Original paper

Exhumation and uplift of an segmented active fore-arc in Space and Time, Kamchatka, Russian Federation

Freitag, Ralf; Pflanz, Dorthe; Tsukanov, Nikolay; Baranov, Boris

Abstract

The growth of continental crust by accretion of allochtonousterranes at the activ margin of Kamchatka is documented since mesocoic times. This growth is expressed by differential uplift and exhumation of seismotectonic and morphotectonic blocks of the accretionary wedge along the Kamchatka trench. Kinematics of uplift and exhumation must be grasped by analysing the deformation with structural and neotectonic matters and quantifiedby thermochronologicalmethods up to Lower Pliocene times. Due to differential uplift of seismotectonic blocks and sea level changes, numerous (sub-)recent marine and alluvial terraces have been formed on Kamchatka. Radiometric dating of these terraces allows the documentationand quantification of the relative vertical movement of the seismotectonic blocks with very high resolution up to recent times. We need to understand and characterise the coherence between lower plate convergence (of geometry, direction, velocity) and upper plate deformation, in other words the seismical and mechanical couplingbetween upper and lower plate along the Kamchatkatrench trough time.