Arctic geothermal structures inferred from Curie-point depths and their geodynamic implications

Abstract

We applied the modified centroid method with a fractal magnetization model on a new magnetic anomaly grid for the Circum-Arctic area (CAMP) to obtain the first high-resolution Arctic Curie-point model and to infer geothermal structure. The shallowest Curie-point depths, found in the oceanic domain, reveal the cooling pattern of oceanic lithosphere and asymmetric mantle thermal activities across spreading ridges. The Cretaceous High Arctic large igneous province (HALIP), the most prominent magmatic feature in the Arctic, shows slightly lower heat flow and higher thermal conductivities than the surrounding area, indicating a complete cooling of the HALIP, but HALIP also has shallow Curie-point depths. We attribute this contradiction to the high titanium content of HALIP that lowers the Curie temperature. Therefore, Curie-point depths constrain well the boundary of the HALIP. On the Arctic continental shelves, the largest Curie-point depths are found in deep sedimentary basins, where lower crust eclogitization was previously interpreted. Furthermore, we found that this positive correlation between large Curie-point depths and large sediment thickness is prevalent for global continental margin sedimentary basins.