Discovering the Fascinating Geology of Colombia: 750 Ma Recorded in Rocks, Volcanoes, and Mineral Resources.

28th of Jan - 10th of Feb 2024

Mme María M. Ariza Acero, UNIL M. Corin Jorgenson , UNIGE M. Rocio Jaimes Gutierrez, UNIGE Mme Carolina Díaz Vecino, UNIGE M. Iván Mateo Espinel Pachon, UNIGE M. Francisco Muñoz Burbano, UN

Dr. Lucia Dominguez, UNIGE (Stage 2) Dr. Richard Spikings, UNIGE (Stage 3) Dr. Pedro Patarroyo, Colombian (Stage 1) Dr. Marta Calvache or Dr. John Londoño - Geological survey of Colombia (Stage 2) Juan Carlos Molano (Stage 3) Andrés Rodríguez (Stage

*** Deadline for registration is THE 1ST OF DECEMBER 2023 ***

Colombia, located in the northwestern corner of South America, represents a unique tectonic environment that preserves the record of the breakup of Rodinia, the assembly and disassembly of Gondwana, and the long-lived evolution of an active margin under hyper-extension, with significant growth of new continental crust (a hot subject) during its Caribbean interaction. The interplay between the Caribbean and the Nazca Oceanic Plate subducting under the South American plate makes, therefore, the geological setting of Colombia quite diverse and distinctive, where rocks spanning from the Paleoproterozoic to the Holocene are outcropping as a result of the complex deformation of the Northern Andes, sub-divided in three Cordilleras. This field trip proposes a journey through the sedimentology, volcanology and ore mineralogy on this corner of the Earth. The drainage of the largest rivers of Colombia shaped the landscape of the Andes Cordilleras, and contrasts with the deformation promoted by the accretionary prisms and the prominent uplifting of the Sierra Nevada de Santa Marta in the Caribbean region. With 14 Holocene volcanoes distributed from the south-west to central Colombia, active volcanism represents a significant threat to at least 5 million people living within 30 km of active volcanoes. Indeed, the 1985- Nevado del Ruíz eruption is the 4th most lethal event in the historical record with ~23.000 fatalities. Finally, the Guyana Craton in the east preserves the most ancient rocks of the Northwestern corner of South America where the main source of the nowadays sedimentary rocks is located. We propose a field trip to Colombia aiming to bring together a detailed review of the evolution of the regional geology through time, to understand the associated geological processes, by posing the following questions, that among others can be the seeds for future research: 1) How do active margins evolve over periods of 100 Ma and more?; 2) How is the new continental crust built in this specific tectonic environment?; 3) How do active margins respond to the interaction with the heterogeneous (different densities, thickness, composition) oceanic lithosphere?; 4) What are the implications and past lessons of living in an active and highly populated volcanic region?; 5) What are the processes that favored the concentration of mineral resources, particularly in porphyry systems?; 6) Why does Colombia have a vast record of the Cretacic units in the Easter Cordillera? On-site and hands-on recognition of the geology of Colombia represents an exceptional opportunity for PhD students and researchers of multiple disciplines to better understand the dynamics of this unique site of the Earth, and to comprehend its implications in terms of hazards and resources. The local and Swiss universities researchers together with the participants configure a great synergy to promote a detailed revision of the regional geology, a fructiferous scientific discussion, and why not the beginning of near-future multi-disciplinary collaborations. SEDIMENTOLOGY We propose to study the tectono-stratigraphic evolution of the Andes, and its implications for hydrocarbon reservoirs through field observations of the central tectonic domain of Colombia (ANH, 2007). This region is delimited to the east by the Eastern Cordillera and to the west by the Central Cordillera, extending to the Romeral fault system. The stratigraphy in the Eastern Cordillera of the Villeta formation, consists in Albian to Campanian mudstones. This formation, originally presumed to be deposited in a passive margin setting, has been shown (Jaimes and Freitas, 2006) to have a more complex tectonic history. VOLCANOLOGY Active volcanism is concentrated in the Central Cordillera of Colombia resulting from the subduction of the Nazca plate beneath the South American plate. This region is a source of knowledge about volcanic processes from multiple perspectives such as petrology, physical volcanology, volcano-monitoring, and risk management. In particular the Northern volcanism including the Nevado del Ruíz, Cerro Machín, and Cerro Bravo expose remaining features of multiple eruptive styles and their footprint on the territory. This will be an extraordinary opportunity to understand the processes of an active system and the potential impacts over the surrounding region. ORE MINERALOGY While many of the easily accessible ore deposits have already been discovered, the real challenge for both industry and geologists worldwide lies in uncovering these concealed deposits that lie deep beneath the surface. This requires innovative exploration techniques, advanced remote sensing technologies, and sophisticated data analysis methods to detect subtle geological signatures and anomalies that are indicative of hidden mineralization. Mineral exploration in Colombia presents exceptional challenges. Unlike regions with more exposed geological features, such as barren deserts or rocky terrains, Colombia's deposits seem to be deep seated with small surface exposure. Marmato gold-mining is a discovery under particular conditions. From one side, this region stands as an exceptional setting to: i) comprehensively study porphyry systems, ii) investigate ore metal zoning patterns and complex alteration processes, iii) get acquainted of advanced exploration techniques and efficient extraction processes, and iv) delve into the depths of igneous petrology and high/low-temperature mineralization processes. On the other hand, the visit allows to unravel the intricate genetic links and potential telescoping phenomena within a single locality. Indeed, the mine in question represents a distinctive case study where national and international regulations attempt to couple with local societal conce

Colombia

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