U‐Pb Geochronologic, Nd Isotopic, and Geochemical Evidence for the Correlation of the Chopawamsic and Milton Terranes, Piedmont Zone, Southern Appalachian Orogen

• Published in: The Journal of geology 2000-07, Vol.108 (4), p.363-380
• Main Authors: Coler, David G., Wortman, Greg L., Samson, Scott D., Hibbard, James P., Stern, Richard
• Format: Article
• Language: English
• Subjects: Continental crust; Crystallization; Geochemistry; Geochronology; Geology; Gneiss; Granite; Mesoproterozoic era; Rhyolite; Rocks; Stone; Volcanic rocks
• ISSN: 0022-1376; 1537-5269
• DOI: 10.1086/314411

We report U‐Pb crystallization ages from four metavolcanic rocks and two granitic gneiss samples as well as whole‐rock chemical analyses and Sm‐Nd isotopic ratios from 25 metaigneous and metasedimentary rocks from the Chopawamsic and Milton terranes, southern Appalachian Orogen. A metarhyolite sample from the Chopawamsic Formation and a metabasalt sample from the Ta River Formation in the Chopawamsic terrane have indistinguishable U‐Pb crystallization ages of \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $471.4\pm 1.3$ \end{document} Ma and \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $470.0+1.3$ \end{document} /−1.5 Ma, respectively. A sample from the Prospect granite that intruded metavolcanic rocks of the Ta River Formation yields a younger U‐Pb date of \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $458.0\pm 1$ \end{document} Ma. Metarhyolite and granitic gneiss samples from the northern part of the Milton terrane yield U‐Pb dates of \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \