Genetic relationship of rift-stage crustal structure, terrane accretion, and foreland tectonics along the southern Appalachian-Ouachita orogen

Thomas, William A.

doi:10.1016/j.jog.2004.02.020

Cited by 46 publications

(37 citation statements)

References 33 publications

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“…Furthermore, Thomas (2004) showed the Talladega belt, restored to at least the present location of the Pine Mountain belt ( Fig. 1), was probably near the location of the eastern Laurentian continental margin.…”

Section: Pumpkinvine Creek Formationmentioning

confidence: 78%

Bimodal volcanism as evidence for Paleozoic extensional accretionary tectonism in the southern Appalachians

Holm-Denoma

Das

2010

Geological Society of America Bulletin

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Detailed mapping, U-Pb ages of igneous and detrital zircons, and isotopic and geochemical characterization of a bimodal volcanic sequence from the Appalachian Blue Ridge province provide constraints for the timing and tectonic setting of volcanism along the Early Paleozoic southeastern Laurentian margin. These units, the Pumpkinvine Creek Formation and related rocks, are interpreted as having been deposited along an extended Laurentian margin in a backarc setting during the mid-Ordovician, and tectonically emplaced as late as the late Paleozoic Alleghanian orogeny. Two felsite layers from the Pumpkinvine Creek Formation, a bimodal metavolcanic sequence, have ages of 466 ± 5 Ma and 461 ± 3 Ma. Geochemical analyses of metabasalts indicate compositions derived from a suprasubduction zone, and more specifi cally a backarc. Furthermore, ε Nd(460 Ma) = (+)3.3-(+)7.7 and 87 Sr/ 86 Sr (initial) = 0.7044-0.7069 indicate a juvenile source. The protoliths of the felsic lithofacies were low-potassium rhyodacite, and have ε Nd(460 Ma) = (−)3.2-(+)4.65 and 87 Sr/ 86 Sr (initial) = 0.709-0.722, suggesting incorporation of an evolved crustal component, which we interpret as Laurentian continental lithosphere. Furthermore, detrital zircons derived from within the Pumpkinvine Creek Formation yielded a majority of ages between 1017 and 1190 Ma, indicating that the source is likely a component of the rifted eastern Laurentian margin. A backarc origin for the Pumpkinvine Creek Formation indicates that the geodynamic setting of the southeastern margin of Laurentia included a retreating subduction zone resulting in extensional accretionary tectonism. These results have implications for the evolution of the southeastern Laurentian margin during a time traditionally linked to collision of an exotic Taconic arc with Laurentia. Additionally, we suggest that there are signifi cant along-orogen disparities that may result from fundamental tectonic boundaries.

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Section: Pumpkinvine Creek Formationmentioning

confidence: 78%

Bimodal volcanism as evidence for Paleozoic extensional accretionary tectonism in the southern Appalachians

Holm-Denoma

Das

2010

Geological Society of America Bulletin

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“…1), where older orogenies created a structural fabric that still persists in the deep lithosphere of modern passive margins (Gao et al, 2008;Ainsworth et al, 2014). Given that the reactivation of inherited structural weaknesses can influence the development and localization of continental rifts (Corti et al, 2007;Chenin et al, 2015), the crustal structure beneath the Gulf coastal plain between Texas and Florida may reflect the geometry of the adjacent Ouachita front, the Paleozoic suture between Laurentia, and accreted terranes of the southeastern United States (Wilson, 1966;Thomas, 2004;Poole et al, 2005;Huerta and Harry, 2012).…”

Section: Geological Setting Inherited Structurementioning

confidence: 99%

Structure and origin of the rifted margin of the northern Gulf of Mexico

et al. 2018

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The wide continental margin of southern Louisiana borders Paleozoic terranes that accreted to Laurentia before Jurassic rifting formed the Gulf of Mexico. It is unclear whether continental rifting here involved widespread or localized crustal extension, or how seafloor spreading in the Gulf of Mexico started. To improve our understanding of this rifting episode, we gathered marine seismic-refraction data along a 396-km-long transect from the continental shelf 50 km off the western Louisiana coast to the central ocean basin as part of the Gulf of Mexico Basin Opening (GUMBO) program. Using travel-time tomography, we imaged the compressional seismic-velocity structure from the shallow sediments to the uppermost mantle. In our geophysical model, the crust tapers in thickness from ~11 km near the Louisiana coast to ~8 km in the deep water of the central Gulf of Mexico. The compressional seismic velocity increases from 5.7 to 5.9 km/s in the shallow basement to 6.8-7.2 km/s above the Moho. The thickness and average wave speed of crust beneath the modern Louisiana coast and continental shelf suggest the presence of uniformly stretched continental crust that was intruded by mantle-derived melts during extension before continental breakup. South of the Sigsbee Escarpment, the crust is thinner with a higher seismic velocity, which is more consistent with thick oceanic crust. A comparison of our seismic-velocity model with coincident seismic-reflection data indicates that the voluminous Louann Salt was likely deposited on rifted continental crust shortly before the onset of seafloor spreading in the Gulf of Mexico.

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“…550-820 Ma are distinguished terranes associated with Gondwana (e.g. Suwannee, Carolina, and Avalon terranes) (Opdyke et al 1987;Hoffman 1989Hoffman , 1999Hanson et al 1994;Mueller et al 1994 (Shaw and Wasserburg 1984;Osberg et al 1989;Tucker and Robinson 1990;Sevigny and Hanson 1993;Sinha et al 1997;Karabinos et al 1998;Aleinikoff et al 2000;Coler et al 2000;Eusden and Anonymous 2000;Miller et al 2000), became an important detrital source, and supplied significant quantities of sediment to the foreland basin and its surrounding area (Nance and Thompson 1996;McLennan et al 2001;Murphy et al 2003;Thomas 2004Thomas , 2011Becker et al 2005;Hietpas et al 2011).…”

Section: The Grenville Province (~900-1350 Ma)mentioning

confidence: 99%

U–Pb detrital zircon evidence of transcontinental sediment dispersal: provenance of Late Mississippian Wedington Sandstone member, NW Arkansas

Xie

Cains

Manger

2016

International Geology Review

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Genetic relationship of rift-stage crustal structure, terrane accretion, and foreland tectonics along the southern Appalachian-Ouachita orogen

Cited by 46 publications

References 33 publications

Bimodal volcanism as evidence for Paleozoic extensional accretionary tectonism in the southern Appalachians

Bimodal volcanism as evidence for Paleozoic extensional accretionary tectonism in the southern Appalachians

Structure and origin of the rifted margin of the northern Gulf of Mexico

U–Pb detrital zircon evidence of transcontinental sediment dispersal: provenance of Late Mississippian Wedington Sandstone member, NW Arkansas

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