Sedimentary Facies Patterns and Geologic History of a Holocene Marine Transgression

Research Article| August 01, 1971 Sedimentary Facies Patterns and Geologic History of a Holocene Marine Transgression JOHN C KRAFT JOHN C KRAFT Department of Geology, University of Delaware, Newark, Delaware 1971 Search for other works by this author on: GSW Google Scholar Author and Article Information JOHN C KRAFT Department of Geology, University of Delaware, Newark, Delaware 1971 Publisher: Geological Society of America Received: 17 Aug 1970 Revision Received: 10 Feb 1971 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1971, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1971) 82 (8): 2131–2158. https://doi.org/10.1130/0016-7606(1971)822131:SFPAGH2.0.CO;2 Article history Received: 17 Aug 1970 Revision Received: 10 Feb 1971 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation JOHN C KRAFT; Sedimentary Facies Patterns and Geologic History of a Holocene Marine Transgression. GSA Bulletin 1971;; 82 (8): 2131–2158. doi: https://doi.org/10.1130/0016-7606(1971)822131:SFPAGH2.0.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 Studies of Holocene sediments in coastal Delaware show complex sediment distribution patterns resulting from lateral and vertical movement of successive environments of deposition over a Pleistocene unconformity. These sediments are infilling a drowned topography with a local relief of 70 ft and possibly up to 125 ft eroded on highly variable Pleistocene sediments. Identification of the Pleistocene surface remains a problem. However, it may be recognizable at the unconformity as a soil zone or intermixture of firm marsh clay-silts with Pleistocene sands, as well as on the basis of radiocarbon dates.Larger depositional features forming around eroding Pleistocene headlands and infilling the estuaries include characteristic shoreline environments, such as spits, dunes, baymouth barriers, an intermeshing network of tidal deltas, nearshore marine erosional-depositional sands and gravels, and lagoons or estuaries with fringing Spartina, Distichlis, and Phragmites marshes, which form the westernmost edge of the transgressive units. The thickness and areal extent of the sedimentary bodies are to a large degree controlled by the morphology of the Pleistocene unconformity. A large portion of the Holocene sedimentary units is being eroded by the transgressing Atlantic Ocean.Cores of sediment under the shallow lagoons, such as Rehoboth, Indian River, and Assawoman Bays, and in the fringing marsh environment, show that the depositional units are thin, highly irregular in areal extent, extremely variable in thickness, and difficult to project. Sedimentary processes active in the shallow bays include shoreline marsh erosion and the formation of thin, possibly ephemeral, beach-dune washover complexes consisting of clean, well-sorted sand, with typical beach and washover sedimentary structures. These wash-over beaches are an anomaly completely surrounded by Spartina marshes on the landward side and extremely muddy sands grading into dark gray lagoonal muds on the bay side. It appears that distinctive sedimentary structures and sediment size-sorting relationships, such as those that characterize the larger, more common sedimentary units of the coastal area, may be formed in miniature at the very thin edge of transgression and may lead to considerable confusion in the interpretation of sediments of this type in the geologic record. 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.