Geochemistry, Nd, Pb and Sr Isotope Systematics, and U-Pb zircon ages of the Neoarchean Bad Vermilion Lake Greenstone Belt and Spatially Associated Granitic rocks, Western Superior Province, Canada | Posted on:2016-10-21 | Degree:M.Sc | Type:Thesis | University:University of Windsor (Canada) | Candidate:Wu, Tuoyu | Full Text:PDF | GTID:2470390017481053 | Subject:Geology | Abstract/Summary: | | The Neoarchean (ca. 2720 Ma) Bad Vermilion Lake (BVL) greenstone belt is composed of metamorphosed bimodal tholeiitic to calc-alkaline basalts to rhyolites, volcaniclastic rocks, gabbros, and subordinate sedimentary rocks. All these rocks are intruded by granitic rocks.;The HFSE systematics of the volcanic and volcaniclastic rocks and gabbros are consistent with subduction zone geochemical signatures. The BVL greenstone belt is geochemically similar to Neoarchean subduction-related ophiolites. Two rhyolite samples from the belt have been dated as 2724+/-23 Ma and 2722+/-11 Ma, representing approximate age of the arc volcanism. The ca. 2664 Ma Ottertail Lake granite marks the end of tectonic accretion in the study area.;Both the volcanic rocks and gabbros show large ranges of Nd, Pb and Sr isotopic compositions, reflecting post-magmatic alteration. Pb-Pb regression ages of gabbros (2725+/-83 Ma) agree with the U-Pb ages of the rhyolites, suggesting that the U-Pb system was the most robust isotopic systems. | Keywords/Search Tags: | Greenstone belt, Rocks, U-pb, Ages, Neoarchean, Lake | | Related items |
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