The Wayah granulite-facies metamorphic core, southwestern North Carolina: High-grade culmination of Taconic metamorphism in the southern Blue Ridge

Abstract

Research Article| November 01, 1989 The Wayah granulite-facies metamorphic core, southwestern North Carolina: High-grade culmination of Taconic metamorphism in the southern Blue Ridge JAMES O. ECKERT, JR.; JAMES O. ECKERT, JR. 1Department of Geology, Texas A&M University, College Station, Texas 77843-3115 Search for other works by this author on: GSW Google Scholar ROBERT D. HATCHER, JR.; ROBERT D. HATCHER, JR. 2Department of Geological Sciences, University of Tennessee, Knoxville, Tennessee 37996-1410 Search for other works by this author on: GSW Google Scholar DAVID W. MOHR DAVID W. MOHR 3Code 2110, Naval Coastal Systems Center, Building 110, Room 3C27, Panama City, Florida 32401-5000 Search for other works by this author on: GSW Google Scholar Author and Article Information JAMES O. ECKERT, JR. 1Department of Geology, Texas A&M University, College Station, Texas 77843-3115 ROBERT D. HATCHER, JR. 2Department of Geological Sciences, University of Tennessee, Knoxville, Tennessee 37996-1410 DAVID W. MOHR 3Code 2110, Naval Coastal Systems Center, Building 110, Room 3C27, Panama City, Florida 32401-5000 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1989) 101 (11): 1434–1447. https://doi.org/10.1130/0016-7606(1989)101<1434:TWGFMC>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 MailTo Tools Icon Tools Get Permissions Search Site Citation JAMES O. ECKERT, ROBERT D. HATCHER, DAVID W. MOHR; The Wayah granulite-facies metamorphic core, southwestern North Carolina: High-grade culmination of Taconic metamorphism in the southern Blue Ridge. GSA Bulletin 1989;; 101 (11): 1434–1447. doi: https://doi.org/10.1130/0016-7606(1989)101<1434:TWGFMC>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 Wayah granulite-facies metamorphic core, in the eastern Blue Ridge, southwestern North Carolina, contains the metamafic assemblage hornblende-orthopyroxene-clinopyroxene which defines the hornblende (lower) granulite facies. The metamorphic progression from the kyanite-almandine zone into the Wayah granulite core is continuous across the Hayesville fault, a major premetamorphic-peak tectonostratigraphic boundary. This metamorphic transition includes a distinct muscovite-absent (+alkali feldspar) second-sillimanite zone. Retrogression is limited. This entire range in metamorphic grade apparently was produced during a single, prograde, Paleozoic (likely Taconic) metamorphic event.The Hayesville fault crosses the study area mostly within the first-sillimanite zone, northwest of the Wayah granulite core. Both supracrustal sequences juxtaposed along this fault consist predominantly of metasedimentary rocks probably deposited during the Late Proterozoic. Although paragneiss pre-dominates, the southeastern terrane is distinguished by the presence of metamorphosed felsic, mafic, and ultramafic igneous rocks. No evidence supports the presence of Grenville basement within the study area.The second of four deformational events, synchronous with the metamorphic peak, created northeast-southwest- to east-west-trending, upright isoclinal folds which dominate the outcrop pattern. Macroscopic F2 folds deformed the Hayesville fault.Application of mineralogic thermometry and barometry yields conditions which range from 585 °C, 5.5 kb at the kyanite-sillimanite isograd to 842 °C, 9.8 kb in the hornblende granulite facies. Macroscopic distributions of migmatite and perthite, published experimental data, and barometric calculations suggest that T = ∼669 °C, P = ∼6.52 kb, and X(H2O) = ∼0.62 at the second-sillimanite isograd.Results indicate that the Wayah granulite-facies core constitutes the high-grade culmination of Paleozoic metamorphism in the southern Appalachian Blue Ridge. 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.