Right lateral oblique slip movements followed by post-Ottawan (1050–1020 Ma) orogenic collapse along the Carthage-Colton shear zone: Data from the Dana Hill metagabbro body, Adirondack Mountains, New York
Published:January 01, 2004
Eric L. Johnson, Eric T. Goergen, Benjamin L. Fruchey, 2004. "Right lateral oblique slip movements followed by post-Ottawan (1050–1020 Ma) orogenic collapse along the Carthage-Colton shear zone: Data from the Dana Hill metagabbro body, Adirondack Mountains, New York", 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 Dana Hill metagabbro body is a small (5 × 1.5 km) gabbroic intrusion located along the boundary between the Adirondack Highlands (Central Granulite Terrane) and the Adirondack Lowlands (Central Metasedimentary Belt). The Dana Hill metagabbro body crops out in the belt of highly strained rock known as the Carthage-Colton shear zone. Six generations of deformational and veining events cut the Dana Hill metagabbro body and are used to delineate a deformation or mineralization history for the body. Geothermometric data for multiple early-formed shear zones record temperatures of 770–711 °C ± 50 °C, with early-formed shear zones recording predominately right-lateral oblique-to-strike slip and later events recording oblique-to-dip slip motions. Deformation in the Dana Hill metagabbro body ended with folding and brecciation at greenschist-facies conditions. Early in its deformational history, the Dana Hill metagabbro body records a major episode of high-temperature (>700 °C) fluid infiltration (CO2-rich) that was marked by scapolite replacement of plagioclase along swarms of parallel hornblende veins. This event was also recorded locally in the Central Metasedimentary Belt terrane, indicating that the two terranes were at or close to the same structural level during this event. Published geochronologic data (Streepey et al., 2001) show that the Dana Hill metagabbro body cooled to 650 °C by 1020 Ma, thereby constraining fluid infiltration and Central Metasedimentary Belt–Central Granulite Terrane juxtaposition to have occurred at or prior to this time. Structural, petrologic, and published geochronologic data support early (Ottawan) oblique-to-strike slip movements along the Carthage-Colton shear zone during the Ottawan orogeny (1090–1030 Ma), followed by a period of orogenic collapse that brought the two terranes to a common structural level prior to 1020 Ma.