ALBERT

Description: 〈span〉The Almacık Block is an approximately 73 km long and 21 km wide tectonic sliver formed by the North Anatolian Fault Zone in northwestern Turkey. Morphologically, it is one of the most pronounced structures along the North Anatolian Fault Zone. All the segments bounding the Almacık Block were ruptured during the second half of the 20th century. The fifty-four apatite (U–Th)/He ages we obtained showed that the region including the Almacık Block was exhumed during the Oligo–Miocene interval and then original exhumation pattern was distorted by the North Anatolian Fault Zone during the Miocene to recent. To interpret this distortion and to reconstruct it to the original state, we modelled “Λ”-shaped mountain fronts in the most probable deformation scenarios. The block has been tilted southward about an approximately east–west-trending horizontal (slightly dipping to the east) axis. As a result of this rotation, the northern part of the block has been uplifted about 2800 m, whereas the southern part has subsided about 430 m, likely during the last 2.5 Myr. The exhumation in the studied region started at around 34 Ma and lasted until 16 Ma with a mean exhumation rate of about 60 m/Myr.〈/span〉

Description: 〈span〉The Suluova Basin is a prominent member of the wide transtensional Amasya Shear Zone located at the central part of the North Anatolian Shear Zone. This basin is crucial and provides well-resolved data to understand the evolution of transtensional tectonic zones as well as the morphological and paleoenvironmental changes of North Anatolia during the Quaternary. Analysis of detailed stratigraphical sections, faulting data, and mammal paleontology reveals that the Suluova Basin has started to evolve as a closed half-graben along the NW–SE-trending, SW-dipping basin bounding fault zone with normal slip in the early Quaternary. Initial sedimentation mode of the basin was dominated by alluvial fan facies associations. Progressive basin subsidence resulted in an expansion of a freshwater lake at the basin depocenter as faults propagated westwards. Further extensions in the basin were caused to initiate the E–W-trending southern tectonic boundary. Newly created accommodation space hosted a vast freshwater lake during the Calabrian (∼1.8–0.78 Ma) acting as a refugia for a rich faunal assemblage of large and small land mammals. The conditions prior to the onset of Middle Pleistocene (MIS19, ∼0.79 Ma) is marked with increasing regional erosion where paleo-Lake Suluova was captured by the regional river system. Synchronously, the next phase of the shear zone formation was introduced with E–W-trending dextral and NE–SW-trending sinistral strike-slip faults, cross-cutting the former basin structure, forming new depocenters. These faults are still active with noticeable seismic activity and comprise future risks for the major cities of the region.〈/span〉