On the geothermal regime of the foreland of the Eastern Carpathians bend

Abstract

Detailed high resolution temperature logs were obtained in 41 thermally stabilized boreholes in the Eastern Carpathians bend and its foreland. The investigated depth ranges from 0–500 to 0–2500 m. The temperature logs show (a) a wide range of geothermal gradients, from as low as 23 mK m −1 (foredeep), to 37 and 53 mK m −1 at the external limit of the foredeep and on the foreland platform, and (b) a second-order feature, namely a curvature indicating a general increase of the gradient with depth. The new temperature data are discussed in terms of thermal effects of sedimentation, palaeoclimate changes of the Earth's surface temperature, and fluid flow, which contribute to the observed curvature of temperature profiles in the investigated depth interval. The discussion is illustrated with data concerning two of the deepest logged boreholes and a profile through the centre of the foredeep basin.