MORPHOLOGY AND INTERNAL ARCHITECTURE OF A CHANGING CONTINENTAL SHELF: GULF OF MORROSQUILLO

Acquisition of 50 bathymetry and high resolution profiles (echosounder transducers of 200 and 12 Khz respectively) collected under the EAFIT-COLCIENCIAS project "Geomorphology of the shallow shelf of Departamento de Cordoba and Golfo de Morrosquillo" allowed mapping the morphology and stratigraphic architecture of the inner shelf (depths < 10 m) seafloor and sub-seafloor under Gulf of Morrosquillo. The morphology of the inner shelf, as depicted on a bathymetry map based on 200 kHz soundings, appears broadly as a concave up, largely erosive surface that reaches the 10 m isobath at distances of 2 and 3.5 km from the shoreline. At several localized sites (such as in the NE of the study area), echosounder data provide evidence of positive terrain anomalies, apparently corresponding to recent mud volcanoes of well preserved tops tens of meters across, or recently faulted. The 12 kHz records, which offer a vertical resolution of 30 to 80 cm, were able to penetrate 5 m below the seafloor at various places, and allowed recognition of several buried erosional and depositional features including scarps, angular unconformities, and filled paleochannels. These seafloor and subseafloor features are evidence of an extremely active Holocene dynamics, with important eustatic and tectonic components.