LATE PLIOCENE-PLEISTOCENE CLIMATE CHANGE FROM LA GUAJIRA PENINSULA (COLOMBIA)

The Guajira Peninsula physiography is comprised by a north vast land portion connected to the continent through a narrow bottleneck. Low lands are extended from the continent to the north part of the peninsula where are interrupted only by three major ranges -Macuira, Jarara and Cocinas-. This physiographic configuration makes its connection with the continent, susceptible to any important sea level fluctuation. Therefore, provenance analysis in sedimentary rocks will be a useful tool for identifying those fluctuations. Stratigraphic work in the Castilletes Formation shows major sea level oscillations by lithological and sedimentological changes. In this manner, it is possible to identify any major drop in the global sea level related to the onset of the northern hemisphere glaciation.

To understand the Guajira Peninsula desertification is important to consider the global and local context. As part of the local landscape there is the Macuira Range, the highest elevation in the Guajira Peninsula, with 864 meters over the sea level. Due to its localization, in the northernmost portion of the peninsula, and to its southeast-northwest trend, it constitutes an important physiographic barrier for the humid winds coming from the northeast to South America. As consequence, an amazing humid ecosystem has been developed in the Macuira Range. The impact of the Macuira Range is a shadow effect of humidity that could be responsible of the dominating dry climate conditions in the peninsula. Hence, the Macuira Range could be also responsible for the past drastic climate change that Castilletes Formation is showing. As a consequence ages of exhumation and desertification should be correlated. To address this possible explanation I plan to study the exhumation of the Macuira Range using thermochronology.

Invertebrate biostratigraphy, vertebrate paleontology, paleobotany and palynology studies are being conducted by paleontologist. Putting together their upcoming results with the stratigraphy, sedimentology, provenance, and thermochronology analyses will allow the better understanding of the dramatic ecological changes that took place during the last few millions years in the Guajira Peninsula.