Fluvial evolution of the lower Mississippi River valley during the last 100 k.y. glacial cycle: Response to glaciation and sea-level change

Abstract

Research Article| May 01, 2007 Fluvial evolution of the lower Mississippi River valley during the last 100 k.y. glacial cycle: Response to glaciation and sea-level change Tammy M. Rittenour; Tammy M. Rittenour 1Department of Geosciences, University of Nebraska, Lincoln, 214 Bessey Hall, Lincoln, Nebraska 68588-0340, USA Search for other works by this author on: GSW Google Scholar Michael D. Blum; Michael D. Blum 2Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803, USA Search for other works by this author on: GSW Google Scholar Ronald J. Goble Ronald J. Goble 3Department of Geosciences, University of Nebraska, Lincoln, 214 Bessey Hall, Lincoln, Nebraska 68588-0340, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Tammy M. Rittenour 1Department of Geosciences, University of Nebraska, Lincoln, 214 Bessey Hall, Lincoln, Nebraska 68588-0340, USA Michael D. Blum 2Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803, USA Ronald J. Goble 3Department of Geosciences, University of Nebraska, Lincoln, 214 Bessey Hall, Lincoln, Nebraska 68588-0340, USA Publisher: Geological Society of America Received: 17 Nov 2005 Revision Received: 20 Nov 2006 Accepted: 18 Dec 2006 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 GEOLOGICAL SOCIETY OF AMERICA GSA Bulletin (2007) 119 (5-6): 586–608. https://doi.org/10.1130/B25934.1 Article history Received: 17 Nov 2005 Revision Received: 20 Nov 2006 Accepted: 18 Dec 2006 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Tammy M. Rittenour, Michael D. Blum, Ronald J. Goble; Fluvial evolution of the lower Mississippi River valley during the last 100 k.y. glacial cycle: Response to glaciation and sea-level change. GSA Bulletin 2007;; 119 (5-6): 586–608. doi: https://doi.org/10.1130/B25934.1 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 The lower Mississippi valley contains multiple large braid belts for which age control has been limited. Application of the optically stimulated luminescence technique has produced a new chronology of lower Mississippi valley channel-belt formation and insight into the valley's evolution during the last glacial cycle. Fluvial deposits range from last interglacial meander belts (85 ± 7 to 83 ± 7 ka) to multiple braid belts (64 ± 5 to 11 ± 1 ka) and record large-amplitude responses of the Mississippi River to glacially induced changes in discharge and sediment supply during the last glacial cycle. Slackwater deposits in buried tributary valleys from the middle Mississippi valley and northern lower Mississippi valley suggest that the river was flowing at a position 8–21 m below the present flood plain during the last interglacial, then rapidly aggraded and switched to a braided regime to form the highest and oldest braid belt by 64 ± 5 to 50 ± 4 ka, coincident with initial glaciation of the upper drainage basin. The Mississippi River remained braided until final meltwater withdrawal from its headwaters in the earliest Holocene. Braid-belt formation and incision was controlled by fluctuations in meltwater and sediment discharge, while glacio-eustatic sea level controlled the elevation to which the river was graded, causing late glacial braid belts to dip below the Holocene flood plain in the southern lower Mississippi valley. Moreover, avulsions in the middle Mississippi valley and northern lower Mississippi valley during the last glaciation have pinned the river over regions of shallow bedrock, preventing the modern river from incising to its last interglacial profile. The new chronology and longitudinal profiles presented here provide insight into the response of this continental-scale river system to climatic (glacial) and base-level forcing during the last 100 k.y. glacial cycle. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.