GEOL 5903 Seminar: Gabriel Sombini dos Santos
28 November, 2016
Geol 5903 Seminar: Gabriel Sombini dos Santos
Title: Contrasting Earth's thermal history models and their geologic implications.
Location: Huggins Science Hall, Room 336, 12:30 p.m.
Abstract:
Earth’s thermal history is a controversial topic in geosciences. An adequate understanding of the topic is of paramount importance, as the Earth’s heat loss provides the energy that drives plate tectonics and all related processes. Based on advances in boundary layer theory and the recognition that the Earth’s mantle is convective, several parametric thermal history models were proposed in the late 1970s and early 1980s. These models, however, could not reconcile the low abundance of heat production elements in the mantle, constrained by geochemistry and cosmochemistry, with the theoretical requirements of the physics of thermal convection. These parametric models required high concentration of heat-producing elements in the mantle, with lower values resulting in unrealistically high temperatures, in what was termed thermal catastrophe. This issue remained unresolved for decades. Based on analysis of the physics of subduction zones, a new thermal history model compatible with the low abundance of heat-producing elements in the mantle emerged. This model does not result in a thermal catastrophe, and makes radically different predictions than classic parametric models, such as a mantle thermal peak at the Archean-Proterozoic boundary and slower plate tectonics in the past. Early evidence has been consistent with this new model, and its acceptance in the geological literature has been steadily increasing.