TY - JOUR A1 - Schlunegger, Fritz A1 - Norton, Kevin P. A1 - Zeilinger, Gerold T1 - Climatic forcing on channel profiles in the eastern cordillera of the Coroico Region, Bolivia JF - The journal of geology N2 - Orographic precipitation has a large impact on channel morphology and rock uplift via a positive feedback to erosion. We show that in the Eastern Cordillera of Bolivia, channel concavities reach their highest values where annual precipitation increases in the downstream direction, exceeding 3000 mm. The steepest channels are upstream of this zone of high concavity, where precipitation rates are <1000 mm yr(-1). Channels exhibit graded forms both upstream and downstream of this transient reach. We conclude that the prolonged effect of orographic erosion and related tectonic uplift is the preservation of channels with extreme concavities in the Eastern Cordillera. Y1 - 2011 U6 - https://doi.org/10.1086/657407 SN - 0022-1376 VL - 119 IS - 1 SP - 97 EP - 107 PB - Univ. of Chicago Press CY - Chicago ER - TY - JOUR A1 - Calitri, Francesca A1 - Sommer, Michael A1 - Norton, Kevin A1 - Temme, Arnaud A1 - Brandova, Dagmar A1 - Portes, Raquel A1 - Christl, Marcus A1 - Ketterer, Mike E. A1 - Egli, Markus T1 - Tracing the temporal evolution of soil redistribution rates in an agricultural landscape using Pu239+240 and Be-10 JF - Earth surface processes and landforms : the journal of the British Geomorphological Research Group N2 - Two principal groups of processes shape mass fluxes from and into a soil: vertical profile development and lateral soil redistribution. Periods having predominantly progressive soil forming processes (soil profile development) alternate with periods having predominantly regressive processes (erosion). As a result, short‐term soil redistribution – years to decades – can differ substantially from long‐term soil redistribution; i.e. centuries to millennia. However, the quantification of these processes is difficult and consequently their rates are poorly understood. To assess the competing roles of erosion and deposition we determined short‐ and long‐term soil redistribution rates in a formerly glaciated area of the Uckermark, northeast Germany. We compared short‐term erosion or accumulation rates using plutonium‐239 and ‐240 (239+240Pu) and long‐term rates using both in situ and meteoric cosmogenic beryllium‐10 (10Be). Three characteristic process domains have been analysed in detail: a flat landscape position having no erosion/deposition, an erosion‐dominated mid‐slope, and a deposition‐dominated lower‐slope site. We show that the short‐term mass erosion and accumulation rates are about one order of magnitude higher than long‐term redistribution rates. Both, in situ and meteoric 10Be provide comparable results. Depth functions, and therefore not only an average value of the topsoil, give the most meaningful rates. The long‐term soil redistribution rates were in the range of −2.1 t ha‐1 yr‐1 (erosion) and +0.26 t ha‐1 yr‐1 (accumulation) whereas the short‐term erosion rates indicated strong erosion of up to 25 t ha‐1 yr‐1 and accumulation of 7.6 t ha‐1 yr‐1. Our multi‐isotope method identifies periods of erosion and deposition, confirming the ‘time‐split approach’ of distinct different phases (progressive/regressive) in soil evolution. With such an approach, temporally‐changing processes can be disentangled, which allows the identification of both the dimensions of and the increase in soil erosion due to human influence KW - soil erosion KW - Be-10 KW - Pu239+240 KW - temporal evolution KW - moraine landscape KW - agricultural soils Y1 - 2019 U6 - https://doi.org/10.1002/esp.4612 SN - 0197-9337 SN - 1096-9837 VL - 44 IS - 9 SP - 1783 EP - 1798 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Savi, Sara A1 - Norton, Kevin P. A1 - Picotti, Vincenzo A1 - Akcar, Naki A1 - Delunel, Romain A1 - Brardinoni, Francesco A1 - Kubik, Peter A1 - Schlunegger, Fritz T1 - Quantifying sediment supply at the end of the last glaciation: Dynamic reconstruction of an alpine debris-flow fan JF - Geological Society of America bulletin N2 - In this paper we quantify the sediment dynamics in the formerly glaciated Zielbach catchment in the Italian Alps from the end of the Last Glacial Maximum (LGM) until today. As a basis for our quantification, we use the stratigraphic record offered by a 3.5 km(2) large fan that we explore with a seismic survey, stratigraphic analyses of drillhole material, and C-14 ages measured on organic matter encountered in these drillings. In addition, we calculate past denudation rate variability in the fan deposits using concentrations of cosmogenic Be-10. We merge this information into a scenario of how the sediment flux has changed through time and how this variability can be related to climatic variations, framed within well-known paraglacial models. The results document a highly complex natural system. From the LGM to the very early Holocene, ice-melted discharge and climate variability promoted a high sediment flux (sedimentation rate up to 40 mm/yr). This flux then dramatically decreased toward interglacial values (0.8 mm/yr at 5-4 calibrated kyr B.P.). However, in contrast to the trend of classic paraglacial models, the flux recorded at Zielbach shows secondary peaks at 6.5 ka and 2.5 ka, with values of 13 mm/yr and 1.5 mm/yr, respectively. Paleo-denudation rates also decrease from similar to 33 mm/yr at the beginning of the Holocene to 0.42 mm/yr at 5 ka, with peaks of similar to 6 mm/yr and 1.1 mm/yr at 6.5 ka and 2.5 ka. High-amplitude climate change is the most likely cause of the secondary peaks, but anthropogenic activities may have contributed as well. The good correlation between paleo-sedimentation and paleo-denudation rates suggests that the majority of the deglaciated material destocked from the Zielbach catchment is stored in the alluvial fan. Y1 - 2014 U6 - https://doi.org/10.1130/B30849.1 SN - 0016-7606 SN - 1943-2674 VL - 126 IS - 5-6 SP - 773 EP - 790 PB - American Institute of Physics CY - Boulder ER -