The Case for Tectonic Control on Erosional Exhumation on the Tropical Northern Andes Based on Thermochronology Data

Abstract

Understanding how tectonic and climatic processes interact to control the rates and timing of exhumation of mountainous regions is critical for deciphering the underlying geodynamic mechanisms driving the movement of rock toward the surface and shaping earth's landscapes. Some empirical studies using

Peer Review #4 of "Synthesis of geological data and comparative phylogeography of lowland tetrapods suggests recent dispersal through lowland portals crossing the Eastern Andean Cordillera (v0.2)"

“…2, ~15-13 Ma), continued deformation caused widening of the EC (Mora et al, 2010), and the MA (Parnaud et al, 1995;Villamil, 1999;Bermúdez et al, 2010) isolating the Maracaibo Basin. At this time the deformation in the EC also began propagating southward (Saeid et al, 2017), beginning the isolation of the Magdalena Valley after ~13-11 Ma (Lundberg and Chernoff, 1992;Guerrero, 1997) with corresponding rock cooling as exhumation took place (Pérez-Consuegra et al, 2021). Fossil pollen and spores recovered in ~13 Ma old strata in western Amazonia suggest the presence of high Andean mountain forest in the northern Andes, perhaps as high as ~3 km (Hoorn et al, 2022).…”

Neogene variations in slab geometry drive topographic change and drainage reorganization in the Northern Andes of Colombia

“…South of the slab tear, where the Eastern Cordillera is narrower, the structural style changes to uplifted basement blocks, which are tilted monoclines of reduced width (Saeid et al, 2017). Also, the faults in this region record less displacement compared to faults north of the slab tear (Mora et al, 2008(Mora et al, , 2006Pérez-Consuegra et al, 2021;Saeid et al, 2017).…”

“…This could be reconciled if we consider that structural domains in the upper plate may not coincide exactly with the segmentation of the lower subducting plate. We hypothesize that the late Miocene plateau style of uplift within the Eastern Cordillera could be highly controlled by the areal extent and inherited structures of the former early Cretaceous rift (e.g., Mora et al, 2006;Pérez-Consuegra et al, 2021). The compression generated from below caused by the subducting plate could be located north of 5°N but the effects on uplift of the upper plate could reach more southerly regions even up to 4°N because that is the southern end of the early Cretaceous rift domain which would have behaved as a single tectonic province or coherent block (Carrillo et al, 2016;e.g., Mora et al, 2006;Pérez-Consuegra et al, 2021), which is probably analogous to the uplifted region of the northern Central Cordillera.…”

Cenozoic exhumation patterns in the northern Andes: Constraints from the southern Bucaramanga Fault, Eastern Cordillera, Colombia

“…A large part of these pre-existing discontinuities developed along the former passive margin of the South American plate and played an important role in the evolution of the orogen (Jacques, 2004;Mora et al, 2009). The distribution of thermochronological ages and the timetemperature history arising from these data have allowed the definition of tectonic blocks with different ages and cooling rates along the Eastern Cordillera (Shagam et al, 1984;Mora et al, 2008Mora et al, , 2013Mora et al, , 2015Parra et al, 2009;Amaya et al 2017;Pérez-Consuegra et al, 2021) and the Mérida Andes (Kohn et al, 1984;Bermúdez et al, 2010Bermúdez et al, , 2011van der Lelij et al, 2016a).…”