Heat Flow and Geodynamics of the Shatsky and Hess Rises (Pacific Ocean)

摘要

Using the heat flow data,we calculated the age of the Shatsky (approx140 My) and Hess (approx100 My) rises,which correspond to the ages determined from the magnetic data.The thicknesses of the lithospheres of the rises (80-90 km) close to that of the adjacent oceanic plates were also calculated.This suggests the formation of the rises is close to a spreading axis.It is concluded that the rises formed independent structures,and their geothermal evolution proceeded in accordance with the crystallization model of formation of the ocean floor.We performed a tectonic analysis of the northern part of the Pacific Ocean and suggested a geodynamical model for formation of the Shatsky and Hess rises in the period 140-83.5 My BP According to this model,the rises were formed in the region of a triple junction point between the Izanagi,Farallon,and Pacific plates,which is also confirmed by the data of heat flow studies.