Resumo

PARDO, NATALIA; CEPEDA, HÉCTOR  e  JARAMILLO, JOSÉ MARÍA. THE PAIPA VOLCANO, EASTERN CORDILLERA OF COLOMBIA , SOUTH AMERICA : VOLCANIC STRATIGRAPHY . Earth Sci. Res. J. [online]. 2005, vol.9, n.1, pp.3-18. ISSN 1794-6190.

We recognized a Quaternary volcano in the Eastern Cordillera of Colombia between longitudes 73º9'4”W to 73º3'39”W and latitudes 5º40'28”N to 5º45'20” N. Paipa volcano has an eroded edifi ce that reaches 300 m above the Cundiboyacense high-plateau (2871 m.s.l), and a 3 Km caldera with several vents inside it. Volcanic products overlay sedimentary rocks of Upper Cretaceous age and cover a 31 Km2 area. Geologic fi eld mapping, stratigraphy and petrography analysis has been made to establish eruptive units and pyroclastic transport and deposition processes in order to reconstruct volcanic activity history. Caldera outfl ow facies are ash fall deposits and ash and pumice fl ow tuffs interbedded with fl uvial and torrential deposits. There are also several geothermal springs including CO2 vents northward the caldera. The infl ow facies are lava-domes, ash and block fl ow tuffs and pyroclastic surge deposits interbedded with fl uvial and lacustrine deposits. We defi ned 14 eruptive units within two eruptive epochs: the fi rst one comprises the formation of a volcanic caldera and its collapse, while caldera resurgence took place during the second epoch. Single events ages are not well known because of lack of radiometric dating; 1.9 to 2.5 Ma K/Ar and Ar/Ar ages suggest a Pliocene and Pleistocene range for Paipa volcanism.

Palavras-chave : caldera; eruption unit; ignimbrite; domes; magmatic eruption; phreatomagmátic eruption; pyroclastic flow; pyroclastic surge.

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