Fjords as temporary sediment traps: History of glacial erosion and deposition in Muir Inlet, Glacier Bay National Park, southeastern Alaska

Research Article| July 01, 2010 Fjords as temporary sediment traps: History of glacial erosion and deposition in Muir Inlet, Glacier Bay National Park, southeastern Alaska Ellen A. Cowan; Ellen A. Cowan † 1Department of Geology, Appalachian State University, Box 32067, Boone, North Carolina 28608, USA †E-mail: cowanea@appstate.edu Search for other works by this author on: GSW Google Scholar Keith C. Seramur; Keith C. Seramur 1Department of Geology, Appalachian State University, Box 32067, Boone, North Carolina 28608, USA Search for other works by this author on: GSW Google Scholar Ross D. Powell; Ross D. Powell 2Department of Geology and Environmental Sciences, and Analytical Center for Climate and Environmental Change, Northern Illinois University, DeKalb, Illinois 60115, USA Search for other works by this author on: GSW Google Scholar Bryce A. Willems; Bryce A. Willems * 2Department of Geology and Environmental Sciences, and Analytical Center for Climate and Environmental Change, Northern Illinois University, DeKalb, Illinois 60115, USA *Current address: Department of Geological Sciences, University of Alaska Anchorage, 3211 Providence Drive, Anchorage, Alaska 99508, USA. Search for other works by this author on: GSW Google Scholar Sean P.S. Gulick; Sean P.S. Gulick 3Institute for Geophysics, University of Texas at Austin, J.J. Pickle Research Campus, Austin, Texas 78758, USA Search for other works by this author on: GSW Google Scholar John M. Jaeger John M. Jaeger 4Department of Geological Sciences, University of Florida, P.O. Box 112120, Gainesville, Florida 32611, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Ellen A. Cowan † 1Department of Geology, Appalachian State University, Box 32067, Boone, North Carolina 28608, USA Keith C. Seramur 1Department of Geology, Appalachian State University, Box 32067, Boone, North Carolina 28608, USA Ross D. Powell 2Department of Geology and Environmental Sciences, and Analytical Center for Climate and Environmental Change, Northern Illinois University, DeKalb, Illinois 60115, USA Bryce A. Willems * 2Department of Geology and Environmental Sciences, and Analytical Center for Climate and Environmental Change, Northern Illinois University, DeKalb, Illinois 60115, USA Sean P.S. Gulick 3Institute for Geophysics, University of Texas at Austin, J.J. Pickle Research Campus, Austin, Texas 78758, USA John M. Jaeger 4Department of Geological Sciences, University of Florida, P.O. Box 112120, Gainesville, Florida 32611, USA †E-mail: cowanea@appstate.edu *Current address: Department of Geological Sciences, University of Alaska Anchorage, 3211 Providence Drive, Anchorage, Alaska 99508, USA. Publisher: Geological Society of America Received: 11 Dec 2008 Revision Received: 12 Aug 2009 Accepted: 03 Sep 2009 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2010 Geological Society of America GSA Bulletin (2010) 122 (7-8): 1067–1080. https://doi.org/10.1130/B26595.1 Article history Received: 11 Dec 2008 Revision Received: 12 Aug 2009 Accepted: 03 Sep 2009 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Ellen A. Cowan, Keith C. Seramur, Ross D. Powell, Bryce A. Willems, Sean P.S. Gulick, John M. Jaeger; Fjords as temporary sediment traps: History of glacial erosion and deposition in Muir Inlet, Glacier Bay National Park, southeastern Alaska. GSA Bulletin 2010;; 122 (7-8): 1067–1080. doi: https://doi.org/10.1130/B26595.1 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 SocietyGSA Bulletin Search Advanced Search Abstract Glacimarine sedimentary deposits within the basins of Muir Inlet, a 48-km-long silled fjord, are interpreted from complimentary sets of high-resolution, seismic-reflection profiles using known glacial-advance and retreat history. Two prominent glacial erosion surfaces are identified: the lowest attributed to the Last Glacial Maximum (LGM) advance and the upper coincident with the Little Ice Age (LIA) advance. The LGM ice sheet, which advanced onto the continental shelf, was 1700 m thick in Muir Inlet and eroded bedrock, whereas the thinner LIA ice did not. LGM deposits >300 m thick occur beneath the LIA erosion surface in the deepest basins. Evidence for earlier Neoglacial advances is present in subaerial deposits; however, Neoglacial sediments preserved within the marine record are restricted to one depositional package on the entrance sill. Volumes of LIA retreat sediments were calculated within basins. An average annual sediment flux was calculated by modeling the duration of sediment contributed from Muir Glacier and from tributary glaciers and side-entry sources. The annual sediment flux ranged from 1.3 × 106 m3/yr to 4.6 × 107 m3/yr and increases logarithmically with increasing drainage basin area, similar to fluvial systems. This sediment flux does not only represent bedrock erosion. Additional sediment is contributed from persistent tributary glaciers and from LGM sediment stored within deeper basins. Basin-wide reflections characterize the most common seismic facies and indicate that strata are horizontal and continuous across each basin, confirming the importance of sediment gravity flows originating from sills and sloping fjord walls. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.