A New Architectural Element for Modelling the Neogene Fluvial Basins Impacted by Volcanism in Central Colombia (South America)
By implementing analysis of architectural elements into the sedimentologic description, we defined three deposition intervals associated with inter-eruptives and syn-eruptive periods for the volcaniclastic sequences. In the inter-eruptive periods, fluvial deposition in meandering and anastomosed streams associated with alluvial fan systems was developed, while the syn-eruptive periods were characterized by thick volcaniclastic deposition (up to ~150 m).
To determine the environments of deposition we applied Miall`s, architectural elements classification for the inter-eruptive periods. But, Miall's categorization was limited to define the sedimentation during the syn-eruptive periods. Therefore, we proposed a new architectural element, named SV, to define the catastrophic sediment flows formed during rapid deposition of pyroclastic and volcaniclastic events. These events abruptly overpassed the geomorphic threshold and altered the fluvial style conditions of the main drainage network in the fluvial basins.
This research project also intended to narrow the existing gap between the traditional sedimentology focused on the epiclastic deposits and the volcanology overwhelmed by the effusive and pyroclastic deposits. During the revision of the available bibliography related to the terminology for volcaniclastic sedimentation, we found the necessity for proposing an appropriate nomenclature to name volcaniclastic deposits due to the lack of lithofacies coding in the existent literature to describe these hybrid deposits.