projects also involved regional geological mapping and in Southern Sumatra regional geophysics (gravity). Raw data can be obtained from the Directorate of Mineral Resources, Bandung, Indonesia.
During the period 1967 to 1971 a team of geoscientists carried out a programme of regional geological mapping in parts of Peru and a low-density regional geochemical exploration survey of the Western Cordillera of northern Peru. The work was funded by the UK Overseas Development Administration (ODA - now the Department for International Development, DfID) in collaboration with the Servicio de Geologia y Mineria (SGM), Lima, Peru (now INGEMMET). The geochemical exploration project was managed by a BGS geologist/ geochemist and supported by counterpart staff from the SGM. Locational and analytical data, maps and interpretative unpublished reports were deposited at the SGM in Lima in 1971. The geochemical data are a long term asset and continued interest in the results, particularly in recent years, has required that the data be made more readily available in a digital format. Some 1345 sites were sampled and stream sediments were analysed for Cu, Pb, Zn, (Co), Ag, Mo, (As), and (V). Raw data can be obtained from INGEMMET, AV Canada, 1470, San Borja, Lima, PERU. The sample location data have been digitised from a sample site map, as the original field sample cards and the port-a-punch cards were not retrievable in 1998/99. The sample site map was a paper copy - so, although the UTM co-ordinates for locations are given to the nearest metre, the true location of the original sample sites may vary by as much as 500 m, or in some cases even more. GENP 1967-71 was a low-density regional exploration survey based on the collection of some 1260 samples at key sites within the 25,000 km2 project area - a density of approximately 1 sample per 20 km2. Data cleaned for absent and below detection limit values.
Two geochemical surveys were undertaken in the Solomon Islands between 1976 and 1983 as part of a combined geological mapping and mineral exploration project. The survey of Choiseul and the Shortland Islands was carried out between 1976 and 1979 by the Institute of Geological Sciences (now the British Geological Survey) with support from staff of the Geology Division of the Ministry of Land, Energy and Natural Resources, Solomon Islands. The project produced 12 geological maps at 1:50,000 scale as well as a series of unpublished reports. The survey of the New Georgia Group of islands was undertaken between 1979 and 1983. The project produced 7 geological maps at a scale of 1:100,000 and a regional map of the entire island group at a scale of 1:250,000. A series of multielement geochemical anomaly maps were produced at a scale of 1:100,000 to accompany each of the published geological maps. Master copies of these are held at the Geological Survey in Honiara. Full descriptions of the methods used are described in the margins of the anomaly maps. A total of 8848 stream sediment samples were collected from Choiseul and 7441 from the New Georgia Group, resulting in an average sampling density for the two areas of 2.68 samples per km2 and 1.47 samples per km2 respectively. Sampling in the Shortland Islands was confined to the larger islands, 187 were collected from the Fauro Island group, 148 from Alu and 69 from Mono. The samples were dry sieved and the fraction passing -80 mesh B.S. (177 microns) was analysed. A hot concentrated nitric acid digestion was used prior to analysis by atomic absorbtion spectrophotometry (AAS) for Co, Cu, Pb, Zn, Ni, Ag, and Mn. Samples from the vicinity of the Siruka Ultramafic Complex were determined for Cr by AAS after digestion by a bisulphate fusion technique. Raw data can be obtained from the Geology Division, Ministry of Mines and Energy, PO Box G37, Honiara, Solomon Islands.
During the period 1982-86 a team of geologists from the British Geological Survey carried out a programme of regional geological mapping and geochemical exploration in collaboration with the Zimbabwe Geological Survey under a Technical Co-operation agreement supported by the UK Department for International Development (DFID) (formerly Overseas Development Agency). Three regions of Zimbabwe were mapped (Harare, Rushinga & Nyampanda, and Makaha) and the results of the stream sediment geochemical surveys were presented as three reports. Over 17,000 stream sediments were collected and analysed for Cu, Pb, Zn, Co, Ni, Mn, Li, As, Ba, Sn, Ta, and W. Raw data can be obtained from the Geological Survey of Zimbabwe, PO Box CY210,Causeway, Harare, Zimbabwe.
Between 1976 and 1982, the Overseas Directorate of the British Geological Survey, United Kingdom and the Geological Survey of Bolivia, Santa Cruz, carried out a major reconnaissance geological mapping, geochemical sampling and mineral exploration programme of that part of the Precambrian Brazilian Shield lying within eastern Bolivia. Previous geological work had been undertaken in the area, but this was the first time that a systematic and fully integrated survey had been attempted. The Project area is approximately 220,000 square kilometres and regional geochemical samples were collected from 8185 sites producing an overall sampling density of 1 sample per 27 square kilometres. Because of logistic problems it was impossible to sample certain inaccessible areas so the actual sampling density was 1 sample per 16 square kilometres for the 130,000 square kilometres effectively sampled. The geochemical samples were analysed in the Project laboratories in Santa Cruz and in the GEOBOL geochemical laboratories in La Paz. Uranium analyses were carried out by a commercial laboratory in the UK. The results of the Project are incorporated in 21 comprehensive reports in both English and Spanish. Twelve describe the geology, geochemistry and mineral potential of the individual 1:250,000 map areas and the remainder are devoted to the geology and mineral potential of areas of special geological or economic interest. The stream sediments were determined for: Ag, Co, Cu, Fe, Mn, Ni, Pb, Zn, As, U, B, Ba, Be, Cr, La, Li, Mo, Nb, Sn, Sr, Y, and Zr. These results are presented in an atlas as 22 single element 1:1 million scale, classed proportional symbol, point source data maps in which the symbols are overprinted on a simplified geological base map in order to facilitate rapid data interpretation. A 1:4 million scale moving average map based on a 4 x 4 km cell size and a 10 km search radius, printed alongside the symbol map, identifies the major regional variations. Raw data is available from the Geological Survey of Bolivia, Santa Cruz along with copies of the reports.