Marine sedimentation at a calving glacier margin

Research Article| May 01, 2000 Marine sedimentation at a calving glacier margin Gail M. Ashley; Gail M. Ashley 1Department of Geological Sciences, Rutgers University, New Brunswick, New Jersey 08903, USA Search for other works by this author on: GSW Google Scholar Norman D. Smith Norman D. Smith 2Department of Geosciences, University of Nebraska, Lincoln, Nebraska 68588-0340, USA Search for other works by this author on: GSW Google Scholar GSA Bulletin (2000) 112 (5): 657–667. https://doi.org/10.1130/0016-7606(2000)112<657:MSAACG>2.0.CO;2 Article history received: 27 Jun 1996 rev-recd: 08 Jun 1999 accepted: 12 Aug 1999 first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Gail M. Ashley, Norman D. Smith; Marine sedimentation at a calving glacier margin. GSA Bulletin 2000;; 112 (5): 657–667. doi: https://doi.org/10.1130/0016-7606(2000)112<657:MSAACG>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract A 2-month study at a subpolar, tidewater glacier was conducted at Anvers Island, Antarctic Peninsula (lat 64°S), to improve understanding of sedimentary processes and associated deposits in glacial marine settings. Data collected in the ice-proximal environment were (1) brash ice-size distribution and melt rates to assess sediment source and transport mechanisms; (2) conductivity-temperature-turbidity-depth (CTTD) profiles, water samples, and sediment-trap catches to study processes and patterns of sediment dispersal; (3) bottom cores and grabs to document recent glacial marine sedimentation; and (4) remotely operated vehicle video surveys of the ice terminus and sea bottom to obtain images of physical and biological processes. The water column is stratified and a halocline occurs at ∼20–30 m. Water temperature ranged from −1 to 1.6 °C, salinity was 32‰–34‰, and suspended solids were 3–5 mg/l well above the bottom. Ephemeral turbid horizons contain 8–15 mg/l suspended solids; rare surface plumes and a quasipermanent turbid layer produced by resuspension during calving events reach 25–35 mg/l. Meltwater drains from the glacier surface, but no subglacial meltwater was detected directly entering the sea. The most important sources of sediment appear to be the direct melting of the submerged ice front and melting of calved glacial ice. Most fragments of floating ice melt within 1 km of the ice front. Some sediment may be contributed as low-density (1.1 g/cm3) algae-bound sediment pellets by meltwater streams draining the ablating ice surface. Sediment enters the stratified water column and is moved by tidal and wind-driven circulation. Marine sedimentation rates are low (∼3 mm/yr) relative to depth of bioturbation, resulting in unstratified sandy mud with dispersed clasts. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.