A Numerical Study of Mantle Tectonic Flow as Relevant to the Cenozoic Structural Development of the East Asiatic Transition Zone

Abstract

Based on an examination of historical sequence of the Cenozoic events in the East Asiatic transition zone, it is assumed that, at some stage of the Early Cenozoic, there was a significant difference in the temperature of the upper mantle between the two sides of the Japanese Islands, higher on the side under the Japan Sea and lower on the side under the northwestern Pacific Ocean. The mechanical aspect of mantle tectonic flow which could be generated as a result of this difference is numerically investigated with the use of the SOR method in combination with the MAC method. The basic features of fluid flow observed from the calculated result have significant implications with regard to the Cenozoic structural development of the East Asiatic transition zone, in support of the proposition that the density-driven differential mantle flow played a prominent role in the development of the present-day structure of the transition zone.