stripes
This is a ring structure identified in 1971 by side-scanning radar and lying close to large northwest-trending fractures. It comprises an oval ring some 10 km in diameter and forming a depression open to the west, and a central ridge of 6x2 km running north-south. The area is dense rain forest with a very thick lateritic cover extending to at least 200 m depth. Off the ridge the rocks of the ring are principally tonalites, granodiorites and granites which show some signs of fenitization. Eight boreholes along the ridge down to 200 m remained in laterite but fragments from the bottom part of some holes, although partially weathered, are identifiable as fenites; some baryte occurs. Quartz rocks pseudomorphing carbonate crystals are also present and these rocks have traces of Th, Zn and REE. Trace element work on laterites indicates high values for Ba, Nb, REE and Th and it is concluded that deep weathering of a carbonatite is involved.
- H.M. Aarden, personal communication, 1981.
- AARDEN, H.M., AROZENA, J.M.I. de, MOTICSKA, P., NAVARRO, J.G., PASQUALI, J.Z. and SIFONTES, R.S.G. 1973. El complejo geologico del area del Impacto Distrito Cedeno Estado Bolivar, Venezuela. Internal Report, Ministerio de Minas e Hidrocarburos, Direccion de Geologia, 53 pp.
- GARCIA, V. and AARDEN, H.M. 1977. Analisais preliminar de correlaciones y agrupaciones geo-quimicas en lateritas del Cerro Impacto, Estado Bolivar. Memoria, V Congreso Geologico Venezolano, Caracas - Ministerio de Energia y Minas. Sociedad Venezolana de Geologos, 3: 941-55