Mid-Paleozoic orogenesis in the North Atlantic: The Acadian orogeny

Paleozoic evolution of pre-Variscan terranes: From Gondwana to the Variscan collision

“…It is less clear because a large part of the hinterland was lost in the opening of the Atlantic Ocean; it is apparently simpler because the mountain-building processes there appear to be a continuum of deformation (Keppie, 1989;Piqué and Skehan, 1992). Some correlations are proposed between, for example, the Meguma belt and the Ligerian cordillera of central France (Rast and Skehan, 1993), which would somewhat complicate the story. One of the problems to discuss here is the concept of tectonic phases, and, more precisely, the Acadian.…”

Tectonic lithofacies, geophysical, and mineral-resource appraisal maps of the Sherbrooke-Lewiston area, Maine, New Hampshire, and Vermont, United States, and Quebec, Canada

“…The terrane nomenclature shown on figure 1 is ~odified and simplified according to our preferences from many sources (for example, Williams and Hatcher, 1983;Lyons and others, 1982;Zen, 1983Zen, , 1989Stewart and others, 1993;Rankin, ed., 1993;Rast and Skehan, 1993;Ludman and others, 1993;Thompson and others, 1993;Dube and others 1996). Because published geographic terrane nomenclature among the cited references is complex and frequently conflicting, we prefer a simplified numerical nomenclature (T1, T2, and T3, fig.…”

Aquamarine beryl from Zealand Station, Canada: a mineralogical and stable isotope study

“…The Pokiok Batholith consists of five units, from oldest to youngest: Hartfield Tonalite dated at 415 ± 1 Ma (U-Pb titanite), Hawkshaw Granite (411 ± 1 Ma, U-Pb titanite), Skiff Lake Granite (409 ± 2 Ma, U-Pb zircon), Lake George Granodiorite Stock (412 +5/-4 Ma, U-Pb zircon), and Allandale Granite, which was dated at 402 ± 1 Ma by U-Pb monazite (Whalen 1993;Whalen et al 1996). The Pokiok Batholith is the result of the Acadian Orogeny, which is noted for associated syn-to post-tectonic granitoid intrusions from 410 to 380 Ma (Rast and Skehan 1993). This area of New Brunswick is situated in the Central Mobile Belt of the Canadian Appalachian Orogen and is viewed as a result of evolving geological environments involving the opening and closure of the Precambrian-Early Paleozoic Iapetus Ocean (Whalen et al 1996).…”