19 Subduction and Collision Processes Through Time in the Mediterranean Area — From the Deep Mantle to the Surface I

Tuesday, 6 September 2011
11:00 AM - 4:30 PM
A 021

SURFACE EXPRESSION OF EASTERN MEDITERRANEAN SLAB DYNAMICS: THE PATTERN AND TIMING OF SURFACE UPLIFT AT THE SOUTHERN MARGIN OF THE CENTRAL ANATOLIAN PLATEAU

Paper number: 19-15
Program: Theme Sessions
Time: 3:50 PM – 4:05 PM

Authors

Abstract

The Central Anatolian plateau in Turkey borders one of the most complex tectonic regions on Earth, where collision of the Arabian plate with Eurasia in Eastern Anatolia transitions to a cryptic pattern of subduction of African beneath Eurasian plate, with concurrent westward extrusion of the Anatolian microplate. Topographic growth of the southern margin of the Central Anatolian plateau has proceeded in discrete stages that can be distinguished based on the outcrop pattern and ages of uplifted marine sediments. These units, together with older basement rocks and younger continental sedimentary fills, also record an evolving pattern of fault deformation that can be used to test the likelihood of different possible uplift mechanisms through time.

Late Miocene marine sediments blanket the SW plateau margin at ca. 1.5 km elevation, while they reach up to ca. 2.0 km elevation along the S and SE margins. We present biostratigraphic age constraints as young as ca. 7 Ma in age on newly-identified marine sediments on the SW plateau margin that lie 100 m stratigraphically higher than those previously described in the literature. Similarities to a previously dated section along the S plateau margin allow us to correlate the regions. Using the mapped pattern of Late Miocene marine sediments throughout the region, together with field observations of onlap surfaces and paleo-shorelines, we reconstructed the cumulative pattern of uplift since marine sediment deposition. The uplift pattern forms a broad anticline, with the greatest uplift focused along the modern plateau margin, and decreasing magnitudes toward the coast and toward the plateau interior. Inversion modeling of fault kinematic indicators measured throughout the region shows contractional deformation that affects all units older than Late Miocene in age, while younger units are affected by extensional and transtensional deformation.

The orientation of slab tears and a slab break-off interpreted from P-wave tomography data appear to align with our reconstructed maximum magnitudes of post-Late Miocene surface uplift in the region. Together with our observations of the changing crustal stress regime, we interpret a close link between mantle processes and the modern surface topography along the southern margin of the Central Anatolian Plateau.