Morphology and structure of a distal submarine trunk channel: The Northwest Atlantic Mid-Ocean Channel between lat 53°N and 44°30′N

Research Article| January 01, 1998 Morphology and structure of a distal submarine trunk channel: The Northwest Atlantic Mid-Ocean Channel between lat 53°N and 44°30′N Ingo Klaucke; Ingo Klaucke 1Department of Earth and Planetary Sciences, McGill University, 3450 University Street, Montreal, Québec H3A 2A7, Canada Search for other works by this author on: GSW Google Scholar Reinhard Hesse; Reinhard Hesse 1Department of Earth and Planetary Sciences, McGill University, 3450 University Street, Montreal, Québec H3A 2A7, Canada Search for other works by this author on: GSW Google Scholar William B. F. Ryan William B. F. Ryan 2Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964 Search for other works by this author on: GSW Google Scholar Author and Article Information Ingo Klaucke 1Department of Earth and Planetary Sciences, McGill University, 3450 University Street, Montreal, Québec H3A 2A7, Canada Reinhard Hesse 1Department of Earth and Planetary Sciences, McGill University, 3450 University Street, Montreal, Québec H3A 2A7, Canada William B. F. Ryan 2Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1998) 110 (1): 22–34. https://doi.org/10.1130/0016-7606(1998)110<0022:MASOAD>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 Email Permissions Search Site Citation Ingo Klaucke, Reinhard Hesse, William B. F. Ryan; Morphology and structure of a distal submarine trunk channel: The Northwest Atlantic Mid-Ocean Channel between lat 53°N and 44°30′N. GSA Bulletin 1998;; 110 (1): 22–34. doi: https://doi.org/10.1130/0016-7606(1998)110<0022:MASOAD>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 Side-scan sonar and seismic data from the hitherto little-known middle to lower reaches of the giant, north-south–extending Northwest Atlantic Mid-Ocean Channel (NAMOC) between lat 53° and 44°30′N reveal a low- to medium-sinuosity and partly straight channel, the course of which is increasingly basement-controlled toward south. Flow restriction by seamounts locally narrowing the channel in the south caused talweg incision by as much as 80 m below the channel floor. Asymmetric levees, resulting from southward-flowing turbidity currents spilling over the channel walls by a mechanism of continuous flow stripping, are remarkably consistent; there is a 30 to 60 m higher western levee, reflecting the effectiveness of the Coriolis force at mid-latitudes. The levees rise 10 to 30 m above the adjacent ocean floor. Consistently lower seismic penetration and more closely spaced reflectors on 3.5 kHz profiles and higher reflectivity on sleeve-gun profiles indicate a higher proportion of sand in the eastern levee. Wash-over fans on the levees formed at sharp channel bends, where deeper, coarser portions of the flows spilled out. Major portions of the turbidity currents that mostly originated off Hudson Strait, however, passed this intermediate channel segment without sedimentation. The down-channel decrease in the difference in height between the western and eastern levees, channel cross-sectional area, and levee height indicate a possible influence of the decrease in the effect of the Coriolis force, flow volume, and/or current speed; separation of the effects of individual variables, however, is currently not possible. 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.