Stratigraphy of a middle Miocene neotropical Lagerstätte (La Venta Site, Colombia)

The middle Miocene Konzentrat-Lagerstätte of the La Venta site recorded in the Honda Group contains invaluable information on the biotic response to the climatic changes of the Miocene Climatic Transition. Its fossil record has been studied for almost a century and offers one of the best windows to the Neotropics terrestrial ecosystems during the Neogene. We have compiled all published studies and, using graphic correlation and a recently published geological map for the region, placed them into a composite standard section. Furthermore, we improved its chronostratigraphic control by analyzing new geochronological data (U-Pb in zircons) and developing a probabilistic age model using a Bayesian framework. The results suggest that most of the fossil assemblage of the Honda Group accumulated in a meandriform fluvial system (upper part of La Victoria Formation – lower part of Villavieja Formation) that later shifted to an anastomosed system (upper part of Villavieja Formation). The c. 552-m-thick La Victoria Formation is younger than 16 Ma and older than 12.58 Ma, whereas the c. 569-m-thick Villavieja Formation is younger than 12.58 Ma and older than 10.52 Ma. The La Venta site is crucial for understanding Miocene paleoecological dynamics in northern South America, but despite decades of studies, it is still in the early phase of exploration.