Upper Pleistocene turbidite sand beds and chaotic silt beds in the channelized, distal, outer-fan lobes of the Mississippi fan

Research Article| August 01, 1992 Upper Pleistocene turbidite sand beds and chaotic silt beds in the channelized, distal, outer-fan lobes of the Mississippi fan C. Hans Nelson; C. Hans Nelson 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar David C. Twichell; David C. Twichell 2U.S. Geological Survey, Woods Hole, Massachusetts 02543 Search for other works by this author on: GSW Google Scholar William C. Schwab; William C. Schwab 2U.S. Geological Survey, Woods Hole, Massachusetts 02543 Search for other works by this author on: GSW Google Scholar Homa J. Lee; Homa J. Lee 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar Neil H. Kenyon Neil H. Kenyon 3Institute of Oceanographic Sciences, Wormley, Surrey GU8 5UB, England Search for other works by this author on: GSW Google Scholar Author and Article Information C. Hans Nelson 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 David C. Twichell 2U.S. Geological Survey, Woods Hole, Massachusetts 02543 William C. Schwab 2U.S. Geological Survey, Woods Hole, Massachusetts 02543 Homa J. Lee 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Neil H. Kenyon 3Institute of Oceanographic Sciences, Wormley, Surrey GU8 5UB, England Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1992) 20 (8): 693–696. https://doi.org/10.1130/0091-7613(1992)020<0693:UPTSBA>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation C. Hans Nelson, David C. Twichell, William C. Schwab, Homa J. Lee, Neil H. Kenyon; Upper Pleistocene turbidite sand beds and chaotic silt beds in the channelized, distal, outer-fan lobes of the Mississippi fan. Geology 1992;; 20 (8): 693–696. doi: https://doi.org/10.1130/0091-7613(1992)020<0693:UPTSBA>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 SocietyGeology Search Advanced Search Abstract Cores from a Mississippi outer-fan depositional lobe demonstrate that sublobes at the distal edge contain a complex local network of channelized-turbidite beds of graded sand and debris-flow beds of chaotic silt. Off-lobe basin plains lack siliciclastic coarse-grained beds. The basin-plain mud facies exhibit low acoustic backscatter on SeaMARC IA sidescan sonar images, whereas high acoustic backscatter characteristic of the lobe sand and silt facies. The depth of the first sand-silt layer correlates with relative backscatter intensity and stratigraphic age of the distal sublobes (i.e., shallowest sand = highest backscatter and youngest sublobe). The high proportion (>50%) of chaotic silt compared to graded sand in the distal, outer-fan sublobes may be related to the unstable, muddy, canyon-wall source areas of the extensive Mississippi delta-fed basin slope. A predominace of chaotic silt in cores or outcrops from outer-fan lobes thus may predict similar settings for ancient fans. 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.