Conversion of diatoms to clays during early diagenesis in tropical, continental shelf muds

Research Article| December 01, 2000 Conversion of diatoms to clays during early diagenesis in tropical, continental shelf muds Panagiotis Michalopoulos; Panagiotis Michalopoulos 1Marine Sciences Research Center, State University of New York, Stony Brook, New York 11794-5000, USA Search for other works by this author on: GSW Google Scholar Robert C. Aller; Robert C. Aller 1Marine Sciences Research Center, State University of New York, Stony Brook, New York 11794-5000, USA Search for other works by this author on: GSW Google Scholar Richard J. Reeder Richard J. Reeder 2Department of Geosciences, State University of New York, Stony Brook, New York 11794, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Panagiotis Michalopoulos 1Marine Sciences Research Center, State University of New York, Stony Brook, New York 11794-5000, USA Robert C. Aller 1Marine Sciences Research Center, State University of New York, Stony Brook, New York 11794-5000, USA Richard J. Reeder 2Department of Geosciences, State University of New York, Stony Brook, New York 11794, USA Publisher: Geological Society of America Received: 25 Apr 2000 Revision Received: 11 Sep 2000 Accepted: 14 Sep 2000 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2000) 28 (12): 1095–1098. https://doi.org/10.1130/0091-7613(2000)28<1095:CODTCD>2.0.CO;2 Article history Received: 25 Apr 2000 Revision Received: 11 Sep 2000 Accepted: 14 Sep 2000 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Panagiotis Michalopoulos, Robert C. Aller, Richard J. Reeder; Conversion of diatoms to clays during early diagenesis in tropical, continental shelf muds. Geology 2000;; 28 (12): 1095–1098. doi: https://doi.org/10.1130/0091-7613(2000)28<1095:CODTCD>2.0.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 SocietyGeology Search Advanced Search Abstract In coastal muds downdrift from the Amazon River mouth, marine diatom frustules are rapidly converted to various forms of authigenic aluminosilicate phases during burial. The dominant neoformed crystalline phases have a composition similar to K-smectite, yield electron diffraction patterns characteristic of clay minerals, and exhibit a range of crystal sizes and morphologies, including euhedral pseudohexagonal crystals and anhedral flakes replacing biogenic silica. A poorly crystalline or microcrystalline K-rich and Fe-rich aluminosilicate material also replaces the siliceous frustules. The conversion process is not always complete, leaving relics of the original frustule in the resulting authigenic aluminosilicate phases. Laboratory incubation experiments with cultured diatoms demonstrate that the conversion process occurs in 20–23 months. The conversion of biogenic silica to authigenic clays occurs throughout the Amazon deltaic deposits and presumably takes place in other comparable depositional settings. Biogenic silica alteration provides proof for a direct link between the biogeochemical cycle of silica in nearshore environments and the neoformation of cation-rich aluminosilicate phases, and it may prove to be important for oceanic geochemical cycles as a sink for Si, K, and other elements incorporated in the authigenic aluminosilicates. Rapid formation of authigenic K-smectite may also represent a reaction stage leading to eventual formation of illitic clays during later diagenesis. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.