Increase of Seismic Velocities in Upper Oceanic Crust and HydrothermalCirculation in the Juan de Fuca Plate

摘要

Analysis of multi-channel seismic reflection data shows that a significantincrease in seismic velocity occurs in very young upper oceanic crust. This change is coincident with a change in the hydrothermal regime from mainly open to mainly closed and is thought to indicate hydrothermal alteration of the crust. Such extensive alteration was not thought to occur until crust was about 40 Ma prior to this study. This is also the first to link heat flow data to seismic velocities. (AN).