TRANSIENT FLUID-FLOW THROUGH THE TOE OF THE BARBADOS ACCRETIONARY COMPLEX - CONSTRAINTS FROM OCEAN DRILLING PROGRAM LEG 110 HEAT-FLOW STUDIES AND SIMPLE-MODELS

Thirty-four sediment and mud line temperatures were collected from six drill holes on Ocean Drilling Program (ODP) Leg 110 near the toe of the Barbados accretionary complex. When combined with thermal conductivity measurements from sediment cores and results from earlier surveys, these data delineate the complicated thermal structure on the edge of this convergent margin. Heat flow values at the seafloor of 92-192 mW m-2 are 80-300% higher than those predicted by standard heat flow versus age models for oceanic crust but are compatible with earlier seafloor measurements made in this area at the same latitude. Heat flow tends to decrease downhole at four sites, suggesting the presence of heat sources within the sediments. These results are consistent with the flow of warm fluids through the complex along high permeability conduits, including thrust faults, the major decollement zone, and sandy intervals. Simple calculations suggest that this fluid flow is transient, occurring on time scales of tens to tens of thousands of years. -from Authors