Crustal temperature and mantle heat flow in Europe

Abstract

The map of the surface heat flow in Europe was supplemented by the crustal thickness pattern and data on crustal radioactivity, and transformed to the mantle (Moho) heat flow distribution. Using a model of radioactivity decreasing exponentially with depth A(z)=A 0 exp(− z D ) , with A 0=2μWm −3 and D=10km, we computed generalized one-dimensional, steady-state, conductive temperature-depth curves for the major tectonic units of Europe. The available information on the heat flow-tectonic age. heat flow-heat generation and heat flow-crustal thickness relationships were summarized and discussed in terms of crustal structure. The Mohorovic̆ić discontinuity is clearly not an isothermal surface, neither is the outflow of heat from the upper mantle constant, but both parameters may vary within broad limits. The Moho-temperature can be as low as 280°C in the shield areas; however, it can exceed 900°C in some young intrarnontane depressions or rift structures. Regional variations of the Moho heat flow can be as large as 30–40 mWm −2. The value of the Moho-temperature reflects primarily the tectonic stabilization of the crust as a result of the deep-seated processes in the upper mantle.