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Geochemistry And Geochronology Of The Central Metasedimentary Belt Boundary Thrust Zone Thrust Sheets In Southern Ontario, Grenville Province, Kenjo Agustsson
Geochemistry And Geochronology Of The Central Metasedimentary Belt Boundary Thrust Zone Thrust Sheets In Southern Ontario, Grenville Province, Kenjo Agustsson
Natural Resources Management and Environmental Sciences
Studies of pre-Grenvillian (1.4–1.3 Ga) plutons offer insight into the dynamics of arc amalgamation and backarc rifting prior to continental collision in the Ottawan orogeny. The Central Metasedimentary Belt boundary thrust zone (CMBbtz) is a northeast–southwest trending thrust zone consisting of metaplutonic thrust sheets enveloped in gneissic tectonites and calcitic– dolomitic marbles. Tonalitic CMBbtz thrust sheets (Dysart and Redstone) are made up of upper amphibolite-facies, foliation-concordant metatonalites (+ amphibole ± biotite ± accessory zircon and titanite) and amphibolites (± biotite ± clinopyroxene), and are located in the southern Ontario Grenville Province. These thrust sheets are thought to have formed and …
The Evolution Of Grenville Basement In The Eastern Great Smoky Mountains; Constraints From U-Pb Zircon Geochronology, Whole Rock Sm-Nd, And Feldspar Pb Geochemistry, Ryan Joel Quinn
Theses and Dissertations--Earth and Environmental Sciences
Identifying the crustal affinity of Grenville basement rocks in the Dellwood quadrangle, western NC, provides insight into the tectonic evolution of eastern Laurentia during Grenville orogenesis. U-Pb zircon geochronology of orthogneiss, augen gneiss, and mafic xenoliths in orthogneiss reveal magmatic pulses at 1130, 1180, and 1330 Ma and metamorphic episodes at 450 and 1040 Ma. Xenoliths in 1330 Ma orthogneiss are as old as 1382 Ma and represent the oldest component of Blue Ridge basement identified to-date. Feldspar Pb isotope values span a range between juvenile-Laurentian and southern-central Appalachian basement/Amazonia. Most Pb isotope data define an array consistent with crustal …