Colombia - The La Venta Konzentrat-Lagerstätte: a Neotropical moist forest biome of the middle Miocene

The very fossiliferous Neogene rock successions that outcrop in an emblematic ‘badlands’ landscape, located in the Upper Magdalena Valley (Department of Huila, Colombia), constitute an exceptional natural site with many undeniable attributes of universal value. These sedimentary rocks host one of the richest assemblages of fossil vertebrate fauna ever unearthed in South America and, constitute the main geological exposure of the site The La Venta Konzentrat-Lagerstätte: a Neotropical moist forest biome of the middle Miocene. The La Venta area extends from the eastern riverside of the Magdalena River, and topographically it constitutes a nearly flat terrain, gently westward inclined, with some small round hills. Its landscape is characterized by elongated escarpments, dipping slopes, and conspicuous gully systems, formed by almost continuously exposed and variegated bedrock. The absent or very limited development of regolith or of extensive soil over the bedrock and the presence of typical xerophytic vegetation confer to this region a remarkable ‘badlands’ scenery (Royo y Gómez, 1945; Fields, 1959; Villarroel et al., 1996; Guerrero, 1997; Montes et al., 2021). This landscape, known as the Tatacoa Desert, corresponds to an extensive tropical dry forest environment with the development of several distinctive ecosystems; and it has evolved through the interplay of lithology, long-term weathering, and the arid conditions induced by the orographic rain shadow of the Andean Mountain ranges (e. g. Garzón Massif), (Anderson et al., 2016; Dill et al., 2020; Montes et al., 2021).