The subsidence of aseismic ridges

Abstract

All available Deep Sea Drilling Project results from aseismic ridges have been compiled. These results indicate that at least five major aseismic ridges — the Ninetyeast Ridge, the Rio Grande Rise, the Walvis Ridge, the Chagos-Laccadive Ridge and the southeast Mascarene Plateau — have formed close to sea level and have since subsided at rates comparable to that of normal oceanic crust. Two other aseismic ridges, the Iceland-Faeroe Ridge and Broken Ridge, may have undergone a similar but more complicated subsidence history. This subsidence is attributed entirely to the cooling and contraction of the lithospheric plate on which these ridges are built. Some geological and geophysical implications of this model are discussed including its applicability to the subsidence of oceanic island chains.