Abstract

BAYONA, Germán. The onset of the mountain uplift in the northern Andes: A perspective based on Coniacian to Paleocene tectono-sedimentary studies. Rev. acad. colomb. cienc. exact. fis. nat. [online]. 2018, vol.42, n.165, pp.364-378. ISSN 0370-3908.  https://doi.org/10.18257/raccefyn.632.

Several mountain belts in the northern Andes are the source of sediments transported to adjacent oceans by extensive fluvial systems, but this present configuration does not correspond to the initial stages of the Andes growth. The integration of sedimentological, stratigraphic, geochronological and data provenance from the Coniancian to Paleocene strata exposed to the east of the Central Cordillera allow interpreting how depositional systems changed from marine to continental settings, and establishing the location of the first mountain belts and drainage systems that supplied terrigenous sediments into the basin. The onset of the emergence of blocks above a pre-existing middle-Cretaceous marine platform began in the early Campanian time to the west and in the late Campanian to the east, increasing the supply of terrigenous detrital sediments to the marginal and marine depositional systems. In the Maastrichtian to Paleocene time, several eastern intrabasinal uplifts and the western marginal mountain belt grew to the north, associated with the collision of allochthonous blocks along the northwestern corner of South America. Together with the growth of mountain belts, new drainage systems began to form and run into basins with high subsidence rates. Fluvial systems covered continental and marginal plains, but the low capacity of sediment transportation in these basins favored the accumulation of coarse terrigenous fragments in channels, floodplains, and inland deltas, whereas only muddy sediments arrived at the shoreline. This uplift evolution of mountain belts and drainage systems differ from previous studies that suggest the onset of intraplate deformation since the Paleocene time.

Keywords : Northern Andes; Uplift; Sedimentology; Campanian; Maastrichtian; Paleocene.

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