Petrochemical and geochronological studies of plutonic rocks in the southern Appalachians: III. Leucocratic adamellites of the Charlotte belt near Salisbury, North Carolina

The Salisbury, Yadkin, Southmont, Gold Hill, and Kannapolis plutons and related smaller bodies in the Charlotte belt of central North Carolina are leucocratic albite adamellite. The Rb-Sr whole-rock ages for these plutons are 413 to 386 m.y., and the Salisbury-group granites generally have low initial Sr⁸⁷/Sr⁸⁶ ratios near 0.703. A mica date of 368 m.y. is an upper bracket for metamorphism. The Gold Hill fault truncates the Gold Hill pluton; major movement probably occurred between about 400 and 368 m.y. ago. Gold mineralization apparently is younger than major deformation. The gold deposits are strongly localized in shear zones, although some gold-bearing veins cut the Gold Hill and Salisbury plutons. Acadian deformation in this part of the southern Appalachians is mainly restricted to shear zones trending about 25° east of north and was accompanied or followed by lower–greenschist-facies metamorphism that overprinted an earlier greenschist- to amphibolite-facies metamorphism.