A significant geological discovery in the La Cascabel ravine, within the Baraya municipality of Huila, Colombia, has revealed evidence of a shallow sea that existed approximately 470 million years ago during the Ordovician period. This ancient marine environment, shaped by tidal currents, offers a profound glimpse into Colombia's geological past and its deep-rooted connection to the supercontinent Gondwana.
The research, led by geologist Carlos Ernesto Rodríguez of the National University of Colombia, involved extensive fieldwork in Baraya, including the collection and analysis of 41 rock samples. Petrographic microscopy and X-ray diffraction confirmed that tidal processes were the dominant force shaping the layered rock deposits of the Venado Formation. This geological unit dates back to the Ordovician period (485 to 444 million years ago), an era known for its warm, shallow seas teeming with marine invertebrates like trilobites and brachiopods.
The precise dating of these ancient sediments was achieved through the identification of microfossils, specifically acritarchs such as Adorfia hoffmanensis and Coryphidium bohemicum. These microscopic marine organisms, believed to be the cysts of planktonic algae, are crucial for stratigraphy and helped pinpoint the deposits to the upper Floian-Dapingian stages. This finding resolves a long-standing question about the Venado Formation's timeline.
Rodríguez's findings also indicated that these rocks experienced temperatures nearing 200°C, which altered their mineral composition but preserved their sedimentary features. This preservation allowed scientists to distinguish the Venado Formation from other geological units in Colombia that had been previously misclassified as metamorphic. While the Venado Formation may not have immediate economic value, its scientific importance is immense, contributing significantly to the global understanding of the Paleozoic era and filling a critical gap in Colombia's geological map.
The discovery paints a vivid picture of a Huila vastly different from today's landscape, instead revealing a realm of shallow seas alive with primitive marine creatures. This groundbreaking research, supported by the National University and the local community, not only expands scientific knowledge but also fosters a deeper connection to the land for local communities, offering a unique perspective on Huila's ancient heritage. The study opens doors for further investigations in other parts of Huila and Colombia, promising more revelations about our planet's deep history.