Resumo

GARCIA GONZALEZ, Mario; MIER UMANA, Ricardo  e  CRUZ GUEVARA, Luis Enrique. PALEOTHERMAL HISTORY RECOSTRUCTION OF THE BAJA GUAJIRA SUB-BASIN, COLOMBIA. bol.geol. [online]. 2010, vol.32, n.2, pp.55-71. ISSN 0120-0283.

The paleothermal history of the Coger Guajira Sub-basin was achieved using three methods: 1) calculation of the presents geothermal gradient and heat flow, 2) vitrinite reflectance and, 3) fission track analysis on apatites and zircon grains. New analytical data of vitrinite reflectance and fission tracks allowed identifying four termal events with the following features: The oldest termal event took place during the Late Cretaceous between 95 and 65 Ma. The second termal event occurred during the late Eocene between 40 and 35 Ma. The third termal event occurred in the Early and Middle Miocene between 22 and 15 Ma. The fourth and last termal event took place in the Late Miocene between 10 and 5 Ma. The cooling events match with four unconformities previously identified: 1) the Late cretaceous unconformity at the top of the Guaralamai Formation, 2) The Late Eocene unconformity at the base of the Siamana Formation, 3) The Early to Middle Miocene unconformity on the top of the Siamana Formation, and 4) The Late Miocene unconformity on the top of the Castilletes Formation.

Palavras-chave : Guajira Basin; Paleothermal history; Vitrinite reflectance; Apatite and zircon fission tracks.

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