Deformation of the Diana syenite and Carthage-Colton mylonite zone: Implications for timing of Adirondack Lowlands deformation
Published:January 01, 2004
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Graham B. Baird, William D. MacDonald, 2004. "Deformation of the Diana syenite and Carthage-Colton mylonite zone: Implications for timing of Adirondack Lowlands deformation", Proterozoic Tectonic Evolution of the Grenville Orogen in North America, Richard P. Tollo, James McLelland, Louise Corriveau, Mervin J. Bartholomew
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The Carthage-Colton mylonite zone is a major geothermochronological discontinuity across the northwest Adirondack Mountains of New York, a southern extension of the Grenville Province. A large syenitic gneiss body, the Diana syenite, occurs along most of the southern Carthage-Colton mylonite zone. The present study examined petrofabrics and magnetofabrics of oriented cores and accurately oriented thin- sections to investigate the sources of anisotropy of magnetic susceptibility (AMS) within a central portion of the Diana syenite. Three petrographic foliations, a petrographic lineation, and a magnetic intersection lineation were clearly distinguished. Two of the foliations appear to represent axial planar foliations of the second- and third-phases of regional folding as defined by Wiener (1983). The youngest foliation and the magnetic intersection lineation have not been previously described. This research suggests that folding identified in the Adirondack Lowlands can be traced to at least the southwest margin of the Diana syenite with no obvious discontinuity. Significant implications of this research suggest that: (1) the Adirondack Lowlands deformation likely includes some folding events associated with Ottawan orogen compression, and (2) the kinematics and style of deformation within the Carthage-Colton mylonite zone remain cryptic and cannot conclusively be connected to the fabrics explored in this research.