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Debris-flow–dependent variation of cosmogenically derived catchment-wide denudation rates

2012; Geological Society of America; Volume: 40; Issue: 10 Linguagem: Inglês

10.1130/g33406.1

1943-2682

Florian Kober, Kristina Hippe, Bernhard Salcher, Susan Ivy‐Ochs, Peter W. Kubik, Lukas Wacker, Nils Hählen,

Hydrology and Sediment Transport Processes

Research Article| October 01, 2012 Debris-flow–dependent variation of cosmogenically derived catchment-wide denudation rates F. Kober; F. Kober * 1Institute of Geology, ETH Zürich, 8092 Zürich, Switzerland *E-mail: kober@erdw.ethz.ch. Search for other works by this author on: GSW Google Scholar K. Hippe; K. Hippe 2Institute of Geochemistry and Petrology, ETH Zürich, 8092 Zürich, Switzerland Search for other works by this author on: GSW Google Scholar B. Salcher; B. Salcher 1Institute of Geology, ETH Zürich, 8092 Zürich, Switzerland Search for other works by this author on: GSW Google Scholar S. Ivy-Ochs; S. Ivy-Ochs 3Institute of Ion Beam Physics, ETH Zürich, 8093 Zürich, Switzerland Search for other works by this author on: GSW Google Scholar P.W. Kubik; P.W. Kubik 3Institute of Ion Beam Physics, ETH Zürich, 8093 Zürich, Switzerland Search for other works by this author on: GSW Google Scholar L. Wacker; L. Wacker 3Institute of Ion Beam Physics, ETH Zürich, 8093 Zürich, Switzerland Search for other works by this author on: GSW Google Scholar N. Hählen N. Hählen 4Oberingenieurkreis I, Tiefbauamt des Kantons Bern, 3601 Thun, Switzerland Search for other works by this author on: GSW Google Scholar Author and Article Information F. Kober * 1Institute of Geology, ETH Zürich, 8092 Zürich, Switzerland K. Hippe 2Institute of Geochemistry and Petrology, ETH Zürich, 8092 Zürich, Switzerland B. Salcher 1Institute of Geology, ETH Zürich, 8092 Zürich, Switzerland S. Ivy-Ochs 3Institute of Ion Beam Physics, ETH Zürich, 8093 Zürich, Switzerland P.W. Kubik 3Institute of Ion Beam Physics, ETH Zürich, 8093 Zürich, Switzerland L. Wacker 3Institute of Ion Beam Physics, ETH Zürich, 8093 Zürich, Switzerland N. Hählen 4Oberingenieurkreis I, Tiefbauamt des Kantons Bern, 3601 Thun, Switzerland *E-mail: kober@erdw.ethz.ch. Publisher: Geological Society of America Received: 12 Mar 2012 Revision Received: 19 Apr 2012 Accepted: 24 Apr 2012 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2012 Geological Society of America Geology (2012) 40 (10): 935–938. https://doi.org/10.1130/G33406.1 Article history Received: 12 Mar 2012 Revision Received: 19 Apr 2012 Accepted: 24 Apr 2012 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation F. Kober, K. Hippe, B. Salcher, S. Ivy-Ochs, P.W. Kubik, L. Wacker, N. Hählen; Debris-flow–dependent variation of cosmogenically derived catchment-wide denudation rates. Geology 2012;; 40 (10): 935–938. doi: https://doi.org/10.1130/G33406.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Catchment-wide denudation rates (CWDRs) obtained from cosmogenic nuclides are an efficient way to determine geomorphic processes quantitatively in alpine mountain ranges over Holocene time scales. These rate estimations assume steady geomorphic processes. Here we use a time series (3 yr) in the Aare catchment (central Swiss Alps) to test the impact of spatially heterogeneous stochastic sediment supply on CWDRs. Our results show that low-frequency, high-magnitude debris-flow events significantly perturb cosmogenic nuclide (10Be, 14C) concentrations and thus CWDRs. The 10Be concentrations decrease by a factor of two following debris-flow events, resulting in a doubling of inferred CWDRs. The variability indicates a clear time and source dependency on sediment supply, with restricted area-weighted mixing of sediment. Accordingly, in transient environments, it is critical to have an understanding of the history of geomorphic processes to derive meaningful CWDRs. We hypothesize that the size of debris flows, their connectivity with the trunk stream, and the ability of the system to sufficiently mix sediment from low- and high-order catchments control the magnitude of CWDR perturbations. We also determined in situ 14C in a few samples. In conjunction with 10Be, these data suggest partial storage for colluvium of a few thousand years within the catchment prior to debris-flow initiation. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.