The Plio-Quaternary Magdalena Turbidite System

Abstract

The Magdalena Turbidite System (MTS) is the second largest modern turbidite system of the South American subcontinent, however little is known about its stratigraphic architecture. It develops on the Caribbean Margin of Colombia, in the area of oblique convergence between the South American and the Caribbean tectonic plates. Major fan development occurred after the Miocene. During the Plio-Quaternary the MTS development is characterized by three main periods of sedimentary evolution: i) Pliocene-Early Pleistocene; ii) Early-Late Pleistocene; and iii) Holocene. During Pliocene-Early Pleistocene (i) the fan construction was predominantly controlled by mass-flows, a broad drainage network of erosive turbidity channels and apron deposits. The generalized instability of the margin obeys to a period of intense tectonic activity (Andean orogeny). During Early-Late Pleistocene (ii) fan construction resulted from the lateral switching of fan depocenters and margin tectonics affected the position of the Magdalena River with consequent formation of several canyon-channel systems along the margin. Finally, during the Holocene (iii) fan construction is restricted to the continental slope. The Magdalena River shifted till the present-day position where the continental shelf is practically inexistent. The new delta progrades onto the continental slope where several canyons develop and cut the deformational front.