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Neoacadian Phase

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Journal Article
Journal: Geology
Published: 22 April 2021
Geology (2021) 49 (8): 946–951.
...Ian W. Hillenbrand; Michael L. Williams Abstract The Acadian and Neoacadian orogenies are widely recognized, yet poorly understood, tectono-thermal events in the New England Appalachian Mountains (USA). We quantified two phases of Paleozoic crustal thickening using geochemical proxies. Acadian (425...
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Series: Geological Society, London, Special Publications
Published: 01 January 2009
DOI: 10.1144/SP327.13
EISBN: 9781862395756
... granitoid-dominated pulses are explained as products of slab-breakoff rather than contemporaneous slab subduction. The four phases of orogenesis associated with accretion of these microcontinents are known as the Taconic, Salinic, Acadian and Neoacadian orogenies, respectively. The Ordovician Taconic...
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Series: GSA Memoirs
Published: 11 September 2017
DOI: 10.1130/2017.1213(10)
EISBN: 9780813782133
... less than 0.1. Results of 206 Pb/ 238 U ages, ±2% discordant, range from 481 to 305 Ma. Clustering within these data reveals that the Blue Ridge and Inner Piedmont terranes were affected by three tectonothermal events: (1) 462–448 Ma (Taconic); (2) 395–340 Ma (Acadian and Neoacadian); and (3) 335–322...
Series: GSA Field Guide
Published: 01 January 2012
DOI: 10.1130/2012.0029(11)
EISBN: 9780813756295
... southward in time. Once thought to be the fourth tectophase of the Acadian orogeny, this event is now called the Neoacadian orogeny. Active deformational loading during the event initially produced the Sunbury black-shale basin, whereas subsequent relaxational phases produced the Borden-Grainger-Price...
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Journal Article
Journal: Geology
Published: 01 October 2016
Geology (2016) 44 (10): 871–874.
... the full duration of Appalachian orogenesis, particularly the Neoacadian and Alleghanian tectonic phases ( Fig. 2 ). The insensitivity of the U-Pb detrital zircon system to magma-poor Neoacadian and Alleghanian orogenesis in the southern Appalachians, a region central to the Paleozoic evolution...
Journal Article
Published: 01 October 2015
American Mineralogist (2015) 100 (10): 2254–2271.
... crop out in the southern end of the Central Maine Terrane and thus are a part of the Acadian/Neoacadian Orogen. The typical mineral assemblage is garnet + sillimanite + K-feldspar + plagioclase + quartz + cordierite + biotite ± spinel. The sillimanite is commonly pseudomorphous after kyanite...
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Series: GSA Memoirs
Published: 01 January 2004
DOI: 10.1130/0-8137-1197-5.525
... in the core near the southwest end. The coarse augen gneiss phase constitutes a larger proportion of the Toxaway Gneiss toward the northeast. Field evidence indicates that the augen phase intruded the banded Toxaway lithology; U/Pb isotopic ages of these lithologies, however, are statistically...
Journal Article
Published: 01 November 2018
American Mineralogist (2018) 103 (11): 1851–1868.
...Duncan S. Keller; Jay J. Ague Abstract We quantify the metamorphic pressure-temperature ( P-T ) conditions for a newly discovered silica-undersaturated high-pressure granulite (HPG) from the Central Maine Terrane (CMT) in northeastern Connecticut, U.S.A. The rocks lie within the Acadian-Neoacadian...
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Journal Article
Journal: Geosphere
Published: 02 November 2021
Geosphere (2021) 17 (6): 1840–1860.
... and Ridge. Both the Cambrian Chilhowee Group and Pennsylvanian Pottsville Formation exhibit (U-Th)/He dates ranging from 507 to 263 Ma with a Mississippian subset (353–329 Ma, n = 4), which indicates rapid cooling and inferred exhumation during Late Devonian–Early Mississippian Neoacadian tectonism. We...
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Journal Article
Journal: Lithosphere
Publisher: GSW
Published: 14 August 2019
Lithosphere (2019) 11 (5): 722–749.
... of more than 40 m.y. during and following Neoacadian deformation in the eastern Blue Ridge of Alabama. Garnet Sm-Nd geochronology, pressure-temperature ( P - T ) phase diagram sections (pseudosections), and thermobarometry were applied to the host metasedimentary rocks that were metamorphosed during...
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Journal Article
Journal: Lithosphere
Publisher: GSW
Published: 01 December 2009
Lithosphere (2009) 1 (6): 337–342.
... at ca. 390 Ma and was associated with widespread migmatization. A third metamorphic event (M3) occurred during the ca. 378–371 Ma time interval and was possibly associated with the Neoacadian orogeny. Intermittent monazite growth during the 360–305 Ma interval suggests that the main phase...
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Journal Article
Published: 21 September 2015
Canadian Journal of Earth Sciences (2015) 52 (10): 921–937.
... to the contact, the Alleghanian cleavage (S 2 ) is parallel to the contact in both units, with S 0 in the White Rock Formation metavolcanic rocks and Halifax slate parallel to and discordant to the contact. The geometry of deformed Neoacadian minor folds, quartz fringes on sulphide grains, and micro...
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Journal Article
Journal: GSA Bulletin
Published: 16 May 2017
GSA Bulletin (2017) 129 (9-10): 1195–1208.
...–Mississippian and refer to this tectonic phase as the Neoacadian ( Hatcher, 1987 ; Hatcher et al., 2007 ). Others consider the Acadian orogeny to be largely absent in this region aside from local magmatism and metamorphism ( Hibbard, 2000 ). In either case, metamorphism documented for this Acadian-Neoacadian...
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Journal Article
Published: 01 July 2016
The Canadian Mineralogist (2016) 54 (4): 945–969.
... to Mississippian Neoacadian orogeny and the Pennsylvanian to Permian Alleghanian orogeny. Thus the New England LCT pegmatites were emplaced during the latter stages of the assembly of Pangea. 40 Ar/ 39 Ar muscovite ages from 11 LCT and one NYF pegmatites range from ca . 339 to ca . 243 Ma and are interpreted...
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Journal Article
Published: 11 November 2014
Geological Magazine (2015) 152 (5): 767–787.
... to directly date mineral reactions and hence metamorphic equilibrium assemblages, but also ductile deformation in white mica-bearing rocks. Deformation-induced recrystallization of white mica and associated phases will generally lead to complete Sr-isotopic re-equilibration...
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Journal Article
Published: 19 June 2012
Canadian Journal of Earth Sciences (2012) 49 (7): 781–795.
... facies (locally to lower amphibolite facies) and deformed into north- and northeast-trending folds with associated axial planar cleavage during the Middle Devonian ( Hicks et al. 1999 ), an event referred to here as the Neoacadian orogeny following van Staal (2007) and White et al. (2007) . They were...
FIGURES
Journal Article
Journal: Geology
Published: 15 October 2019
Geology (2019) 47 (12): 1189–1192.
... 08 2019 12 09 2019 12 09 2019 © 2019 Geological Society of America 2019 Garnet’s resilience as a moderately to highly stable phase during weathering, transport, and deposition makes it a common component of clastic sediments and sedimentary rocks with metamorphic source...
FIGURES
Journal Article
Journal: Geosphere
Published: 01 June 2013
Geosphere (2013) 9 (3): 647–666.
... in the hinterland. The 40 Ar/ 39 Ar hornblende and muscovite dates record late Mississippian cooling and exhumation from the Late Devonian (Neoacadian orogeny, 380–340 Ma) peak. Retrograde mylonites of the Goodwater-Enitachopco fault are of two types. Earlier formed, type 1, upper greenschist to lower amphibolite...
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Journal Article
Published: 06 April 2021
Canadian Journal of Earth Sciences (2021) 58 (10): 1103–1115.
... to the Gondwana continent centred on the South Pole, Laurussia was located at equatorial latitudes stretching from the equator to 60 °S during the Early Devonian ( Torsvik et al. 2012 ). The Neoacadian Orogeny is interpreted to record the Early Devonian arrival and deformation of the Meguma terrane ( Hicks et al...
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Series: GSA Memoirs
Published: 01 January 2007
DOI: 10.1130/2007.1200(27)
... clastic wedge ( Tull, 2002 ). The final tectonic phase persisted from Mississippian to early Pennsylvanian time, during which it migrated southward from its initiation at the Virginia promontory ( Ettensohn, 1985 , 2004 ). Tectophases two through four temporally overlap Neoacadian deformation...
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