Lower Proterozoic glaciogenic deposits, eastern Finland

Abstract

Research Article| September 01, 1984 Lower Proterozoic glaciogenic deposits, eastern Finland JUKKA S. MARMO; JUKKA S. MARMO 1Geological Survey of Finland, 02150 Espoo 15, Finland Search for other works by this author on: GSW Google Scholar RICHARD W. OJAKANGAS RICHARD W. OJAKANGAS 2Department of Geology, University of Minnesota, Duluth, Minnesota 55812 Search for other works by this author on: GSW Google Scholar Author and Article Information JUKKA S. MARMO 1Geological Survey of Finland, 02150 Espoo 15, Finland RICHARD W. OJAKANGAS 2Department of Geology, University of Minnesota, Duluth, Minnesota 55812 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1984) 95 (9): 1055–1062. https://doi.org/10.1130/0016-7606(1984)95<1055:LPGDEF>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation JUKKA S. MARMO, RICHARD W. OJAKANGAS; Lower Proterozoic glaciogenic deposits, eastern Finland. GSA Bulletin 1984;; 95 (9): 1055–1062. doi: https://doi.org/10.1130/0016-7606(1984)95<1055:LPGDEF>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 In the lower Proterozoic Sariolian Group of eastern Finland, the metasedimentary Urkkavaara Formation possesses the attributes of a glaciogenic deposit. Within the formation, four members have been established—a lower siltstone-argillite member, a graded sandstone member, an upper siltstone-argillite member, and a diamictite member. The lowest three members contain lonestones. The upper siltstone-argillite member passes gradually over 1 m into a massive diamictite.Many lonestones in the siltstone-argillite members are clearly dropstones. These members, and their association with diamictite, constitute strong evidence for a glaciogenic origin for the formation. The vertical transition of siltstone-argillite into diamictite indicates a similar "raining-down" mechanism of deposition for the diamictite. The thickness of the formation, 30 to 60 m (minimum), suggests deposition from icebergs, rather than from seasonal ice, for the laminated members and the diamictite. The graded sandstone member is interpreted to be a result of turbidity current deposition near a glacial terminus. A glaciomarine environment is suggested.Lonestone-bearing units and diamictites in the Soviet Union just east of Finland have recently been reinterpreted as glaciogenic deposits. There appears, therefore, to have been an early Proterozoic continental glaciation about 2,500 to 2,300 m.y. ago on the Baltic Shield, approximately the same time that early Proterozoic glaciation occurred in North America. 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.