Avalon: Insular continent by the latest Precambrian

Landing, Ed

doi:10.1130/0-8137-2304-3.29

Cited by 110 publications

(119 citation statements)

References 79 publications

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“…Although only cursory mapping was carried out in the Beaver Harbour area (Fig. 2), these rocks are also considered to be broadly correlative with the Caledonia belt based on the presence of Middle Cambrian Avalonian fauna in this sequence (Landing 1996).…”

Section: Introductionmentioning

confidence: 99%

“…1). The term Avalon zone (sensu stricto) has been applied to the Traduit par la redaction Caledonia belt as it contains Cambrian-Ordovician strata that are part of the Avalonian cover sequence (Landing 1996). In New Brunswick, Neoproterozoic rocks are exposed in all of these belts except the St. Croix belt; however, rocks of probable Neoproterozoic age underlie equivalent strata in Maine (Tucker et al 2001).…”

Section: Introductionmentioning

confidence: 99%

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Contrasting geology in the Pocologan River and Long Reach areas: implications for the New River belt and correlations in southern New Brunswick and Maine

Johnson¹

2001

atgeol

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The Pocologan River and Long Reach areas are situated in the New River belt, which comprises the westernmost exposures of Neoproterozoic rocks in southern New Brunswick. Previous mapping in the southwestern part of the New River belt indicated that Neoproterozoic and Cambrian rocks in the Pocologan River area are different from coeval strata in the Caledonia belt (Avalon /one sensu stracto) in the Saint John area. Recent mapping in the Long Reach area has shown that there are significant lithological changes across the Robin Hood Lake fault, which bisects the New River belt into northeastern (Long Reach) and southwestern (Pocologan River) segments. Neoproterozoic and Cambrian rocks in the Long Reach area are directly comparable to those in the Caledonia belt, demonstrating that the New River belt is composite. Recent data have also shown that Early Cambrian volcanic activity in the Pocologan River area is broadly contemporaneous with epeirogenic events related to a major sequence boundary in the Avalonian cover sequence. This suggests that the northeastern and southwestern segments of the composite New River belt may have experienced a similar tectonic event, possibly as separate but adjacent continental fragments or as geographically isolated parts of one Gondwanan terrane. The lithological similarity of late Early to (?) Middle Cambrian quartzose sedimentary strata in the Pocologan River area to Middle Cambrian rocks in the St. Croix belt in Maine also supports the suggestion that the St. Croix belt is part of this composite terrane. RÉSUMÉ Les secteurs de la riviére Pocologan et de Long Reach sont situes dans la ceinture de New River, qui englobe les affleurements les plus à I'ouest des roches du Protérozoique supéricur du Sud du Nouveau-Brunswick. Des travaux de cartographic antérieurs dans Ie sud-ouest de la ceinture de New River ont révé;lé que les roches du Protérozoique supeérieur et du Cambrien du secteur de la riviére Pocologan constituaient des exemplaires uniques de stretcs contemporaines de la ceinture de Caledonia (zone d'Avalon au sens strict) dans la région de Saint-Jean. Des travaux de cartographic recents dans le secteur de Long Reach ont révélé des changements lithologiques marqués a travers la faille du lac Robin Hood, qui subdivise la ceinture de New River en deux segments : les segments nord-est (Long Reach) et sud-ouest (riviere Pocologan). Les roches du Protérozoique supérieur et du Cambrien du secteur de Long Reach sont directement comparable? à celles de la ceinture de Caledonia, ce qui démontre que la ceinture de New River constitue unc ceinture composite. Des donées récentes ont également rétvélé que I'activitié volcanique du Cambrien inférieur dans le secteur de la riviére Pocologan a en gros été contemporaine aux phénomenes épirogéniques apparentés à une Iimite de séquence importante dans la séquence de couverture avalonnienne. Cela laisse supposer que les segments nord-est et sud-ouest de la ceinture composite de New River pourraient avoir été soumis a un phénomene tectonique analogue, possiblement en tant que fragments continentaux distincts mais adjacents ou de parties géographiquement isolées d'un terrane du Gondwana. La similarity lithologique des strates seédimentaires quartzeuses de la fin du Cambrien précoce au Cambrien moyen (?) dans le secteur de la riviére Pocologan avec les roches du Cambrien moyen de la ceinture de St. Croix au Maine appuie par ailleurs l’hypothése que la ceinture de St. Croix fail partie de ce terrane composite. Traduit par la rédaction

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Contrasting geology in the Pocologan River and Long Reach areas: implications for the New River belt and correlations in southern New Brunswick and Maine

Johnson¹

2001

atgeol

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“…The age of these structures has been interpreted as either Neoproterozoic (Skehan et al 1981) or post-Cambrian . The latter interpretation is based on the observation that the Cambrian rocks were overthrust by the Neoproterozoic rocks prior to F 2 ; however, Webster et al (1986) and Landing (1996) interpreted the boundary as an overturned unconformity rather than a thrust.…”

Section: Neoproterozoic (Avalonian) Basement Rocksmentioning

confidence: 99%

“…Skehan and Rast (1990) suggested that the Bulgarmarsh terrane may have been thrust northwestward over the Pennsylvanian Narragansett Basin along the Beaverhead shear zone during the Alleghenian orogeny. However, based on its fossil assemblages, Landing (1996) correlated the Conanicut Group with lower to upper Cambrian stratigraphic units characteristic of Avalonia and discounted the existence of a separate Bulgarmarsh terrane.…”

Section: Introductionmentioning

confidence: 99%

Alleghanian deformation of Cambrian metasedimentary rocks on Avalonia in south-central Rhode Island, USA

Carter¹,

Mosher²

2013

atgeol

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Lower greenschist-facies metasedimentary rocks of the Middle Cambrian Conanicut Group occur in and around Beavertail State Park, Rhode Island. Detailed structural mapping (1:1000-scale) and petrology of these rocks indicate an early fold generation (F 1 ) and axial planar metamorphic foliation (S 1 ). F 1 is folded by a more prominent, E-verging, NNE-to NNW-trending, non-coaxial fold generation (F 2 ) and an associated pressure solution-enhanced crenulation cleavage (S 2 ). A third map-scale fold generation is inferred from NNE-trending broad folding of F 2 and S 2 . N-S extension resulted in boudins that deformed S 2 on a scale of 1-10 m, whereas late planar quartz veins indicate NW-SE extension. All structures are cross cut by faults striking N-to NE-and ENEto ESE that show dominantly normal motion with minor sinistral or dextral components. Kink bands associated with faulting trend NNE to ENE with WNW to NNW side up. The vertical Beaverhead shear zone juxtaposes the Cambrian rocks with Pennsylvanian rocks of the Narragansett Basin, and deflects S 2 in a dextral sense, consistent with motion recorded elsewhere.The Cambrian rocks record the same deformation and metamorphism as the adjacent Narragansett Basin rocks. No evidence was found for pre-Alleghanian deformation or for northwest-or north-directed thrusting and accretion of a Meguma-like terrane during the Alleghanian orogeny. If the Beaverhead shear zone was a preexisting terrane boundary within Avalonia, both the Cambrian and Pennsylvanian Narragansett Basin sediments were deposited after terrane accretion. AbStRACt RÉSUMÉDes roches profondes métasédimentaires du faciès des schistes verts, que l' on retrouve dans le groupe Conanicut du Cambrien moyen, sont présentes dans le Beavertail State Park, au Rhode Island, et dans les environs. Une cartographie structurale détaillée (à l' échelle 1:1 000) et la pétrologie de ces roches indiquent la formation précoce d'un pli (F 1 ) et une foliation métamorphique (S 1 ) de plan axial. Le F 1 est causé par la formation d'un pli (F 2 ) non coaxial plus dominant, à vergence est et d' orientation NNE-NNO ainsi que par une schistosité de crénulation (S 2 ) amplifiée en raison d'une dissolution par pression connexe. La formation d'un troisième pli à l' échelle cartographique est provoquée par un vaste plissement du F 2 et de la S 2 d' orientation NNE. Une extension N-S a produit des boudins qui déforment la S 2 sur l' échelle de 1 à 10 m, tandis que des veines de quartz planes formées ultérieurement indiquent une extension NO-SE. Toutes les structures sont traversées par des failles orientées N-NE et ENE-ESE montrant un mouvement normal dominant accompagné de composantes senestres et dextres peu importantes. Les bandes froissées associées à ces failles sont orientées NNE-ENE et présentent une tangente verticale ONO-NNO. Dans la zone de cisaillement verticale de Beaverhead, les roches du Cambrien sont juxtaposées aux roches de la Pennsylvanie du bassin Narragansett, et la S 2 dévie en un mouvement dextre, ce qui concorde...

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“…The Ediacaran strata of eastern Newfoundland and the United Kingdom contain some of the Ediacaran Period (Landing, 1996). Avalonian fossil assemblages record a variety of soft-44 bodied organisms, widely termed the Ediacaran biota, which have proven difficult to classify 45 within modern biological groups (e.g., Laflamme et al, 2013).…”

mentioning

confidence: 99%

Confirming the Metazoan Character of a 565 Ma Trace-Fossil Assemblage From Mistaken Point, Newfoundland

Liu¹,

McIlroy²,

Matthews³

et al. 2014

PALAIOS

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Avalon: Insular continent by the latest Precambrian

Cited by 110 publications

References 79 publications

Contrasting geology in the Pocologan River and Long Reach areas: implications for the New River belt and correlations in southern New Brunswick and Maine

Contrasting geology in the Pocologan River and Long Reach areas: implications for the New River belt and correlations in southern New Brunswick and Maine

Alleghanian deformation of Cambrian metasedimentary rocks on Avalonia in south-central Rhode Island, USA

Confirming the Metazoan Character of a 565 Ma Trace-Fossil Assemblage From Mistaken Point, Newfoundland

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