Facies architecture and grounding-line fan processes of morainal banks during the deglaciation of Coastal Maine

Research Article| August 01, 1996 Facies architecture and grounding-line fan processes of morainal banks during the deglaciation of Coastal Maine Lewis E. Hunter; Lewis E. Hunter 1U.S. Army Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire 03755 Search for other works by this author on: GSW Google Scholar Ross D. Powell; Ross D. Powell 2Department of Geology, Northern Illinois University, DeKalb, Illinois 60115 Search for other works by this author on: GSW Google Scholar Geoffrey W. Smith Geoffrey W. Smith 3Department of Geology, Ohio University, Athens, Ohio 45701 Search for other works by this author on: GSW Google Scholar Author and Article Information Lewis E. Hunter 1U.S. Army Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire 03755 Ross D. Powell 2Department of Geology, Northern Illinois University, DeKalb, Illinois 60115 Geoffrey W. Smith 3Department of Geology, Ohio University, Athens, Ohio 45701 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1996) 108 (8): 1022–1038. https://doi.org/10.1130/0016-7606(1996)108<1022:FAAGLF>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Lewis E. Hunter, Ross D. Powell, Geoffrey W. Smith; Facies architecture and grounding-line fan processes of morainal banks during the deglaciation of Coastal Maine. GSA Bulletin 1996;; 108 (8): 1022–1038. doi: https://doi.org/10.1130/0016-7606(1996)108<1022:FAAGLF>2.3.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 Submarine jet processes are inferred from glaciomarine facies exposed in gravel pits in southwestern coastal Maine. The geometry and distribution of fan facies depend on (1) the proximity to the grounding line and stream effluxes, (2) the angle of jet trajectory from glacier conduits, and (3) sediment remobilization processes. Syndepositional glaciotectonic deformation further augments morainal bank formation through pushing and squeezing of fan sediments at the grounding line.Complex process-sediment interactions along the temperate tidewater margin of the Laurentide ice sheet are recorded in the facies architecture of sedimentary sequences in morainal banks. Morainal bank accumulation was governed by rapid fluvial deposition, and outwash jet dynamics that controlled the spatial distribution of sedimentary facies. Near the grounding line, meltwater dynamics change rapidly where sediment-laden fresh water is discharged at or near the sea floor. Turbulent mixing with ambient sea water and discharge fluctuations cause rapid changes in flow competence, accompanied by the dumping of bed-load gravel and sand at the apices of grounding-line fans in the morainal banks.Jet trajectory relative to the morainal-bank slope determines whether a jet will make contact with the morainal bank. Gravel and sand remain in bed-load traction as long as the jet is in contact with the morainal bank. Bed-load dumping and settling of the coarse suspended load occurs where buoyant forces in the jet overcome momentum forces or where the jet is deflected by the morainal bank. Below these buoyant jets, backflow eddies can produce currents that drive ripple migration toward the grounding line. Abrupt facies changes record fluctuations in jet discharge and trajectory and sediment redistribution by sediment gravity flows initiated near the grounding line. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.