Assessing subglacial processes from diatom fragmentation patterns

Abstract

Research Article| July 01, 2004 Assessing subglacial processes from diatom fragmentation patterns Reed P. Scherer; Reed P. Scherer 1Geology and Environmental Geosciences, Northern Illinois University, DeKalb, Illinois 60115, USA Search for other works by this author on: GSW Google Scholar Charlotte M. Sjunneskog; Charlotte M. Sjunneskog 1Geology and Environmental Geosciences, Northern Illinois University, DeKalb, Illinois 60115, USA Search for other works by this author on: GSW Google Scholar Neal R. Iverson; Neal R. Iverson 2Geological and Atmospheric Sciences, Iowa State University, Ames, Iowa 50011, USA Search for other works by this author on: GSW Google Scholar Thomas S. Hooyer Thomas S. Hooyer 3Wisconsin Geological Survey, University of Wisconsin, Madison, Wisconsin 53705, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Reed P. Scherer 1Geology and Environmental Geosciences, Northern Illinois University, DeKalb, Illinois 60115, USA Charlotte M. Sjunneskog 1Geology and Environmental Geosciences, Northern Illinois University, DeKalb, Illinois 60115, USA Neal R. Iverson 2Geological and Atmospheric Sciences, Iowa State University, Ames, Iowa 50011, USA Thomas S. Hooyer 3Wisconsin Geological Survey, University of Wisconsin, Madison, Wisconsin 53705, USA Publisher: Geological Society of America Received: 18 Dec 2003 Revision Received: 15 Mar 2004 Accepted: 22 Mar 2004 First Online: 02 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2004) 32 (7): 557–560. https://doi.org/10.1130/G20423.1 Article history Received: 18 Dec 2003 Revision Received: 15 Mar 2004 Accepted: 22 Mar 2004 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Reed P. Scherer, Charlotte M. Sjunneskog, Neal R. Iverson, Thomas S. Hooyer; Assessing subglacial processes from diatom fragmentation patterns. Geology 2004;; 32 (7): 557–560. doi: https://doi.org/10.1130/G20423.1 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 SocietyGeology Search Advanced Search Abstract Reconstructing the size and glacial style of past ice-sheet advances requires interpreting complex glacial sedimentary facies. We use diatoms, a major component of Antarctic continental shelf deposits, to infer the physical conditions under which these deposits were emplaced. The degree of diatom fragmentation and the presence of diatoms of varying stratigraphic age in glacial sediments provide means to qualitatively gauge glacial mixing and transport. Here we report an experimentally calibrated index of diatom fragmentation that provides a simple but objective method of assessing the degree of subshearing imparted on marine glacial sedimentary deposits. By using a ring-shear device to subject diatomaceous sediment to stresses comparable to those beneath the Ross ice streams, we quantitatively assess patterns of diatom comminution resulting from compaction and from progressive shear stress. Elongate pennate diatoms are found to break disproportionately to discoid centric diatoms when subjected to shear stress; thus, a simple ratio of unbroken centric to pennate diatoms provides a reliable gauge of past shearing. Comparison of ring-shear results with a suite of previously analyzed sediments that represent a variety of glacial, glacial-marine, and hemipelagic settings of the Ross Sea and subglacial Ross Embayment demonstrates that this index can be employed for estimating relative subglacial stresses in this setting. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.