HEATFLOW DENSITY DISTRIBUTION IN THE RED-SEA

A new heatflow density (HFD) map of the Red Sea was compiled from 467 heatflow density values collected by various organisations during the last 20 years. The map shows that the complicated heatflow distribution can only be explained if we assume considerable convective transport of heat through water circulating in the sediments and crust, as well as convection in small volumes of mobilized magma associated with the deeps along the morphologic depression of the Red Sea. The HFD values are twice as high as the world mean at the flanks of the rift and reach values of 5 to 8 times the world mean in the graben and the deeps. One-dimensional stationary computations of the distribution of the isotherms showed that at 15 to 18 km depth the temperatures are sufficiently high to partially mobilize the upper mantle. Distribution of the HFD anomalies can only be explained if we assume that part of the rift development can be accounted for by the development of pull-apart basins that dominated the early stages of rifting and pure shear combined with wrench faulting active now.