Heat flow of the eastern Canadian rifted continental margin revisited

Continental shelves are regions where heat flow is not measured directly by conventional marine techniques, but estimated from oil exploration data with possible bias. In order to overcome this problem, we recently proposed a method based on neural networks (Geophys J Int 2006, 166:115) that provides better constraints on thermal conductivity: it allowed us to derive 161 heat flow estimates on the eastern margin of Canada, where previous studies had concluded to the existence of heat flow higher than that in the adjacent continent and ocean. We conversely found rather homogeneous values (similar to 45-55 mW m(-2)) all along and across the margins, from Labrador to Nova Scotia. The difference seems essentially related to the porosity of sediments that was not taken into account in previous studies. Our results support a high asymmetry for the conjugate Iberian-Canadian margins, and could indicate that mantle heat flow increases abruptly from the Canadian shield to the margins.