HR: 1340h
AN: T33B-1368    [Abstracts]
TI: Thermal regime of young seafloor : how important are the fluids?
AU: * Bonneville, A
EM: bonneville@ipgp.fr
AF: Institut de Physique du Globe de Paris / CNRS, 4, place Jussieu, Paris, 75252, France
AU: Lucazeau, F
EM: lucazeau@ipgp.fr
AF: Institut de Physique du Globe de Paris / CNRS, 4, place Jussieu, Paris, 75252, France
AB: The statistical analysis of the heat-flow data base has been often used to infer general outcomes on the heat transfers and processes throughout continental and oceanic lithospheres. The most important outcome was the relationship between the magnitude of hydrothermal heat-loss and the age of the ocean floor. It caused obviously a declining interest to make new measurements, at least at a funding level, since heat-flow was believed critically perturbed by fluids circulations. However, several recent local or regional studies are not totally consistent with such outcomes. For instance, we recently carried out two marine heat flow surveys on young oceanic sea-floor, one on the mid Atlantic ridge near Azores Islands (Luckyflux cruise, 2003) and the other in the Gulf of Aden (Encensflux cruise, 2006), near the ocean-continent transition and we got surprising results after having processed more than 330 heat flow measurements collected with the POGO method. Off-axis (6-11 Ma) heat flow values in the Atlantic are not all affected by important fluids circulations and almost half of them are quite consistent with conductive cooling models for that age. In the Gulf of Aden, most of the values obtained on the oceanic domain (6-11 Ma) can be considered as not thermally perturbed by fluids. Our results also show that where perturbations exist, basement exposures are present, but not all of these exposures are associated with thermal perturbation. These observations are not only important for the understanding of hydrothermal processes, but also to promote new heat-flow surveys for geodynamics purposes.
DE: 8135 Hydrothermal systems (0450, 1034, 3017, 3616, 4832, 8424)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting