Abstract

NJANDJOCK NOUCK, Philippe et al. A geostatistical re-interpretation of gravity surveys in the Yagoua, Cameroon region. Geofís. Intl [online]. 2013, vol.52, n.4, pp.365-373. ISSN 2954-436X.

Since 1960, many gravity studies have been carried out in the Yagoua region of northern Cameroon. Gravity data was collected over a wide area of approximately 11628 km2. These data are insufficient, irregular, scattered and do not efficiently permit gravity field downward and upward continuations, derivatives and other operations that might require regular gridded data. Some anomalies on the Collignon map (1968), may correlate with known geological structure but do not appear on maps by Louis (1970) and Poudjom et al. (1996). To produce regular gridded gravity data and better control anomalies due to geological structures, the kriging method was applied to a 188-data baseline. Several variogram models were tested for this purpose. It was found that a spherical variogram model is the best; it has produced a new kriging dataset of about 10,100 data and a new map of kriged Bouguer data. This map contains positive anomalies in the Maroua-Mindif and Maga areas on the Collignon (1968) map, which were not present on Louis (1970) and Poudjom et al. (1996) maps. The positive anomalies of Guibi-Doukoula and Yagoua, not separated on the Louis (1970) and Poudjom et al. (1996) maps, show up as clearly distinct as previewed by Collignon (1968).The new results can be used for subsequent gravimetric studies.

Keywords : Bouguer anomaly; gravity data; geostatistics; variogram; kriging; Yagoua.

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