Ecosystem Structure and Stability: Middle Upper Ordovician of Central Kentucky, USA

Other| August 01, 2004 Ecosystem Structure and Stability: Middle Upper Ordovician of Central Kentucky, USA STEVEN M. HOLLAND; STEVEN M. HOLLAND 1Department of Geology, University of Georgia, Athens, GA 30602-2501, stratum@gly.uga.edu Search for other works by this author on: GSW Google Scholar MARK E. PATZKOWSKY MARK E. PATZKOWSKY 2Department of Geosciences, Pennsylvania State University, University Park, PA 16802-2714 Search for other works by this author on: GSW Google Scholar Author and Article Information STEVEN M. HOLLAND 1Department of Geology, University of Georgia, Athens, GA 30602-2501, stratum@gly.uga.edu MARK E. PATZKOWSKY 2Department of Geosciences, Pennsylvania State University, University Park, PA 16802-2714 Publisher: SEPM Society for Sedimentary Geology Accepted: 09 Feb 2004 First Online: 03 Mar 2017 Online ISSN: 1938-5323 Print ISSN: 0883-1351 Society for Sedimentary Geology PALAIOS (2004) 19 (4): 316–331. https://doi.org/10.1669/0883-1351(2004)019<0316:ESASMU>2.0.CO;2 Article history Accepted: 09 Feb 2004 First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation STEVEN M. HOLLAND, MARK E. PATZKOWSKY; Ecosystem Structure and Stability: Middle Upper Ordovician of Central Kentucky, USA. PALAIOS 2004;; 19 (4): 316–331. doi: https://doi.org/10.1669/0883-1351(2004)019<0316:ESASMU>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 SocietyPALAIOS Search Advanced Search Abstract Cluster analysis reveals eight biofacies during a time of faunal turnover and regional oceanographic change in the middle Upper Ordovician of central Kentucky. These biofacies are arranged along a deep-water to shallow-water gradient, with the dalmanellid and the Sowerbyella biofacies in offshore facies, the Rafinesquina, the atrypid, and the ramose trepostome biofacies in deep-subtidal to shallow-subtidal facies, the Constellaria-Cyclonema and the Rhynchotrema biofacies in the shallow-subtidal facies, and the Solenopora-Hebertella biofacies in sand-shoal facies. These biofacies are not discrete, but rather they share a large number of taxa suggesting that they are arbitrary subdivisions of a depth-related ecological gradient. Nonetheless, they are useful as a point of comparison with other studies of this time interval in the eastern United States. Previous lower and middle Upper Ordovician biofacies studies portray a similar pattern of plectorthines and rhynchonellaceans in the shallow subtidal, strophomenids in the deep subtidal, and dalmanellids and plectambonitaceans in the offshore, indicating an overall temporal consistency to many of these biofacies at suprageneric taxonomic levels. Similarly, values of preferred depth, depth tolerance, and peak abundance of most taxa are generally conserved, and this is particularly true for abundant taxa. Nonetheless, this 2-m.y. record also indicates temporal changes in the occurrence of some biofacies, in the relative abundances of taxa in some biofacies, in the species membership within biofacies, and in values of preferred depth, depth tolerance, and peak abundance for several taxa. Collectively these indicate a dynamic aspect to an ecosystem that otherwise displays several attributes of stability and underscore that ecologic stability should not be viewed as a simple dichotomy between stability and instability. The dynamic aspects of this ecosystem suggest that these biofacies were not governed by extreme degrees of species interactions that resulted in near constancy of biofacies structure. Continuous changes in water temperature, nutrient supply, and turbidity during this time may have been a contributing factor to changes within this ecosystem. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.