TY  - JOUR
A1  - van der Meij, Marijn W.
A1  - Temme, Arnaud J. A. M.
A1  - Wallinga, J.
A1  - Hierold, W.
A1  - Sommer, Michael
T1  - Topography reconstruction of eroding landscapes - A case study from a hummocky ground moraine (CarboZALF-D)
JF  - Geomorphology : an international journal on pure and applied geomorphology
N2  - Erosion processes, aggravated by human activity, have a large impact on the spatial variation of soil and topographic properties. Knowledge of the topography prior to human-induced erosion (paleotopography) in naturally stable landscapes is valuable for identifying vulnerable landscape positions and is required as starting point for erosion modelling exercises. However, developing accurate reconstructions of paleotopography provide a major challenge for geomorphologists. Here, we present a set of paleotopographies for a closed kettle hole catchment in north-east Germany (4 ha), obtained through different reconstruction approaches. Current soil and colluvium thickness, estimated from a dataset of 264 soil descriptions using Ordinary Kriging, were used as input for a mass balance, or were compared with a set of undisturbed soil thicknesses to estimate the amount of erosion. The performance of the different approaches was assessed with cross-validation and the count of mispredicted eroded, depositional or stable landscape positions. The paleotopographic reconstruction approach based on the average thickness of undisturbed soils in the study area showed the best performance. This thickness (1.00 m) is comparable to the average undisturbed soil thickness in the region and in line with global correlations of soil thickness as a function of rainfall and initial CaCO3 content. The performance of the different approaches depended more on mispredictions of landscape position due to the assumption of a spatially constant initial soil depth than on small variations in this depth. To conclude, we mention several methodological and practical points of attention for future topography reconstruction studies, concerning data quality and availability, spatial configuration of data and other processes affecting topography. (C) 2017 Elsevier B.V. All rights reserved.
KW  - Topography reconstruction
KW  - Erosion
KW  - Tillage
KW  - Landscape change
Y1  - 2017
U6  - https://doi.org/10.1016/j.geomorph.2017.08.015
SN  - 0169-555X
SN  - 1872-695X
VL  - 295
SP  - 758
EP  - 772
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - van der Meij, Marijn W.
A1  - Reimann, Tony
A1  - Vornehm, V. K.
A1  - Temme, Arnaud J. A. M.
A1  - Wallinga, Jakob
A1  - van Beek, Roy
A1  - Sommer, Michael
T1  - Reconstructing rates and patterns of colluvial soil redistribution in agrarian (hummocky) landscapes
JF  - Earth surface processes and landforms : the journal of the British Geomorphological Research Group
N2  - Humans have triggered or accelerated erosion processes since prehistoric times through agricultural practices. Optically stimulated luminescence (OSL) is widely used to quantify phases and rates of the corresponding landscape change, by measuring the last moment of daylight exposure of sediments. However, natural and anthropogenic mixing processes, such as bioturbation and tillage, complicate the use of OSL as grains of different depositional ages become mixed, and grains become exposed to light even long after the depositional event of interest. Instead, OSL determines the stabilization age, indicating when sediments were buried below the active mixing zone. These stabilization ages can cause systematic underestimation when calculating deposition rates. Our focus is on colluvial deposition in a kettle hole in the Uckermark region, northeastern Germany. We took 32 samples from five locations in the colluvium filling the kettle hole to study both spatial and temporal patterns in colluviation. We combined OSL dating with advanced age modelling to determine the stabilization age of colluvial sediments. These ages were combined with an archaeological reconstruction of historical ploughing depths to derive the levels of the soil surface at the moment of stabilization; the deposition depths, which were then used to calculate unbiased deposition rates. We identified two phases of colluvial deposition. The oldest deposits (similar to 5 ka) were located at the fringe of the kettle hole and accumulated relatively slowly, whereas the youngest deposits (<0.3 ka) rapidly filled the central kettle hole with rates of two orders of magnitude higher. We suggest that the latter phase is related to artificial drainage, facilitating accessibility in the central depression for agricultural practices. Our results show the need for numerical dating techniques that take archaeological and soil-geomorphological information into account to identify spatiotemporal patterns of landscape change, and to correctly interpret landscape dynamics in anthropogenically influenced hilly landscapes. (c) 2019 The Authors. Earth Surface Processes and Landforms Published by John Wiley & Sons Ltd.
KW  - geochronology
KW  - OSL
KW  - tillage
KW  - erosion
KW  - kettle hole
KW  - hummocky
KW  - landscape evolution
Y1  - 2019
U6  - https://doi.org/10.1002/esp.4671
SN  - 0197-9337
SN  - 1096-9837
VL  - 44
IS  - 12
SP  - 2408
EP  - 2422
PB  - Wiley
CY  - Hoboken
ER  -