Cyprus Heat Flow with Comments on the Thermal Regime of the Eastern Mediterranean

Abstract

Thirty-three heat flow determinations on Cyprus range from 6–46 mWm−2. There is a systematic distribution to the data, with low values in the Kyrenia Range and Morphou Bay area, intermediate values to the west and south of the Troodos Igneous Massif, and high values in the Mesaoria Plain and Troodos Pillow Lavas. Omitting the very low values, the average heat flow from the 18 most reliable determinations is 28±8 (standard deviation) mWm−2. If a climatic correction is applied, the average is increased to 32 mWm−2. Very low heat flow values probably result from the local mass transfer of heat. A bimodal distribution of the higher determinations can be explained either by thermal refraction within the crust, or as the result of heat transfer by regional water movement. The Cyprus heat flow values do not significantly differ from published marine determinations from the eastern Mediterranean. They do, however, impose constraints on models that can be used to explain the low heat flow. Rapid recent sedimentation has been proposed as a mechanism to explain the low observed marine heat flow values: this would not account for the low heat flow on Cyprus where erosion is taking place. Downward transfer of heat by descending mantle material has also been proposed, but it is not thought that this would produce such a uniformly low heat flow. The eastern Mediterranean heat flow data are consistent with values predicted for a thickly sedimented segment of Mesozoic or older mafic crust, with a stable mantle heat flow contribution, and little or no heat generation in the crust.