Abstract
While bedforms are increasingly being recognized and analyzed in bathymetric and seismic data sets, exact mechanisms for the formation of large bedforms are not well understood. This paper describes a suite of Paleocene to Miocene bedforms found along a series of contourite terraces that compose the Uruguayan continental slope. Results are compared with similar bedforms found along other continental margins. This study describes diagnostic, large-scale features associated with major discontinuities, including channels, scours, furrows, sand ribbons, and barchan dunes. These record periods of increased bottom current activity and thus represent distinct paleoceanographic markers within the basin. Sequences of layered, muddy two-dimensional dune-like bedforms also commonly occur between discontinuities. The vertical bedform distribution exhibits a repetitive pattern generated by bottom currents, with sediment supply from simultaneous downslope processes deposited primarily over discontinuous intervals. Sediment reworking and redistribution along slope by bottom currents generated thick, extensive sand-rich deposits concentrated at particular locations. These features raise fundamental questions concerning margin processes, morphologies, stratigraphic context, and bedform development in deep-marine environments. Given their role in paleoceanographic reconstructions and resource exploration, these deposits and the mechanisms that form them require more formal understanding.
