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In 1918, the geologist Emile Grosse was commissioned to conduct geological studies in the Amagá Basin, Antioquia, Colombia. In 1923, Grosse finished a comprehensive cartographic work that became the cornerstone for the geology of the northwest (NW) Colombian Andes. Today, 100 years later, the volcanoclastic strata preserved in the Amagá Basin are crucial for understanding major Oligocene to Pliocene tectonic events that occurred in the NW South-American margin, including the fragmentation of the Nazca Plate, the collision of the Panamá-Chocó Block, and the shallowing of the subducted slab. Our contribution includes new mineral chemistry and zircon petrochronological data from the Combia Volcanic Complex and published data to provide a review of the Oligocene to Pliocene deformation, sedimentation, and magmatic patterns in the Amagá Basin and their implications for the tectonic evolution of NW South America. The Amagá Basin was the result of the Eocene to Oligocene uplift of the Western Cordillera followed by the Middle Miocene to Pliocene uplift of both the Central and Western cordilleras, events that modified the Miocene drainage network in the Northern Andes. Coeval with the final Miocene deformation phases in the Amagá basin, the magmatism of the Combia Complex was the result of subduction magmas emplaced in a continental crust affected by strike-slip tectonics.
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This content will become publicly available on March 1, 2026
The Role of Transpressional Tectonics, Volcanism, and Fluvial Processes on the Oligocene to Pliocene Evolution of Intermontane Basins of the Western Colombian Andes
Abstract We use new and published detrital zircon U‐Pb data (n > 10,000) from Oligocene‐Pliocene strata of intermontane basins of the western Colombian Andes and surrounding regions to study the evolution of sedimentary systems during the transition from arc collision/accretion to subduction. Our database indicates a shift from a compartmentalized basin architecture, locally fed by transverse drainages, toward one with enhanced connectivity and longitudinal sediment dispersal during the Middle‐Late Miocene. These events were accompanied by the end of local marine influence on depocenters and the progressive uplift of the flanking Colombian Cordilleras as they became continuous topographic features. Post‐Pliocene local and transient disruption of longitudinal rivers was caused by damming and valley‐filling, attributed to volcaniclastic flows. We interpret the inherent segmentation of strike‐slip faults and their morphological expressions as the primary controls on depocenter evolution during Early‐Middle Miocene arc collision/accretion. The subsequent transition to subduction and the tectonic segmentation of the continental margin triggered asymmetrical basin inversion in the western Colombian Andes. The modern rugged morphology in the northern intermontane region is arguably associated with widespread uplift due to upper plate cooling and strengthening by shallow subduction of the Coiba microplate. Conversely, the wide and flat morphology of aggradational basins in the southern intermontane area is interpreted as the result of incomplete inversion and the dominance of strike‐slip tectonics. The “normal” subduction of the Malpelo microplate beneath southern Colombia might be linked to a higher heat flow and localized deformation in the intra‐ and back‐arc regions.
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- Award ID(s):
- 1925939
- PAR ID:
- 10635213
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Tectonics
- Volume:
- 44
- Issue:
- 3
- ISSN:
- 0278-7407
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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