Petrogenesis of a meso-cenozoic arc from the central cordillera of the Colombian Andes: implications on the crustal growth of the northern Andes

Abstract

The nature of the I type magmatism in the northern Andes, especially in Colombia has been scarcely studied in terms of its petrogenesis and only a few geochronological data is known. Its implications for the subduction evolution of the western margin of northern South America are still the focus of intense debate.It is known by researchers that the Northern Andes from Ecuador to Colombia include a series of typical magmatic arc rocks, which have been originated after the breakup of Pangea and such arcs are still active today. The complexity of these magmatic arcs bears on its origin related to the interaction of the Pacific, Caribbean and South American plates. This scenario is suitable to cause changes in the subduction conditions that modify the type of magma, the conditions in the sources, and allow the recycling of supracrustal material. This complex magmatic history can be studied in the Central Cordillera of the Colombian Andes, where outcrop a series of meso-Cenozoic granitic rocks, and these magmatic bodies are close together and were added to the chain during three periods: Jurassic (Ibague Batholith), Cretaceous (Mariquita Stock) and Eocene (Hatillo Stock). To understand the dynamics of formation of the chain, we plan to study the evolution of these bodies through methods such as isotope geochemistry and U-Pb and Hf in zircon. The different methods combined provide elements for understanding the geodynamic evolution of the orogenic chain of the Colombian Andes, with general implications related to crustal growth in the Northern Andes and the identification of magmatic pulses from various sources related to the dynamics of subduction zones. (AU)