Two Accretion Types of Intraoceanic Island Arcs in the Koryak-Kamchatka Region

摘要

The mechanism and consequences of island arc accretion, which are reflected in the recent structure, remain an important topic in the literature. The first ideas about the wedging-up of subduction zones by oceanic volcanic uplifts and intraoceanic island arcs [1] appeared to be oversimplified. A decade later, M. Cloos showed that oceanic volcanic uplifts and intraoceanic island arcs with the Earth's crust as thick as 17 km do not wedge-up subduction zones when approaching them but partially or completely become subducted. Applying calculations, the process was explained by the fact that areas of oceanic lithospheric plates carrying such uplifts exhibit negative buoyancy with respect to the asthenosphere [2].