On the geology of the southern part of the Macarena

Authors

  • Fernando Paba Silva Servicio Geológico Nacional
  • Thomas van der Hammen Servicio Geológico Nacional

DOI:

https://doi.org/10.32685/0120-1425/bolgeol6.1-3.1958.285

Keywords:

Bauxite, layer, diamonds, cross stratification, Guayabero formation, plateaus

How to Cite

Paba Silva, F., & van der Hammen, T. (1958). On the geology of the southern part of the Macarena. Boletín Geológico, 6(1-3), 4–30. https://doi.org/10.32685/0120-1425/bolgeol6.1-3.1958.285

Issue

Section

Articles

Published

1958-01-01

Abstract

The Sierra de La Macarena is located between latitudes 2° 10' and 3° 20' and longitudes 73° 40' and 74° 05' West of Greenwich. Sediments cover its southern part from the Recent to Upper Cretaceous age. Pebbles, conglomerates, and sandstones with cross-stratification, shales, and quartzite sandstones predominate with a general gentle dip to the East ranging between 3° and 4°. The presence of Siphogenerinoides clarki in the jasper pebbles confirms its Maastrichtian - Campanian age, as well as the finding of some pollen association in the shales of the Losada Formation, speak in favor of the Paleocene. Once the correlation of the La Macarena Formation with the Roraima Formation is proven, there is the possibility of finding economically exploitable diamonds in the pans and terraces of the rivers and streams that descend from La Macarena without violating its status as a national reserve.

An extensive area is covered by a pisolitic bauxite deposit up to 73% A12O3, veiled by a layer of iron oxide (limonite) about 0.6 m thick, with an iron content (Fe2O3) of 51.44%.

References

GANSSER, A. 1954.-"The Guiana Shield (S. América)". Eclogae Geol. Helvet., Vol. 47, l.

HAMMEN, TH. van der. 1958.-"Estratigrafía del Terciario y del Maestrichtiano y Tectogénesis de los Andes Colombianos". Inf. 1279.

HURLEY, P. M., 1958.-"Variations in isotopic abundances of Strontium, Calcium and Argon and related topics". Sixth annual progress report for 1958, U. S. Atomic Energy Commission.

Me. CoNNELL, R. B. 1969.-The Takutu Formation in British Guiana, and the probable age of the Roraima Formation. Second Carib. Geol. Conf., Puerto Rico.

TRUMPY, D., 1943.-"Pre Cretaceous of Colombia". Bull. Geol. Soc. Amer., Vol. 54.

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