Multi-phased uplift of the southern margin of the Central Anatolian plateau, Turkey: A record of tectonic and upper mantle processes

Uplifted Neogene marine sediments and Quaternary fluvial terraces in the Mut Basin, southern Turkey, reveal a detailed history of surface uplift of the southern margin of the Central Anatolian plateau from the Late Miocene to the present. New surface exposure ages (10Be, 26Al and 21Ne) of gravels above fluvial strath terraces located between 28 and 135 m above the modern Göksu River in the Mut Basin yield ages ranging from ca. 25 to 130 ka, or an average incision rate of 0.52 to 0.67 mm/yr. Published biostratigraphic data together with new interpretations of the fossil assemblages from uplifted marine sediments reveal average uplift rates of 0.25 to 0.37 mm/yr since Late Miocene time (starting between 8 and 5.45 Ma), and 0.72 to 0.74 mm/yr after 1.62 to 1.66 Ma. Together with the terrace ages, the data imply 0.6 to 0.7 mm/yr surface uplift rates from 1.6 Ma to the present. The difference between the post-Late Miocene and post-1.6 Ma surface uplift rates can be reconciled by increasing uplift rates through time (though they have been relatively steady since 1.6 Ma), or by multi-phased uplift with slow uplift or subsidence in between. Longitudinal profiles of rivers in the upper catchment of the Mut-Ermenek Basin show no apparent lithologic or fault control on knickpoints that occur at 1.2 to 1.5 km elevation, implying a transient response to a change in uplift rates. Projections of graded upper relict channel segments to the modern outlet, together with constraints from uplifted marine sediments show that a slower incision/uplift rate of ca. 0.1 mm/yr preceded the 0.7 mm/yr uplift rate. The river morphology and profile projections therefore suggest that the southern margin of the plateau was characterized by multi-phased uplift, rather than by steadily increasing uplift rates. Multi-phased uplift can be explained by surface uplift above a slab break-off and possibly also the arrival of the Eratosthenes Seamount at the collision zone south of Cyprus.