Reduced rapakivi-type granites: The tholeiite connection

Research Article| July 01, 1997 Reduced rapakivi-type granites: The tholeiite connection Carol D. Frost; Carol D. Frost 1Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming 82071 Search for other works by this author on: GSW Google Scholar B. Ronald Frost B. Ronald Frost 1Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming 82071 Search for other works by this author on: GSW Google Scholar Author and Article Information Carol D. Frost 1Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming 82071 B. Ronald Frost 1Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming 82071 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1997) 25 (7): 647–650. https://doi.org/10.1130/0091-7613(1997)0252.3.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 Carol D. Frost, B. Ronald Frost; Reduced rapakivi-type granites: The tholeiite connection. Geology 1997;; 25 (7): 647–650. doi: https://doi.org/10.1130/0091-7613(1997)0252.3.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 SocietyGeology Search Advanced Search Abstract Reduced rapakivi-type granites are the most iron enriched and reduced (i.e., least oxidized) of the "anorogenic" granite association. The low oxygen fugacity and chemical composition of these granites severely limit their sources. In this paper we argue that reduced rapakivi-type granites and their eruptive equivalents, high-potassium fayalite rhyolites, are derived from mafic sources, because tholeiitic magmas and their derivatives have the required low oxygen fugacity. Reduced, rapakivi-type granites are produced either by extreme differentiation of basaltic melts or by partial melting of underplated basalts and their differentiated equivalents. They form in extensional environments where the asthenosphere is present at shallow depths. We envision three stages in the origin of these rocks: (1) tholeiitic melts are emplaced at the base of the crust, (2) continued introduction of heat partially remelts these tholeiitic rocks, and (3) the hot, dry melts so produced migrate into the middle crust to produce rapakivi batholiths or erupt as rhyolites. Partial melting of felsic continental crust may accompany the intrusion of rapakivi-type magmas, thereby producing the other metaluminous and peraluminous granite compositions of the anorogenic suite. 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.