THE PHYSIOGRAPHIC RESPONSE TO CENOZOIC DRIP TECTONICS IN CENTRAL ANATOLIA

Lithospheric dripping is often invoked to reconcile the rapid surface uplift of orogenic plateaus globally. Rapid surface uplift motivates changes in climate and precipitation, which focuses erosion and generates relief. Thus, understanding when and where lithospheric dripping events occurred within the Central Anatolian Plateau has important implications for the drivers of speciation, basin architecture, and the distribution of natural resources. Here, we propose that the present-day physiography of the Central Anatolian Plateau is in part a result of a ~10,000 km² lithospheric foundering event from 37–35 Ma along the Izmir-Ankara-Erzincan suture zone in the Çankiri basin region, and a more recent ~40,000 km² event that occurred within the southern Tauride, Konya basin region.

In detail, marine sedimentation within the Çankiri basin transitions to purely terrestrial deposition from 42–37 Ma, defined by a ~1 km thick section of interfingering fluvial and evaporite-bearing lacustrine deposits until 32 Ma. Shortly after 32 Ma the Çankiri basin was structurally inverted. A basin-wide unconformity bevels inverted terrestrial sequences above which multi-meter thick, gnarled Miocene evaporite sequences are present. West of the Çankiri basin, Miocene adakite-like magmatism initiated within the Galatean Volcanic Province as contractional deformation transitioned to transcurrent tectonics. Furthermore, we observe a rapid decrease in detrital zircon εHf values at ~37 Ma followed by a rapid increase at ~35 Ma, which we interpret as additional evidence for the growth and removal of a lithospheric welt. Today, along the southern margin of the Central Anatolian Plateau, the southern Tauride, Konya basin region is defined by a rigid, ~1 km high, low-relief, internally drained, diamond-shaped depression bordered by active strike-slip faults – broadly consistent with lithospheric dripping analogs in the Bolivian Altiplano.