Late Miocene – Pliocene eastward magmatic arc migration record in the Northern Andes at 5°N latitude, west-central Colombia

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ABSTRACT Volcanic stratigraphy provides major insights to understand the spatial and temporal relationships between volcanic products and eruptive and post-eruptive processes. In the Andean chain, the Neogene to modern magmatic arc front has shown major changes in their spatial and compositional characteristics, which have been commonly related to significant modifications in the plate configuration. In the northern segment of the Colombian Andes, at 5°N latitude, a series of Upper Miocene-Pliocene volcanic and volcaniclastic units record the Neogene tectono-magmatic evolution associated with the formation of the Andean orogen. Stratigraphic observations allow recognising primary, secondary, and non-volcanic products that document intra- and inter-eruptive episodes characterised by Plinian eruption styles associated with the construction of volcanic edifices, followed by inter- and post-eruptive periods with significant fluvial dominated sedimentation. This indicates the reworking of volcanic products associated with the destruction and the collapse phase of volcanic edifices. New geochronological data (U-Pb and K-Ar) and several published ages suggest the existence of a continuous arc magmatism from the Miocene until the present, with major changes in its spatial position of the frontal arc: during the Late Miocene (~6 Ma), was exposed in the west between the Middle Cauca Valley to the Central Cordillera, while during the Pliocene (~4 Ma), it was located exclusively in the Central Cordillera. This configuration was the result of the inland magmatic arc migration associated with the subduction dynamics of the Nazca plate (Malpelo microplate) under the South American margin that also promoted a late phase of exhumation of the Cordillera.