Acadian orogeny


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Acadian orogeny

[ə′kād·ē·ən ȯr′äj·ə·nē]
(geology)
The period of formation accompanied by igneous intrusion that took place during the Middle and Late Devonian in the Appalachian Mountains.
References in periodicals archive ?
Upper and lower thrust plates were then subjected to upright folding during the Salinic/early Acadian orogeny (Ludman 2013).
Tectonics of the Acadian orogeny in New England and adjacent Canada: Journal of Geology, 91, no.
Termination of the Silurian arc, inversion of the La Poile Basin (O'Brien et al., 1991), pervasive Early Devonian deformation and low- to high-grade metamorphism, and voluminous, largely granitoid magmatism throughout the Gander Zone and immediately adjacent Exploits Subzone, is probably due to the docking of Avalonia (the onset of the Acadian Orogeny).
These country rocks were multiply deformed and metamorphosed to amphibolite-facies conditions during the late Silurian-Early Devonian Acadian orogeny (Gerbi and West 2007).
The Central Maine Basin anal Merrimack Trough are Silurian basins that formed adjacent to or were accreted to the Laurentian margin during the Acadian orogeny. The Early Devonian Carrabassett Formation of the Central Maine Basin and the Kittery Formation of the Merrimack Trough have major and trace element compositions indicative of a passive continental margin provenance, not unlike the older formations of the Central Maine Basin that are thought to have been derived from Laurentian sources.
It represents a portion of Avalonia that was accreted to Laurentia during the Acadian orogeny. For more than thirty years the age of this formation has been regarded as Early Devonian (Lochkovian or Pragian) based on a new and yet undescribed ostracode genus.
This mixed package of rocks was regionally deformed into northeast-trending, open to close, upright folds, and metamorphosed to mainly greenschist facies during the Acadian Orogeny at ~400 [+ or -] 10 Ma (Keppie and Dallmeyer 1987; Kontak et al.
This region was previously thought to have experienced only minor normal fault readjustments after the Middle Devonian Acadian Orogeny. Four SW-striking fault systems with post-Acadian sinistral motion that have been identified along the north shore of Chaleur Bay are described here.
These plutons reflect the resurgence of granite magma at the same crustal location after a very significant time gap and during the waning stages of the Acadian orogeny. Table 1.
The early to mid Devonian "Acadian orogeny" has long been regarded as well developed in the Cobequid Highlands (Donohoe and Wallace 1985).
Extensive plutonism accompanied both phases of the Acadian orogeny. Late Silurian bimodal plutonic rocks (gabbro followed by granite) have now been recognized throughout eastern and coastal Maine (Abbott 1978;Jurinski 1987; Hill and Abbott 1989; Hogan and Sinha 1989; West et al.
The Early to Middle Devonian Acadian orogeny is a tectonic event that has traditionally been attributed to the accretion of Avalonia to the North American craton (Osberg 1978; Dallmeyer et al.