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Gravimetric study of a potential mineral deposit in the Itapororoca region, Brazil

2008; Wiley; Volume: 56; Issue: 5 Linguagem: Inglês

10.1111/j.1365-2478.2008.00696.x

1365-2478

Marta Sílvia Maria Mantovani, Wladimir Shukowsky, Benjamim Bley de Brito Neves, André Rugenski,

Geochemistry and Geologic Mapping

ABSTRACT A semi‐detailed gravity survey was carried out over an area of 650 km 2 localized in the Eo‐Neoproterozoic coastal zone of Paraiba State where 548 new gravity stations were added to the existing database. Gravity measurements were made with a LaCoste and Romberg model G meter with a precision of 0.04 mGal. The altitude was determined by barometric levelling with a fixed base achieving a 1.2 m measure of uncertainty, corresponding to an overall accuracy of 0.24 mGal for the Bouguer anomaly. The residual Bouguer map for a 7th degree regional polynomial showed a circumscribed negative anomaly coincident with a localized aero‐magnetic anomaly and with hydro‐thermally altered outcrops, near the city of Itapororoca. The 3D gravity modelling, constrained by geologic mapping was interpreted as a low density, fractured and/or altered material with a most probable volume of approximately 23 km 3 , extending to about 8,500 m depth. This result is in accordance with a volcanic body associated with hydrothermal processes accompanied by surface mineralization evidence, which may be of interest to the mining industry.