Diego Felipe Vallejo Hincapié

D. Jaramillo, M. I. Vélez, R. Trejos, A. Pardo and V. Vargas, Instituto de Investigaciones en Estratigrafía (IIES)-Univ. de Caldas, Manizales-Colombia [diego.vallejo@ucaldas.edu.co]

The lacustrine sedimentary record of the Zarzal Formation: a complex interaction between tectonic, climatic, and volcanic influence during the post-Pliocene in Western Colombia

The Zarzal Formation is located in the northern part of the Andean ranges of Colombia, between Western and Central Cordilleras. At this site, siltstone, mudstone, and volcanic rocks known as Zarzal Formation are filling the Cauca valley basin. This depression was formed at least during the last Tertiary tectonic event in the Colombian Andes. Remote sensing analyses, sedimentology, stratigraphy and diatoms assemblages suggest that this unit was deposited in a lacustrine environment. The origin of this paleolake would have been related with damming episodes of one of the most important rivers in Colombia, the Cauca River. In accordance with soft-sediment deformation structures and volcano-sedimentary deposits, this lake was affected by tectonic and volcanic events, which probably were also related with the damming of the Cauca River. In addition, siliceous microfossils records show changes in the level of water and chemical composition of this lake. Our preliminary results reveal that the Zarzal Formation is a key deposit to understand the interaction between climatic, tectonic, and volcanic mechanisms during the post-Tertiary period.