Active margin structures within the North slope of the Muertos trench

Abstract

Seismic reflection records from the north slope (landward slope) of the Muertos Trench south of Hispaniola reveal features similar to those seen on reflection records from Pacific active margins. Tectonically rotated sediment ponds characterize the slope; landward-dipping reflection horizons within the wedge of sediments underlying the slope suggest possible fault planes. Oceanic crust can be traced landward of the trench axis for tens of kilometers beneath the sediment wedge. Seismic refraction velocities are similar to velocity profiles found in Pacific inner trench slopes. The above similarities between the Muertos Trench inner slope and the inner slopes of Pacific trenches suggest similarities in tectonic origins. Although the Muertos Trench, unlike Pacific trenches, is not associated with a belt of active volcanism or a well-defined Benioff zone, models that explain the structure of Pacific trench inner slopes in terms of imbricate thrusting may also apply to the north slope of the Muertos Trench.