Emplacement of volcanic vents and geodynamics of Central Anatolia, Turkey


JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH, vol.85, pp.33-54, 1998 (SCI-Expanded) identifier identifier


Observations on Synthetic Aperture Radar (SAR) scenes of the European Remote Sensing (ERS) satellite and Digital Elevation Models (DEMs), complemented by field structural analysis permit a new understanding of relationships between tectonics and volcanism since the late Miocene (10 Ma) in Central Anatolia. Volcanic edifices form elongate stratovolcanoes, linear clusters and volcanic ridges. They indicate emplacement on tension fractures and tail-crack or horsetail features. For instance, the Kara Dag volcano is rooted on a tail-crack which accommodates a horizontal left-lateral throw component at a fault termination. Caldera complexes of Cappadocia are associated with horsetail fault patterns. The emplacement of volcanoes also benefits from larger-scale tectonic structures: the Erciyes Dag volcano is localized by the Sultan Sat releasing bend which opens along the sinistral strike-slip Ecemis fault. Deformation has been analysed from tension fractures-which are perpendicular to the direction of extension-and from field structural analysis. On a regional scale, the tectonic regime responsible for the distribution of volcanic vents in this area of convergence and lateral extrusion, is not compression but extension. The Central Taurus range is the thermally uplifted shoulder of the Adana-Cilicia basin, which is related to lithosphere thinning. Westward movements in the northwestern part of the studied area are influenced by the active back-are Aegean extension situated to the west. Farther to the south, the direction of motion turns southwest and south, under the influence of the opening of the Adana-Cilicia basin. We interpreted that extension in the Central Anatolian plateau is related to crustal blocks moving above sub-horizontal detachment surfaces located in the lower crust. This is based on several facts: the Tuz Golu fault zone is a within-crust detachment; the Tuz Golu basin does not affect the whole lithosphere because otherwise it would have been bordered by thermally uplifted shoulders; movements change trend within a small (50 km) region. (C) 1998 Elsevier Science B.V. All rights reserved.