Quaternary E-W Extension Uplifts Kythira Island and Segments the Hellenic Arc


de Gelder G., Fernandez-Blanco D., Öğretmen N., Liakopoulos S., Papanastassiou D., Faranda C., ...More

TECTONICS, vol.41, no.10, 2022 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 41 Issue: 10
  • Publication Date: 2022
  • Doi Number: 10.1029/2022tc007231
  • Journal Name: TECTONICS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aquatic Science & Fisheries Abstracts (ASFA), Compendex, Environment Index, Geobase, INSPEC
  • Keywords: Kythira, Hellenic Arc, marine terraces, sedimentary basins, uplift, normal faults, INFLUENCE FAULT DEVELOPMENT, NORTH ANATOLIAN FAULT, EAST-WEST EXTENSION, SEA-LEVEL, CORINTH RIFT, ACTIVE TECTONICS, LATE PLEISTOCENE, SUBDUCTION ZONE, MARINE, GREECE
  • Istanbul Technical University Affiliated: Yes

Abstract

Several crustal and lithospheric mechanisms lead to deformation and vertical motion of the upper plate during subduction, but their relative contribution is often enigmatic. Multiple areas of the Hellenic Forearc have been uplifting since Plio-Quaternary times, yet spatiotemporal characteristics and sources of this uplift are poorly resolved. The remarkable geology and geomorphology of Kythira Island, in the southwestern Hellenic forearc, allow for a detailed tectonic reconstruction since the Late Miocene. We present a morphotectonic map of the island, together with new biostratigraphic dating and detailed analyses of active fault strikes and marine terraces. We find that the Tortonian-Pliocene stratigraphy in Kythira records similar to 100 m of subsidence, and a wide coastal rasa marks the similar to 2.8-2.4 Ma maximum transgression. Subsequent marine regression of similar to 300-400 m and minor E-W tilt are recorded in similar to 12 marine terrace levels for which we estimate uplift rates of similar to 0.2-0.4 mm/yr. Guided by simple landscape evolution models, we interpret the coastal morphology as the result of initial stability or of slow, gradual sea-level drop since similar to 2.8-2.4 Ma, followed by faster uplift since similar to 1.5-0.7 Ma. Our findings on- and offshore suggest that E-W extension is the dominant mode of regional active upper crustal deformation, and N-S normal faults accommodate most, if not all of the uplift on Kythira. We interpret the initiation of E-W extension as the result of a change in plate boundary conditions, in response to either propagation of the North Anatolian Fault, incipient collision with the African plate, mantle dynamics or a combination thereof.