Cenozoic Tectonic Evolution of the Sivas Basin from Subduction to Collision to Escape in Central Anatolia, Turkey
General Material Designation
[Thesis]
First Statement of Responsibility
Darin, Michael Harrison
Subsequent Statement of Responsibility
Umhoefer, Paul J.
.PUBLICATION, DISTRIBUTION, ETC
Name of Publisher, Distributor, etc.
Northern Arizona University
Date of Publication, Distribution, etc.
2019
GENERAL NOTES
Text of Note
392 p.
DISSERTATION (THESIS) NOTE
Dissertation or thesis details and type of degree
Ph.D.
Body granting the degree
Northern Arizona University
Text preceding or following the note
2019
SUMMARY OR ABSTRACT
Text of Note
Continental collisions exert a profound influence over the kinematic and dynamic evolution of orogens. One of the most unique and puzzling consequences of some collisions is the lateral extrusion or 'escape' of continental blocks away from the collision zone, typically facilitated by lithosphere-scale strike-slip fault systems. Despite significant progress in understanding a world-class example of active tectonic escape in Anatolia (Turkey), the timing of continental collision and the driving geodynamic mechanisms responsible for the transition from collision to tectonic escape remain poorly understood and controversial. This dissertation presents new detailed geologic mapping, structural and stratigraphic analyses, and low-temperature thermochronology data from the Sivas Basin in central Anatolia, and a regional-scale tectonic reconstruction model since ~55 Ma. Collectively, these data sets provide valuable new constraints on the timing, magnitude, and style of upper-crustal deformation associated with terminal Arabia-Eurasia collision and Anatolian escape. Widespread contraction and exhumation began at ~40-35 Ma drove a switch from marine to nonmarine sedimentation and structurally partitioned the Sivas Basin into a southern wedge-top and northern foreland basin separated by the southern Sivas fold-thrust belt. Episodic contraction occurred in short, ~3-5-Myr pulses within the basin and in the Tauride thrust belt to the south until the late Miocene. The end of contraction and the start of regional plateau uplift by ~7 Ma marked a major transition in the Sivas Basin to lacustrine sedimentation and intraplate strike-slip faulting, reflecting the development and westward escape of the Anatolia microplate. Regional-scale compilations of geochronology, thermochronology, crustal shortening, and plate kinematic constraints form the basis for a new plate tectonic reconstruction that provides crucial insights into the plate-scale evolution and geodynamics of collision and escape. In this model, initial collision of the thinned Arabia passive margin with Eurasia first occurred at ~45 Ma in eastern Anatolia and was diachronous and progressively younger along-strike toward the southeast along the Zagros Mountains. The arrival of unextended and relatively thick Arabian crust at the Bitlis-Zagros suture led to hard collision by ~20-15 Ma in Anatolia and a reduction in plate convergence rates and accelerated trench retreat and extension in the Aegean, which ultimately facilitated the development and full westward tectonic escape of the Anatolian microplate by ~7-5 Ma.