Holocene alluvial-fan development in the Macgillycuddyʼs Reeks, southwest Ireland

Research Article| December 01, 2000 Holocene alluvial-fan development in the Macgillycuddy's Reeks, southwest Ireland E. Anderson; E. Anderson 1School of Geography and Environmental Management, Middlesex University, Queensway, Enfield EN3 4SF, UK Search for other works by this author on: GSW Google Scholar S. Harrison; S. Harrison 2Centre for Quaternary Science, Geography, NES, Coventry University, Priory Street, Coventry CV1 5FB, UK Search for other works by this author on: GSW Google Scholar D.G. Passmore; D.G. Passmore 3Department of Geography, University of Newcastle-upon-Tyne, Newcastle-upon-Tyne NE1 8ST, UK Search for other works by this author on: GSW Google Scholar T.M. Mighall T.M. Mighall 4Centre for Quaternary Science, Geography, NES, Coventry University, Priory Street, Coventry CV1 5FB, UK Search for other works by this author on: GSW Google Scholar Author and Article Information E. Anderson 1School of Geography and Environmental Management, Middlesex University, Queensway, Enfield EN3 4SF, UK S. Harrison 2Centre for Quaternary Science, Geography, NES, Coventry University, Priory Street, Coventry CV1 5FB, UK D.G. Passmore 3Department of Geography, University of Newcastle-upon-Tyne, Newcastle-upon-Tyne NE1 8ST, UK T.M. Mighall 4Centre for Quaternary Science, Geography, NES, Coventry University, Priory Street, Coventry CV1 5FB, UK Publisher: Geological Society of America Received: 08 Mar 1999 Revision Received: 07 Feb 2000 Accepted: 09 Feb 2000 First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2000) 112 (12): 1834–1849. https://doi.org/10.1130/0016-7606(2000)112<1834:HAFDIT>2.0.CO;2 Article history Received: 08 Mar 1999 Revision Received: 07 Feb 2000 Accepted: 09 Feb 2000 First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation E. Anderson, S. Harrison, D.G. Passmore, T.M. Mighall; Holocene alluvial-fan development in the Macgillycuddy's Reeks, southwest Ireland. GSA Bulletin 2000;; 112 (12): 1834–1849. doi: https://doi.org/10.1130/0016-7606(2000)112<1834:HAFDIT>2.0.CO;2 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 SocietyGSA Bulletin Search Advanced Search Abstract Holocene alluvial landforms in the Macgillycuddy's Reeks, southwest Ireland, were investigated to determine the controls and timing of postglacial geomorphic activity. Detailed geomorphologic analysis of three alluvial-fan and debris cones within high-level cirque basins demonstrates evidence of episodic phases of late Holocene surface aggradation and incision. Radiocarbon dates from peat horizons above and below inorganic units show that phases of aggradation cluster into two distinct periods, the first after 230–790 calibrated (cal.) yr A.D. and the second from 1510 cal. yr A.D. to the present. An additional phase of fan aggradation at one site is dated after 1040–1280 cal. yr A.D. All three phases coincide with episodes of enhanced late Holocene valley-floor alluviation and debris-flow activity from upland Britain. Alluvial fans and debris cones have developed primarily as a result of the resedimentation of late Midlandian (Wisconsin) drift and talus slopes, and mobilization of materials involved flooding, transitional-flow, and debris-flow processes. Pollen analysis of peat horizons interbedded with alluvial-fan and debris-cone sediments indicates that land-use changes were an important factor in lowering the threshold for local slope erosion. Phases of aggradation also coincide with well-documented episodes of climate change, and, hence, fan development is probably a function of both anthropogenic and climatic forcing. A sequence of events may have involved initial slope destabilization due to overgrazing and removal of vegetation that was followed by debris mobilization and fan aggradation during intense rainstorms associated with climate change. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.