Cyclic evolution of convergent plate margins indicated by time sequence of volcanism and subduction
Hanus, Vaclav; Vanek, Jiri
published: Jan 1, 1996
ArtNo. ESP136000503006, Price: 19.00 €
The time succession and migration of calc-alkaline volcanism in the regions of convergent plate margins is explained by a model presented in this paper. This model is based on (1) the assumption that calc-alkaline volcanism is generated primarily in the intermediate-depth aseismic gap of the subducted lithosphere; and (2) on the combination of the specific distribution and time sequence of volcanism with the geometry of the Wadati-Benioff zone in the Tonga region and Andean South America. The distribution of earthquake foci in subduction zones and the migration of calc-alkaline volcanism indicate that the process of subduction runs in cycles connected with the creation of a system of downgoing slabs descending successively in or against the direction of the ocean floor spreading. The cyclic evolution of convergent plate margins implicates a new interpretation of metallogenic processes in continental wedges overlying subduction zones.