LITHOFACIES OF THE SALT WASH MEMBER OF THE MORRISON FORMATION, COLORADO PLATEAU

Research Article| April 01, 1957 LITHOFACIES OF THE SALT WASH MEMBER OF THE MORRISON FORMATION, COLORADO PLATEAU THOMAS E MULLENS; THOMAS E MULLENS U. S. GEOLOGICAL SURVEY, GRAND JUNCTION, COLORADO Search for other works by this author on: GSW Google Scholar VAL L FREEMAN VAL L FREEMAN U. S. GEOLOGICAL SURVEY, GRAND JUNCTION, COLORADO Search for other works by this author on: GSW Google Scholar Author and Article Information THOMAS E MULLENS U. S. GEOLOGICAL SURVEY, GRAND JUNCTION, COLORADO VAL L FREEMAN U. S. GEOLOGICAL SURVEY, GRAND JUNCTION, COLORADO Publisher: Geological Society of America Received: 28 Nov 1955 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1957, 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 (1957) 68 (4): 505–526. https://doi.org/10.1130/0016-7606(1957)68[505:LOTSWM]2.0.CO;2 Article history Received: 28 Nov 1955 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 THOMAS E MULLENS, VAL L FREEMAN; LITHOFACIES OF THE SALT WASH MEMBER OF THE MORRISON FORMATION, COLORADO PLATEAU. GSA Bulletin 1957;; 68 (4): 505–526. doi: https://doi.org/10.1130/0016-7606(1957)68[505:LOTSWM]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 SocietyGSA Bulletin Search Advanced Search Abstract The Salt Wash is the basal member of the Upper Jurassic Morrison Formation in parts of Utah, Colorado, Arizona, and New Mexico. Deposited by streams, it comprises lenticular beds of cross-laminated sandstone irregularly interbedded with mudstone, siltstone, claystone, and horizontally laminated sandstone.The term "lithofacies," as used in this paper, denotes lithologic aspect. The specific lithofacies of the Salt Wash member at a given locality is determined by the thickness, proportion, and continuity of the stream and flood-plain deposits that make up the Salt Wash. Stream deposits include all rocks interpreted as deposited from moving water; flood-plain deposits include all rocks interpreted as deposited from slack water.Regional differences in lithofacies show that the Salt Wash member is a fan-shaped wedge of sedimentary rocks whose apex is in south-central Utah. Within the wedge, the thickness of the Salt Wash and the thickness, proportion, and continuity of the contained stream deposits decrease relatively uniformly to the north, northeast, and southeast of the apex.Interpretation of the regional differences in lithofacies indicates deposition by a distributary stream system whose apex was in south-central Utah and which spread sediments to the north, east, and southeast over a nearly flat plain. Irregularities on this plain near the Four Corners area and in west-central Colorado modified the distributary system, and therefore the wedge is not symmetrical.Most uranium-vanadium ore deposits in the Salt Wash member occur in a lithofacies near the center of the wedge. This may be a genetic relation and can be explained as a function of transmissibility of the particular lithofacies. The ore deposits, however, are concentrated in a relatively small part of the central lithofacies. Because local geologic features such as structure or igneous intrusions might control the localization of ore deposits in the small area, the high degree of correlation of ore deposits and a certain lithofacies may be coincidental. This content is PDF only. Please click on the PDF icon to access. 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.