Global geoscience transect 8, Quebec-Maine-Gulf of Maine transect, southeastern Canada, northeastern United States of America

Stewart, David B.; Wright, Bruce E.; Unger, J.D.; Phillips, Jeffrey D.; Hutchinson, Deborah R.

doi:10.3133/ofr91353

Cited by 21 publications

(36 citation statements)

References 37 publications

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“…164-165). These relationships, together with the apparent position of the Chain Lakes above Grenville basement (Stewart et al, 1993), indicate a Laurentian provenance, and a permissive Iapetan rift setting, as suggested by Cousineau (1991).…”

Section: Stratigraphy Of the Bronson Hill Beltmentioning

confidence: 99%

“…Geophysical studies suggest that the massif is a subhorizontal tabular body about 4 km thick, and is either depositionally or structurally directly underlain by Grenville-age basement gneiss (Stewart et al, 1993). The known map distribution of the Chain Lakes indicates that it is a clastic sheet that is caught between the SEdipping hangingwall of the Baie Verte-Brompton suture and the SE-dipping footwall of the Boil Mountain suture (Fig.…”

Section: Stratigraphy Of the Bronson Hill Beltmentioning

confidence: 99%

“…Chain Lakes massif by the Boil Mountain suture (BML). According to the seismic profile of Stewart et al (1993), the massif is a flat-lying tabular body about 4 km thick that is directly underlain by Grenville basement. Although Stewart and others suggested that Chain Lakes rocks were deposited directly on the Grenville, we speculate that the contact is a flat segment of the Baie Verte-Brompton suture (Fig.…”

Section: Summary Of Stratigraphic Correlations Along the Bronson Hillmentioning

confidence: 99%

“…! 1 Southeast edge of Grenville basement: 1, Stewart et al (1993); 2, Hughes and Luetgert (1991); 3, Ando et al (1984). X h Vms deposits having strongly radiogenic lead: X h , Hampshire Hills; X m , Milan; X g , Gardner Mountain.…”

Section: Introductionmentioning

confidence: 99%

“…In order to accomplish this task it was necessary to investigate earlier depictions of accreted terrane structure (e.g. Zen, 1989;Stewart et al, 1993) and to derive a terrane delineation that accommodates the evidence as we see it. Fig.…”

Section: Introductionmentioning

confidence: 99%

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Stratigraphy, geochronology, and accretionary terrane settings of two Bronson Hill arc sequences, northern New England

Moench¹,

Aleinikoff²

2003

Physics and Chemistry of the Earth, Parts A/B/C

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The Ammonoosuc sequence is defined by the Middle Ordovician Ammonoosuc Volcanics near Littleton, NH, the type area, northeast to Milan, NH, and Oquossoc, ME; it also includes black slate of the Partridge Formation (C. bicornis--zone graptolites, $457 Ma). Related metamorphosed intrusives are the tonalitic Joslin Turn pluton (469 AE 2 Ma), the Cambridge Black granitic pluton (468 AE 3 Ma), and gabbro, tonalite (467 AE 4 Ma), and sheeted diabase of the Chickwolnepy intrusions. These intrusives cut lowermost Ammonoosuc (therefore >469 Ma). Probable uppermost Ammonoosuc is dated at 465 AE 6 and 461 AE 8 Ma. Successively below the Ammonoosuc are the Dead River and Hurricane Mountain Formations (flysch and melange), and the Jim Pond Formation (484 AE 5 Ma) and Boil Mountain Complex (both ophiolite), which are structurally underlain by the Neoproterozoic(?) Chain Lakes massif.The Quimby sequence is defined by the Lower Silurian(?) to Upper Ordovician Quimby Formation, composed of bimodal volcanics (443 AE 4 Ma) and sulfidic shale and graywacke that lie conformably to unconformably above the Ammmonoosuc Volcanics and Partridge Formation. Also in the Quimby sequence are several granitic to sparsely gabbroic plutons of the Highlandcroft (441-452 Ma) and Oliverian (435-456 Ma) Plutonic Suites, which intrude the Dead River, Ammonoouc and Partridge, but not the Quimby Formation.Based on faunal, paleolatitude, and isotopic data, the Ammonoosuc sequence and its correlatives and underlying sequences formed off the southern Laurentian margin, but northwest of the principal Iapetan suture, or Red Indian line. The Boil MountainJim Pond-Hurricane Mountain sequence was ramped northwestward over the Chain Lakes massif at $475 Ma, on the basal Boil Mountain surface. This obduction probably occurred slightly before obduction on the Baie Vert-Brompton surface (BBL), farther NW, over the Laurentian margin, and was followed by Dead River flysch sedimentation, which ended with the abrupt onset of Ammonoosuc-sequence arc magmatism at $470 Ma. Ammonoosuc eruptions probably ended at $460 Ma, when Iapetus closed along the Red Indian line.During a following magmatic hiatus of $3-5 m.y., now represented by portions of the Partridge Formation that overlie the Ammonoosuc Volcanics, subduction polarity reversed, and subduction resumed below the northwest-dipping Brunswick subduction complex (BSC) of New Brunswick, Canada. Quimby-sequence magmatism ($456-435 Ma) on the newly accreted Laurentian margin occurred above the BSC, whose footwall is now buried to the southeast by mainly Silurian clastic sediments of the MerrimackFredericton trough, deposited in the ''Fredericton Sea''. In Silurian to Early Devonian time, the NW-dipping BSC footwall was paired with a SE-dipping subduction zone that produced arc magmas of the Coastal Volcanic belt, built on the composite Avalon and adjacent peri-Avalonian terranes. Orogen-normal extension produced by rapid rollback of both subduction zones narrowed the Fredericton Sea, produced the Central Maine and Connecti...

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Section: Stratigraphy Of the Bronson Hill Beltmentioning

confidence: 99%

Section: Stratigraphy Of the Bronson Hill Beltmentioning

confidence: 99%

Section: Summary Of Stratigraphic Correlations Along the Bronson Hillmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Stratigraphy, geochronology, and accretionary terrane settings of two Bronson Hill arc sequences, northern New England

Moench¹,

Aleinikoff²

2003

Physics and Chemistry of the Earth, Parts A/B/C

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Upper crustal investigation of the Gulf of Saint Lawrence region, eastern Canada using ambient noise tomography

et al. 2017

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We studied the 3‐D shear wave velocity (Vs) structure in the Gulf of St. Lawrence (GSL) and adjacent onshore areas to 20 km depth by inverting Rayleigh wave dispersion extracted from the vertical components of continuous ambient seismic noise waveforms. The region is divided into three broad zones based on their Vs characteristics. In the northwest, the Grenville Province (i.e., the exposed edge of predominantly Middle‐Proterozoic Laurentian crust) is dominated by high Vs, except for well‐known anorthosite sites, which are characterized by relatively lower Vs. In contrast, the central segment of the GSL region corresponds to a belt with generally low Vs at upper crustal levels. In the southeastern part of the GSL, prominent low Vs in the uppermost crust are found to coincide with locations of subsidiary basins of the Canadian Maritime Basin, while higher Vs characterize the accreted Appalachian terranes where they are exposed on land. The Grenville Province is wedged out at depth by the Red Indian Line, which is the suture between composite Laurentia and peri‐Godwanan Ganderia in the Canadian Appalachians. The geometry and Vs characteristics of the south‐easternmost peri‐Gondwanan terranes of Avalonia and Meguma suggest that they may be fully or partially structurally overlying a basement with distinct seismic characteristics, which could be a vestige of the West African craton that was underthrust beneath composite Laurentia during the terminal Alleghenian continent‐continent collision. In the middle of the GSL, the 3‐D geometry of the Canadian Maritimes sedimentary basins overlying the Appalachian terranes shows that the depth to the top of basement is in excess of 8 km.

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Characteristic reflection patterns in the Southeast Canadian Cordillera, Northern Appalachians and Swiss Alps

et al. 1993

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Global geoscience transect 8, Quebec-Maine-Gulf of Maine transect, southeastern Canada, northeastern United States of America

Cited by 21 publications

References 37 publications

Stratigraphy, geochronology, and accretionary terrane settings of two Bronson Hill arc sequences, northern New England

Stratigraphy, geochronology, and accretionary terrane settings of two Bronson Hill arc sequences, northern New England

Upper crustal investigation of the Gulf of Saint Lawrence region, eastern Canada using ambient noise tomography

Characteristic reflection patterns in the Southeast Canadian Cordillera, Northern Appalachians and Swiss Alps

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