- 1Agencia Estatal Consejo Superior de Investigaciones Científicas (CN IGME CSIC), MADRID, Spain (fm.rubio@igme.es)
- 2Agencia Estatal Consejo Superior de Investigaciones Científicas (CN IGME CSIC), MADRID, Spain (e.merino@igme.es)
Gravity study of the Giraúl pegmatitic field (Namibe province, SW Angola)
José Luis García-Lobón1*, Carmen Rey-Moral1, Enrique Merino-Martínez2, Ezequiel Ferreira1, Félix Rubio1
1 IGME-CSIC. c/ La Calera 1. 28760 Tres Cantos. Madrid. *Corresponding author: jl.garcia@igme.es
2 IGME-CSIC. c/ Ríos Rosas, 23. 08003. Madrid.
Abstract
The Giraúl Pegmatitic Field (Namibe province, Angola) contains hundreds of pegmatite bodies, including several enriched in Li, Be, B, Cs, Rb, Sn and Ta, occurring in a corridor oriented in a WNW-ESE direction and covering an area of more than 150 km2. The pegmatites intruded into the Palaeoproterozoic Namibe Group metasediments and diverse basic to ultrabasic intrusions (gabbros, diorites, and sparse pyroxenites) scattered throughout the area. This study focuses on the gravity survey of the Muvero and Lepamby prospects of the Giraúl field, which contain Li-enriched pegmatites and are currently being explored by private companies. Between 2023-2024, 346 gravimetric stations were measured at the prospects along N-S and E-W profiles using the CG-6 Autograv™ gravimeter and the Pentax G-7 GPS system. Standard gravity data corrections were applied and an adequate reduction density was used, estimated by correlation between Bouguer anomalies and topography. The results obtained are consistent with the presence of interstratified amphibolites in the Namibe Group, along with some intrusions of dense basic to ultrabasic bodies, which create a clear density contrast with respect to the lighter pegmatites. Relative gravity minima are observed in the Bouguer anomaly map, related to pegmatitic structures. The integrated geointerpretation of surface geological information and in-depth 2.5D gravity models indicate the presence of pegmatitic bodies at depths up to 250 m. Furthermore, a number of unsuspected pegmatitic zones have been revealed. These results are very promising for future exploration of pegmatites and associated minerals in the Giraúl pegmatitic field.
How to cite: García-Lobón, J. L., Rey-Moral, C., Merino-Martínez, E., Ferreira, E., and Rubio, F.: Gravity study of the Giraúl pegmatitic field (Namibe province, SW Angola), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7907, https://doi.org/10.5194/egusphere-egu25-7907, 2025.
