TY  - JOUR
A1  - Haghipour, Negar
A1  - Burg, Jean-Pierre
A1  - Kober, Florian
A1  - Zeilinger, Gerold
A1  - Ivy-Ochs, Susan
A1  - Kubik, Peter W.
A1  - Faridi, Mohammad
T1  - Rate of crustal shortening and non-Coulomb behaviour of an active accretionary wedge - the folded fluvial terraces in Makran (SE, Iran)
JF  - Earth & planetary science letters
N2  - We surveyed fluvial terraces to decipher the Quaternary increment of crustal shortening and shortening rate in the on-shore Makran Accretionary Wedge. We focused on three major catchment basins and associated fold systems. Terrace profiles reconstructed from differential GPS measurements combined with DEM revealed two regional dominant wavelengths, about 5 km in the northern part of the study area and about 15 km to the south. These two wavelengths suggest the existence of two active decollement layers at two rooting depths. The average shortening rate due to folding is estimated at 0.8-1.2 mm/a over the last 130 ka. This accounts for 10-15% of the shortening rate (similar to 8 mm/a) given by kinematic GPS measurements between Chabahar and Bazman and 3% of the convergence between Arabia and Eurasia, across the Makran subduction zone. Despite active deformation and a relatively high shortening rate, the geophysical record shows nearly absent seismic activity in Makran. We propose that strain accumulated in folds over intermediate decollement levels within a thick, incompletely lithified sedimentary cover explains the essentially aseismic, recent tectonics in this region. The importance of folds points to imperfect Coulomb behaviour of the wedge. (C) 2012 Elsevier B.V. All rights reserved.
KW  - fluvial terraces
KW  - Be-10 dating
KW  - accretionary wedge
KW  - shortening rate
Y1  - 2012
U6  - https://doi.org/10.1016/j.epsl.2012.09.001
SN  - 0012-821X
VL  - 355
SP  - 187
EP  - 198
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Hippe, Kristina
A1  - Kober, Florian
A1  - Zeilinger, Gerold
A1  - Ivy-Ochs, Susan
A1  - Maden, Colin
A1  - Wacker, Lukas
A1  - Kubik, Peter W.
A1  - Wieler, Rainer
T1  - Quantifying denudation rates and sediment storage on the eastern Altiplano, Bolivia, using cosmogenic Be-10, Al-26, and in situ C-14
JF  - Geomorphology : an international journal on pure and applied geomorphology
N2  - Denudation processes and sediment transfer are investigated in a high-elevation, low-relief environment (eastern Altiplano, Bolivia) using Be-10, Al-26, and in situ C-14 analysis in fluvial sediments. Concentrations of the long-lived nuclides Be-10 and Al-26 yield consistently low catchment-wide denudation rates of similar to 3-29 mm ky(-1) (integrating over 21-194 ky), which reflect the low geomorphic gradients and the discontinuity of fluvial transport along the eastern Altiplano margin. No significant correlation is recorded between denudation rates of individual catchments and morphological basin parameters (slope, area, elevation). This is attributed to the overall little variability in morphology. The agreement between the denudation rates and published modern sediment discharge data suggests steady landscape evolution of the eastern Altiplano from the latest Pleistocene until today. While Be-10 and Al-26 provide long-term estimates on sediment production, in situ cosmogenic C-14 is used to trace short-term sediment storage. In situ C-14 concentrations are comparatively low indicating that C-14 decayed during alluvial storage over at least the past similar to 11-20 ky. We assume storage at shallow depth (2 m) and consider the influence of soil-mantled hillslopes on the in situ C-14 concentration. Our results illustrate the importance of sediment storage even over short distances and demonstrate the potential of in situ C-14 to study sediment routing and transfer times within drainage systems. However, this study also demonstrates that the long-lived Be-10 and Al-26 nuclides can provide adequate estimates on long-term denudation rates even if sediment transport is not fast but interrupted by several thousands of years of storage.
KW  - Cosmogenic nuclides
KW  - Denudation
KW  - Sediment storage
KW  - In situ C-14
KW  - Altiplano
Y1  - 2012
U6  - https://doi.org/10.1016/j.geomorph.2012.07.031
SN  - 0169-555X
VL  - 179
IS  - 22
SP  - 58
EP  - 70
PB  - Elsevier
CY  - Amsterdam
ER  -