ISSN:
1432-0967
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
Notes:
Abstract Eight zircon fractions from the Henderson Gneiss were analyzed from the Brevard mylonites and adjacent Inner Piedmont rocks near Rosman, North Carolina, to determine variations of U/Pb systematics of zircons in a pressure-dominated metamorphism. Substantial uranium gain occurred during zircon recrystallization and size reduction. At Rosman, the Henderson Gneiss zircons probably formed about 600 m.y. ago and now show evidence of being binary mixtures. They experienced mylonitization at about 450 m.y. ago during Taconic deformation and metamorphism in the almandine amphibolite facies. The lower intensity, upper greenschist or greenschist-amphibolite Acadian (360–390 m.y.) metamorphism and mylonitization (recrystallization) had little effect on the zircons but disturbed Rb/Sr systems. The ages of dynamic metamorphism and thrusting (450, 360–390) in the Piedmont and Blue Ridge near and along the Brevard zone at Rosman, North Carolina, agree well with the tectonic interpretations of the Valley and Ridge Taconic (ca. 470-400 m.y.) and Acadian (ca. 375-330 m.y.) clastic wedges. Intermittent thrusting, folding, and uplift rather than continuous secular uplift of the crystalline terrane seems indicated.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00373414
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