The Late Pleistocene-Holocene evolution of the Adapazarı Basin was investigated using the stratigraphy, geometry, and absoluteluminescence dating of the 4-step fluvial terrace staircases of the Sakarya River. The results revealed that the fluvial cycle was primarily related to relative sea level changes of the Black Sea. The initiation of deposition and the abandonment ages of the terraces indicated relative high stands during marine isotope stage (MIS) 5a (~84–72 ka), 3 (40–30 ka), and 1 (9 ka-recent). The erosional periods in between the terrace steps reflected the response of the Sakarya River to the significantly low stands of the sea. | Turkish Journal of Earth Sciences Turkish J Earth Sci 2021 30 93-115 http earth TÜBİTAK Research Article doi yer-2006-25 Late Pleistocene-Holocene characteristics of the North Anatolian Fault at Adapazarı Basin evidence from the age and geometry of the fluvial terrace staircases 1 2 Mehmet Korhan ERTURAÇ 1 Department of Geography Faculty of Arts and Sciences Sakarya University Sakarya Turkey 2 Research Development and Application Center Sakarya University Sakarya Turkey Received Accepted Published Online Final Version Abstract The Late Pleistocene-Holocene evolution of the Adapazarı Basin was investigated using the stratigraphy geometry and absoluteluminescence dating of the 4-step fluvial terrace staircases of the Sakarya River. The results revealed that the fluvial cycle was primarily related to relative sea level changes of the Black Sea. The initiation of deposition and the abandonment ages of the terraces indicated relative high stands during marine isotope stage MIS 5a 84 72 ka 3 40 30 ka and 1 9 ka-recent . The erosional periods in between the terrace steps reflected the response of the Sakarya River to the significantly low stands of the sea. The spatiotemporal position of the high terraces T4 and T3 yielded an average of mm year and uniform and aseismic rock uplift rate for the NW part of the Anatolian Plate bounded by the North Anatolian Fault which ruptured during the 1999 İzmit earthquake. The lower terrace T1 was previously used to determine the horizontal slip rate of the Sapanca-Akyazı segment of the earthquake rupture and reported as mm year. Further displacement measurements from the surfaces of T2 and T1 yielded a vertical slip rate of mm year calculated for the Late Holocene. Extrapolation of these 2 vertical rates to the south and north of the fault zone in time and space used in conjunction with the stratigraphy and geometry of the Adapazarı Basin
