TY  - JOUR
A1  - Roda-Boluda, Duna C.
A1  - Whittaker, Alexander C.
A1  - Gheorghiu, Delia M.
A1  - Rodes, Angel
A1  - D'Arcy, Mitch
T1  - Be-10 erosion rates controlled by transient response to normal faulting through incision and landsliding
JF  - Earth & planetary science letters
N2  - Quantifying erosion rates, and how they compare to rock uplift rates, is fundamental for understanding landscape response to tectonics and associated sediment fluxes from upland areas. The erosional response to uplift is well-represented by river incision and the associated landslide activity. However, characterising the relationship between these processes remains a major challenge in tectonically active areas, in some cases because landslides can preclude obtaining reliable erosion rates from cosmogenic radionuclide (CRN) concentrations. Here, we quantify the control of tectonics and its coupled geomorphic response on the erosion rates of catchments in southern Italy that are experiencing a transient response to normal faulting. We analyse in-situ Be-10 concentrations for detrital sediment samples, collected along the strike of faults with excellent tectonic constraints and landslide inventories. We demonstrate that Be-10-derived erosion rates are controlled by fault throw rates and the extent of transient incision and associated landsliding in the catchments. We show that the low-relief sub-catchments above knickpoints erode at uniform background rates of similar to 0.10 mm/yr, while downstream of knickpoints, erosion removes similar to 50% of the rock uplifted by the faults, at rates of 0.10-0.64 mm/yr. Despite widespread landsliding, CRN samples provide relatively consistent and accurate erosion rates, most likely because landslides are frequent, small, and shallow, and represent the integrated record of landsliding over several seismic cycles. Consequently, we combine these validated Be-10 erosion rates and data from a geomorphological landslide inventory in a published numerical model, to gain further insight into the long-term landslide rates and sediment mixing, highlighting the potential of CRN data to study landslide dynamics. (C) 2018 Elsevier B.V. All rights reserved.
KW  - cosmogenic nuclides
KW  - erosion rates
KW  - normal faults
KW  - incision
KW  - landslides
KW  - transient response
Y1  - 2019
U6  - https://doi.org/10.1016/j.epsl.2018.11.032
SN  - 0012-821X
SN  - 1385-013X
VL  - 507
SP  - 140
EP  - 153
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Riedl, Simon
A1  - Melnick, Daniel
A1  - Njue, Lucy
A1  - Sudo, Masafumi
A1  - Strecker, Manfred
T1  - Mid-Pleistocene to recent crustal extension in the inner graben of the Northern Kenya Rift
JF  - Geochemistry, geophysics, geosystems
N2  - Magmatic continental rifts often constitute nascent plate boundaries, yet long-term extension rates and transient rate changes associated with these early stages of continental breakup remain difficult to determine. Here, we derive a time-averaged minimum extension rate for the inner graben of the Northern Kenya Rift (NKR) of the East African Rift System for the last 0.5 m.y. We use the TanDEM-X science digital elevation model to evaluate fault-scarp geometries and determine fault throws across the volcano-tectonic axis of the inner graben of the NKR. Along rift-perpendicular profiles, amounts of cumulative extension are determined, and by integrating four new Ar-40/Ar-39 radiometric dates for the Silali volcano into the existing geochronology of the faulted volcanic units, time-averaged extension rates are calculated. This study reveals that in the inner graben of the NKR, the long-term extension rate based on mid-Pleistocene to recent brittle deformation has minimum values of 1.0-1.6 mm yr(-1), locally with values up to 2.0 mm yr(-1). A comparison with the decadal, geodetically determined extension rate reveals that at least 65% of the extension must be accommodated within a narrow, 20-km-wide zone of the inner rift. In light of virtually inactive border faults of the NKR, we show that extension is focused in the region of the active volcano-tectonic axis in the inner graben, thus highlighting the maturing of continental rifting in the NKR.
KW  - extensional tectonics
KW  - Kenya Rift
KW  - TanDEM-X DEM
KW  - DEM analysis
KW  - geochronology
KW  - normal faults
Y1  - 2022
U6  - https://doi.org/10.1029/2021GC010123
SN  - 1525-2027
VL  - 23
IS  - 3
PB  - American Geophysical Union
CY  - Washington
ER  -