Abstract

VARGAS, Carlos A et al. NEW GEOLOGICAL AND GEOPHYSICAL CONTRIBUTIONS IN THE SECTION IBAGUÉ - ARMENIA , CENTRAL CORDILLERA - COLOMBIA . Earth Sci. Res. J. [online]. 2005, vol.9, n.2, pp.99-109. ISSN 1794-6190.

Based on geophysical and structural observations a geologic section between the cities of Ibagué and Armenia ( Colombia ) has been interpreted to establish the dominant structural style and the basement configuration at depth. Gravimetric and magnetic measurement were initially taken each 500 m along these cities, which helped in the development of the “Armenian-Quake” seismic experiment. The experiment illuminated reflectors down to approximately 17 km deep in an influence area of approximately 25 km. The complete interpretation of the geological and geophysical information allows concluding that the Cajamarca complex defines a wide synclinal near to Cajamarca town. With this information initially it was possible to recognize the presence of a basement compound for wedges of basaltic and sedimentary rocks associated to the Quebradagrande and Arquía formations. Then was recognized the existence of a great flexion of the oceanic paleo -plate related to the Barroso formation, which is limited at west by the Cauca-Almaguer fault. The flexion structure and the evolution of the stress in this region of South America could be responsible for the deposit and later folding of the “ Cinta de Piedra formation” that constitutes the Santa Bárbara range .

Keywords : Armenia-Quake; seismic active experiment; geophysical modelling; serpentinites; earthquakes.

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