Granitic ring complexes and Precambrian hot-spot activity in the St. Francois terrane, Midcontinent region, United States

Abstract

Research Article| January 01, 1980 Granitic ring complexes and Precambrian hot-spot activity in the St. Francois terrane, Midcontinent region, United States Eva B. Kisvarsanyi Eva B. Kisvarsanyi 1Missouri Department of Natural Resources, Geological Survey, Rolla, Missouri 65401 Search for other works by this author on: GSW Google Scholar Author and Article Information Eva B. Kisvarsanyi 1Missouri Department of Natural Resources, Geological Survey, Rolla, Missouri 65401 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1980) 8 (1): 43–47. https://doi.org/10.1130/0091-7613(1980)8<43:GRCAPH>2.0.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Eva B. Kisvarsanyi; Granitic ring complexes and Precambrian hot-spot activity in the St. Francois terrane, Midcontinent region, United States. Geology 1980;; 8 (1): 43–47. doi: https://doi.org/10.1130/0091-7613(1980)8<43:GRCAPH>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 SocietyGeology Search Advanced Search Abstract Surface and subsurface geologic data have led to the recognition of granitic ring complexes in the 1.5-b.y.-old St. Francois terrane of southeastern Missouri. The distinctive rock association of the ring complexes comprises alkaline silicic rocks with minor quartz monzonite, trachyte, and basalt. Three periods of granite emplacement are recognized: sub-volcanic granite massifs were emplaced below comagmatic rhyolites and ash-flow tuffs, quartz monzonite and associated hypabyssal rocks were intruded along ring fractures in cauldron-subsidence structures, and central plutons were emplaced in resurgent cauldrons. Similar magmatic complexes in the buried Precambrian basement of the Midcontinent indicate a period of widespread anorogenic magmatism that may have been induced by intraplate hot-spot activity. The post-Precambrian geologic record of the region suggests that recurrent, but localized and less intense, hot-spot activity was responsible for emplacements of alkaline ultramafic rocks, for tectonic adjustments, and for increased geothermal gradients that created favorable ore-concentrating environments in the sedimentary rocks. 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.