The role of tectonics and magmatism in evolution of Takht-e-Suleiman Travertines, NW Iran

In Takht-e-Suleiman region, travertine deposits are widespread in the footwall of the Chahartagh fault. Three factors played roles in forming travertine in this area: magmatism and high geothermal gradient, existence of carbonates between thermal source at depth and travertine springs on the ground, so that the hydrothermal solution can provide the necessary ingredients for the formation of travertine. The third factor is extensional faults and fractures to conduct water containing dissolved calcium carbonate up to the surface. Absence of travertine on the top of the metamorphic basement, even in the footwall of the Chahartagh fault, highlights the essential role of second factor in formation of the travertine. Sources of travertines in this area are carbonates from the Jangoutaran and Qom formations, with the more emphasis on the latter based on our data. Right-lateral kinematics on the Chahartagh fault led to an NNW extension in the southeastern termination of the fault, paving the way for emergence of the travertine. However, there is evidence for a regional NE extension responsible for NW-SE normal faults in the area. Such an extension may be associated with slab rollback and slab breakoff of the Neotethian oceanic lithosphere, lithosphere delamination deformation or basement-involved thick-skinned deformation in this area.