Morphometric age estimate of the last phase of accelerated uplift in the Kazdag area (Biga Peninsula, NW Turkey)

Abstract

Keywords:Aegean domain North Anatolian Fault Zone Morphometry R/S R index Drainage network Uplift While the Plio-Quaternary uplift of the Kazdag mountain range (Biga Peninsula, NW Turkey) is generally acknowledged, little is known about its detailed timing. Partly because of this lack of data, the cause of this uplift phase is also debated, being associated either to back-arc extension in the rear of the Hellenic subduction zone, to transpression along the northern edge of the west-moving Anatolian microplate, or to extension driven by gravitational collapse. Here, we perform a morphometric study of the fluvial landscape at the scale of the Biga Peninsula, coupling the recently developed R/S R analysis of the drainage network with concavity and steepness measures of a set of 29 rivers of all sizes. While the dependence of profile concavity on basin size confirms that the landscape of the peninsula is still in a transient state, the spatial distribution of profile steepness values characterized by higher values for streams flowing down from the Kazdag massif shows that the latter undergoes higher uplift rates than the rest of the peninsula. We obtain a S R value of 0.324 ± 0.035 that, according to the relation established by Demoulin (2012), yields an age range of 0.5-1.3 Ma and a most probable value of 0.8 Ma for the time of the last tectonic perturbation in the region. In agreement with the analysis of knickpoint migration in a subset of rivers, this suggests that a pulse of uplift occurred at that time and, corroborated by sparse published observations in the Bayramiç and Çanakkale depressions, that the peninsula was uplifted as a whole from that time. This uplift pulse might have been caused by transient compressive conditions in the Anatolian plate when the Eratosthenes seamount came to subduct beneath the Cyprus arc around the early-to-mid Pleistocene transition (Schattner, 2010).

Patterns of Quaternary uplift of the Corinth rift southern border (N Peloponnese, Greece) revealed by fluvial landscape morphometry

“…In spite of the effect of differential block uplift, which affects to some degree almost all catchments, H b shows a weak but significant negative correlation with drainage area A (p = 0.072). The existence of such a correlation is generally thought to indicate a transient state of landscape disequilibrium (Chen et al, 2003;Demoulin et al, 2013), which is consistent here with the characteristics of the river long profiles (see below). Interestingly, using the residuals of the H b =f(lnA) regression improves the general shape of their observed E-W changes (Fig.…”

“…A further advantage of this approach is its capacity to enhance potential streamwise changes in S R in relation with the N-S succession of faulted blocks. Demoulin et al (2013) show that the impact of other external controls on the relation between S R and time (e.g., direct controls on incision rate, such as rock resistance and climate, noise in the R measurements caused by strongly non-dendritic patterns of tributary networks) is minor in most cases.…”

“…The dominant characteristic of downstream S R values (Table 1), indicative of the most recent uplift episode, is that they are all very large (between 1.8 and 10.3), much larger than the values recorded elsewhere, which never exceed 1 (Demoulin, 2012;Demoulin et al, 2013). The only circumstance in which comparably high S R values were observed was when the R/S R analysis was applied to synthetic landscapes (Croissant, 2012).…”

“…4), thus describing three nested morphological levels respectively indicative of the long-, middle-, and short-term components of the landscape response, where l* is the dimensionless expression of length (for H r and H n ) or area (for H b ). This raw measure of R is then corrected for the effect of the drainage network's branching level, the correction factor relying on a measure of catchment elongation E, calculated as with L b = maximal length of the catchment, measured from its outlet (Demoulin, 2012;Demoulin et al, 2013).…”

Plio-Quaternary kinematic development and paleostress pattern of the Edremit Basin, western Turkey

“…This continental scale structure is observable as a complex fault system due to branching into different strands, particularly in the Marmara region of Turkey, and represents various geometric, geomorphic and kinematic features (e.g. Gürer et al, 2003Gürer et al, , 2006Gürbüz and Gürer, 2009;Kürçer et al, 2008;Demoulin et al, 2013;Selim et al, 2013). As a result of these features, the strike-slip deformation of the NAFS is laterally discontinuous in and around the Biga Peninsula and subdivided into different major enéchelon faults that partially overstepped to form pull-apart and pushup structures.…”