Curie point depths based on spectrum analysis of aeromagnetic data, West Anatolian extensional province, Turkey

The Curie point depth map of Western Anatolia was constituted from spectral analysis of the aeromagnetic data. The Curie point depth values from 53 overlapping blocks, 90 x 90 km in size, have been estimated from the band-pass filtered data. The slope of the longest wavelength part of the radially averaged log power spectrum divided by the radial frequency produced the depth to the centroid (z(0)) for the deepest crustal block. The depth to the top (z(t)) was obtained by the slope of the second longest wavelength part of the spectrum. From these depths, the Curie point depth was then calculated by using z(b)=2z(0)-z(t). The Curie point depth estimates for Western Anatolia range between 8.2 and 19.9 km. A corresponding heat-flow map has been constructed from the Curie point depths and thermal conductivity measurements. The boundary between the areas of shallow and deep Curie point depth coincides with an active extensional system which is characterized by a complex cross-cutting horst-graben system. Deepening of Curie point depths (low heat flows) are observed at Hellenic trench axes. The shallow Curie point depths observed in the western part of the study area correspond with recent geological features such as the grabens of the Menderes Massif.