Deposition of the uppermost Cambrian (Croixan) Jordan Sandstone, and the nature of the Cambrian-Ordovician boundary in the Upper Mississippi Valley

Research Article| April 01, 1994 Deposition of the uppermost Cambrian (Croixan) Jordan Sandstone, and the nature of the Cambrian-Ordovician boundary in the Upper Mississippi Valley ANTHONY C. RUNKEL ANTHONY C. RUNKEL 1Minnesota Geological Survey, 2642 University Avenue, St. Paul, Minnesota 55114-1057 Search for other works by this author on: GSW Google Scholar Author and Article Information ANTHONY C. RUNKEL 1Minnesota Geological Survey, 2642 University Avenue, St. Paul, Minnesota 55114-1057 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1994) 106 (4): 492–506. https://doi.org/10.1130/0016-7606(1994)106<0492:DOTUCC>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation ANTHONY C. RUNKEL; Deposition of the uppermost Cambrian (Croixan) Jordan Sandstone, and the nature of the Cambrian-Ordovician boundary in the Upper Mississippi Valley. GSA Bulletin 1994;; 106 (4): 492–506. doi: https://doi.org/10.1130/0016-7606(1994)106<0492:DOTUCC>2.3.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 The Jordan Sandstone, of Late Cambrian (Croixan) age, is well known as one of several cratonic sheet sandstones in the Upper Mississippi Valley that are part of the classic Paleozoic "orthoquartzite-carbonate suite". Evidence that the Jordan is an entirely marine, regressive sequence, rather than transgressive as commonly assumed, provides new insight into the origin of cratonic sheet sandstones.The lower half of the Jordan Sandstone is composed of two intercalated lithofacies: (1) extensively burrowed, very fine grained sand-stone interbedded with hummocky cross-stratified beds deposited on the offshore shelf and (2) fine-grained, burrowed, cross-stratified sandstone deposited on the lower shoreface during storms. The upper half of the Jordan consists of medium- to coarse-grained sand-stone deposited on the upper shoreface by tidal and storm-generated currents. This lithofacies is characterized by abundant scour surfaces, tidal inlet fills, and very large angular intra-clasts of sandstone derived from incised beach-rock on the foreshore.Lithofacies associations demonstrate that the Jordan Sandstone is a regressive sequence deposited as part of a shoreline system that prograded across the Hollandale embayment, a shallow depression on the cratonic shelf in the Upper Mississippi Valley region. Progradation was interrupted by transgressive episodes recorded as local tongues of offshore deposits that disconformably overlie shoreface deposits. This sedimentologic model contributes to the evaluation of depositional controls in Late Cambrian time, and to solving some long-standing enigmas associated with cratonic sheet sandstones.Contrary to the long-held view that the Cambrian-Ordovician boundary is conformable in this region, sedimentologic evidence indicates that a regional unconformity separates the Jordan Sandstone from the Early Ordovician Oneota Dolomite. Deep incision into the lowest Jordan lithofacies occurred near the Transcontinental Arch on the western margin of the embayment, and near the Wisconsin Arch on the eastern margin. This differential erosion marks the earliest known tectonic up-lift of the basin's margins relative to the center. 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.