Taken from Preface to the Geochemical Atlas of Eastern Bolivia.
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 geology and mineral potential of the whole of the project area are summarised in:
Litherland M et al. 1986. The geology and mineral resources of the Bolivian Precambrian. British Geological Survey Overseas Memoir No. 9, BGS Keyworth, Nottingham, UK
The results of the regional geochemical survey are presented in:
Appleton J D and Llanos A. 1985. Geochemical Atlas of Eastern Bolivia. British Geological Survey, Keyworth, Nottingham, UK.
These results are presented 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. This combination of maps permits the identification of regional related to major variations of bedrock composition as well as single or clusters of anomalously high values that may be indicative of mineralisation.