The Distal Orinoco Turbidite System: Morpho-Sedimentary Characteristics and Implications for the Dynamics of Gravity Flows and Bottom Currents

Ercilla, G, B. Alonso, J. Baraza, D. Casas, F. Estrada, F. Perez-Belzuz, and M. Farran

Abstract

The distal part of the Orinoco turbidite system (from 4,500 to 5,000 m waterdepth) has been surveyed with state-of-art, high-resolution acoustic techniques such as the SIMRAD EM12 multibeam and the SIMRAD-TOPAS ultra-high-resolution parametric echo sounders. New results indicate that the Orinoco turbidite system shows at least two active systems of sediment transfer, towards the north and towards the east. Both sediment transfer systems depict a great morpho-sedimentary complexity in which braided channels, variable sinuosity channels and distal depositional lobes coexist even in short distances. Such a morpho-sedimentary complexity is the result of different patterns of sediment transport of the gravity flows within the turbidite system, and then of different styles of sedimentation. In addition, the conmplexity of the East-trending sediment transport system is accentuated by the activity of bottom currents or unchannelized turbidity currents whose interaction with the topography generates a sediment wave field on the southern inner margin of the turbidite system.