TY  - JOUR
A1  - Roda-Boluda, Duna C.
A1  - McDonald, Jordan
A1  - Whittaker, Alexander C.
A1  - D'Arcy, Mitchell
T1  - Lithological controls on hillslope sediment supply
BT  - insights from landslide activity and grain size distributions
JF  - Earth surface processes and landforms : the journal of the British Geomorphological Research Group
N2  - The volumes, rates and grain size distributions of sediment supplied from hillslopes represent the initial input of sediment delivered from upland areas and propagated through sediment routing systems. Moreover, hillslope sediment supply has a significant impact on landscape response time to tectonic and climatic perturbations. However, there are very few detailed field studies characterizing hillslope sediment supply as a function of lithology and delivery process. Here, we present new empirical data from tectonically-active areas in southern Italy that quantifies how lithology and rock strength control the landslide fluxes and grain size distributions supplied from hillslopes. Landslides are the major source of hillslope sediment supply in this area, and our inventory of similar to 2800 landslides reveals that landslide sediment flux is dominated by small, shallow landslides. We find that lithology and rock strength modulate the abundance of steep slopes and landslides, and the distribution of landslide sizes. Outcrop-scale rock strength also controls the grain sizes supplied by bedrock weathering, and influences the degree of coarsening of landslide supply with respect to weathering supply. Finally, we show that hillslope sediment supply largely determines the grain sizes of fluvial export, from catchments and that catchments with greater long-term landslide rates deliver coarser material. Therefore, our results demonstrate a dual control of lithology on hillslope sediment supply, by modulating both the sediment fluxes from landslides and the grain sizes supplied by hillslopes to the fluvial system.
KW  - lithology
KW  - hillslopes
KW  - landslides
KW  - grain size
KW  - sediment supply
Y1  - 2018
U6  - https://doi.org/10.1002/esp.4281
SN  - 0197-9337
SN  - 1096-9837
VL  - 43
IS  - 5
SP  - 956
EP  - 977
PB  - Wiley
CY  - Hoboken
ER  - 
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  -