Exploring the electrical conductivity structure of the Cappodacian upper mantle, Türkiye by long-period magnetotellurics

The deep electrical conductivity structure (surface-to-100 km) beneath the Cappadocia Volcanic Province (CVP) in Central Anatolia, Türkiye was examined using three-dimensional magnetotelluric modeling of long-period data (>100 sec) that were collected as part of an U.S. NSF funded multi-disciplinary project titled the Continental Dynamics-Central Anatolian Tectonics (CD-CAT). The long-period dataset comprised seventy-eight observation points distributed on a wide 200 km x 200 km covering Cappadocia. Following the strike angle and dimensionality determination using electromagnetic impedance and phase tensor analyses, inverse models were developed to decipher the conductivity structure of the lower crustal/upper mantle depths beneath regional entities such as Mount Hasan, Mount Erciyes, and Niğde Massif. Some sensitivity tests were performed to control the validity of the key anomalies. The final model suggested that there are apparent high conductivity anomalies beneath these features with mantle roots. As a result, a clear and widespread highly conductive block is observed to be underlying a highly resistive anomaly near the Niğde Massif where the deep anomaly may represent fluid flow beneath the robust massif. As a second important outcome, the model suggested that there are deep conductive anomalies beneath the Hasan and Erciyes volcanoes, which are linked to the shallow potential magma chambers with horizontal dike-like structures.