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New U-Pb zircon ages from volcanic, plutonic, and sedimentary units in the Avalonian Caledonia terrane of southern New Brunswick provide better timing constraints in this geologically complex area. Previous ca. 620 Ma ages from the Broad River Group are now corroborated by additional dates from felsic tuff in the Gordon Falls Formation and rhyolite in the former Fairfield (now East Branch Black River) Formation of 620 [+ or -] 5 Ma and 622 [+ or -] 1.9 Ma, respectively. Combined with ages ranging from ca. 625 Ma to 615 Ma from cross-cutting plutons, the data suggest that the minimum age of the Broad River Group is about 615 Ma. A quartz-feldspar porphyry dyke in mafic volcanic rocks of the previously undated Long Beach Formation yielded an igneous crystallization age of 685 [+ or -] 10 Ma, the oldest unit yet dated in the Caledonia terrane but similar in age to porphyry in the Stirling belt in the Avalonian Mira terrane of Nova Scotia. The age of the Coldbrook Group was constrained previously by U-Pb (zircon) ages of volcanic rocks between 560 and 550 Ma as well as by similar ages from comagmatic plutons. Five additional samples from both volcanic and plutonic units lie in the same range of 560-550 Ma, including errors, demonstrating that the Coldbrook Group and related plutons formed in less than 10 million years. Such a large volume of mainly felsic magma erupted and emplaced in a short time span suggests a 'supereruption/supervolcano' environment such as the late Cenozoic southwestern USA but not yet recognized at ca. 560-550 Ma elsewhere in Avalonia. Two units yielded Paleozoic ages: felsite of the Bloomsbury Mountain Formation with a zircon population at 427 [+ or -] 9 Ma, indicating a Silurian maximum emplacement age, and dacite of the Grassy Lake Formation with several zircon grains at 382.8 [+ or -] 8.3 Ma, indicating a maximum age of middle Devonian, the first rocks of this age to be identified in the Caledonia terrane. De nouveaux ages U - Pb sur zircon provenant d'unites volcaniques, plutoniques et sedimentaires dans le terrane avalonien Caledonie du sud du Nouveau-Brunswick fournissent de meilleures contraintes temporelles dans cette region geologiquement complexe. Les ages d'environ 620 Ma precedemment obtenus du Groupe de Broad River sont maintenant appuyes par des dates supplementaires provenant du tuf felsique dans la Formation de Gordon Falls et de la rhyolite dans l'ancienne Formation de Fairfield (maintenant East Branch Black River) de 620 [+ or -] 5 Ma et 622 [+ or -] 1,9 Ma, respectivement. Combine avec des ages allant de 625 Ma a 615 Ma a partir de plutons encaisses, les donnees suggerent que l'age minimum du Broad River Group est d'environ 615 Ma. Un dyke de porphyre de quartz-feldspath dans des roches volcaniques mafiques de la Formation de Long Beach non datee a donne un age de cristallisation ignee de 685 [+ or -] 10 Ma, la plus ancienne unite encore datee dans le terrane de Caledonie mais similaire en age au porphyre dans la ceinture de Stirling dans le terrane avalonien Mira de la Nouvelle-Ecosse. L'age du Groupe de Coldbrook etait auparavant limite par les ages U - Pb (zircon) des roches volcaniques entre 560 et 550 Ma, ainsi que par les ages similaires des plutons co-magmatiques. Cinq echantillons supplementaires provenant des unites volcaniques et plutoniques se situent dans la meme periode de 560 a 550 Ma, y compris les erreurs, demontrant que le Groupe de Coldbrook et les plutons associes se sont formes en moins de 10 millions d'annees. Un volume aussi important de magma principalement felsique ayant entre en eruption et mis en place dans un court laps de temps suggere un environnement de 'super-eruption / supervolcan' tel que le sud-ouest du Cenozoique superieur aux etats-Unis, mais pas encore reconnu entre 560-550 Ma ailleurs dans la zone d'Avalonia. Deux unites ont donne des ages paleozoiques: la felsite de la Formation de Bloomsbury Mountain avec une population de zircon a 427 [+ or -] 9 Ma, indiquant un age de mise en place maximal du Silurien, et la dacite de la Formation de Grassy Lake avec plusieurs grains de zircon a 382,8 [+ or -] 8,3 Ma, indiquant un age maximal du Devonien moyen, premieres roches de cet age identifiees dans le terrane de Caledonie. [Traduit par la redaction], INTRODUCTION The Caledonia terrane is a large area of mainly Neoproterozoic rocks that forms the Avalonian part of southern New Brunswick, extending from the Saint John area to the northeast [...]

The Belleisle Fault (Lubec Fault in southeast Maine) is one of several large strike-slip faults in the Appalachians of Maritime Canada. For much of its length, the Belleisle Fault is [...]

Red-bed strata exposed at Lepreau Falls, southern New Brunswick, were originally interpreted as belonging to the Triassic Lepreau Formation. Poorly preserved tetrapod trackways within the strata were previously assigned to two ichnospecies; one to a new Triassic ichnospecies, Isocampe lepreauense Sarjeant and Stringer, and the other to Rhynchosauroides cf. R. franconicus (Heller). Both were attributed to reptiles. Subsequent mapping of the rocks and reassignment of the exposed strata at Lepreau Falls to the Mississippian Mabou Group prompted our re-examination of the trackway fossils. Isocampe lepreauense was described from a specimen block preserving three trackways and the original description was based on erroneous interpretation of extramorphological digit drags. Rhynchosauroides cf. R. franconicus was a tentative assignment in a letter accompanying a cast in the New Brunswick Museum, but was never formally published. We redescribe and re-interpret all the trackways as gait variations produced by temnospondyls, and most closely resemble the Carboniferous ichnotaxon Matthewichnus. Au depart, on croyait que les strates de couches rouges exposees aux chutes Lepreau, dans le sud du Nouveau-Brunswick, appartenaient a la formation de Lepreau, qui etait datee du Trias. Des empreintes de tetrapode mal conservees presentes dans les strates avaient d'abord ete attribuees a deux ichnoespeces, soit a une nouvelle ichnoespece du Trias, Isocampe lepreauense (Sarjeant et Stringer), et a Rhynchosauroides cf. R. franconicus (Heller). Les deux etaient attribuees a des reptiles. Une cartographie ulterieure des roches et la reattribution au groupe Mabou du Mississippien des strates exposees des chutes Lepreau nous ont amenes a reexaminer les fossiles. La description d'Isocampe lepreauense a ete effectuee au moyen d'un bloc de specimen contenant trois empreintes, tandis que la description d'origine se fondait sur une interpretation erronee dempreintes extramorphologiques. Rhynchosauroides cf. R. franconicus a ete attribue de facon provisoire dans une lettre accompagnant une contre-empreinte conservee au Musee du Nouveau-Brunswick, qui na toutefois jamais ete officiellement publiee. Nous redecrivons et reinterpretons toutes les empreintes comme des variations de la demarche de temnospondyles, qui ressemblent davantage a l'ichnotaxon du Carbonifere Matthewichnus. [Traduit par la redaction], INTRODUCTION Tetrapod trackways discovered at Lepreau Falls Provincial Park, New Brunswick (Fig. 1), in rocks thought to be Triassic in age, formed the basis for a new ichnospecies, Isocampe lepreauense [...]

The Partridge Island block is a newly identified tectonic element in the Saint John area of southern New Brunswick, located south of and in faulted contact with Proterozoic and Cambrian rocks of the Ganderian Brookville and Avalonian Caledonia terranes. It includes the Lorneville Group and Tiner Point complex. The Lorneville Group consists of interbedded volcanic and sedimentary rocks, subdivided into the Taylors Island Formation west of Saint John Harbour and West Beach Formation east of Saint John Harbour. A sample from thin rhyolite layers interbedded with basaltic flows of the Taylors Island Formation at Sheldon Point yielded a Late Devonian - Early Carboniferous U-Pb (zircon) age of 358.9 +6/-5 Ma. Petrological similarities indicate that all of the basaltic rocks of the Taylors Island and West Beach formations are of similar age and formed in a continental within-plate tectonic setting. West of Saint John Harbour, basaltic and sedimentary rocks of the Taylors Island Formation are increasingly deformed and mylonitic to the south, and in part tectonically interlayered with mylonitic granitoid rocks and minor metasedimentary rocks of the Tiner Point complex. Based on magnetic signatures, the deformed rocks of the Tiner Point complex can be traced through Partridge Island to the eastern side of Saint John Harbour, where together with the West Beach Formation, they occupy a thrust sheet above a redbed sequence of the mid-Carboniferous Balls Lake Formation. The Tiner Point complex includes leucotonalite and aegirine-bearing alkali-feldspar granite with A-type chemical affinity and Early Carboniferous U-Pb (zircon) ages of 353.6 ± 5.7 and 346.4 [+ or -] 0.7 Ma, respectively. Based on similarities in age, petrological characteristics, alteration, iron oxide--copper-gold (IOCG)-type mineralization, and deformation style, the Partridge Island block is correlated with Late Devonian--Early Carboniferous volcanic- sedimentaryplutonic rocks of the Cobequid Highlands in northern mainland Nova Scotia. Deformation was likely a result of dextral transpression along the Cobequid-Chedabucto fault zone during juxtaposition of the Meguma terrane. Le bloc de Partridge Island est un element tectonique nouvellement identifie dans la region de Saint John du sud du Nouveau-Brunswick; il est situe au sud et dans un contact de faille avec des roches datant du Proterozoique et du Cambrien des terranes de Brookville (Ganderien) et de Caldonia (Avalonien). Le bloc comprend le Groupe de Lorneville et le complexe de Tiner Point. Le Groupe de Lorneville est forme de roches volcaniques et sedimentaires interlitees, subdivisees entre la Formation de Taylors Island a l'ouest du port de Saint John et la Formation de West Beach a l'est. Un echantillon de minces couches de rhyolite interlitees avec des ecoulements basaltiques de la Formation de Taylors Island a la pointe Sheldon a donne un age Devonien tardif - Carbonifere precoce de 358,9 +6/-5 Ma, determine par U-Pb sur zircon. Des similitudes petrologiques indiquent que toutes les roches basaltiques des formations de Taylors Island et de West Beach ont un age similaire et qu'elles ont ete formees dans un environnement continental a l'interieur d'une plaque tectonique. A l'ouest du port de Saint John, des roches basaltiques et sedimentaires de la Formation de Taylors Island sont de plus en plus deformees et mylonitiques vers le sud; elles sont aussi en partie interlitees tectoniquement avec des roches granitoides mylonitiques et des roches metasedimentaires accessoires du complexe de Tiner Point. En se basant sur les signatures magnetiques, les roches deformees du complexe de Tiner Point peuvent etre retracees a travers l'lle Partridge, jusqu'au cote est du port de Saint John ou, avec la Formation de West Beach, elles forment une nappe de charriage au-dessus d'une sequence de lits rouges de la Formation de Balls Lake (Carbonifere moyen). Le complexe de Tiner Point comprend des granites alcalins feldspathiques avec une tonalite leucocrate et de l'aegyrine qui ont une affinite chimique de type A; ils datent du Carbonifere precoce et ont des ages respectifs de 353,6 ± 5,7 et 346,4 ± 0,7 Ma determines par datation U-Pb sur zircons. En se basant sur les similitudes d'age, les caracteristiques petrologiques, l'alteration, la mineralisation de type IOCG (oxyde de fer, cuivre, or) et le style de deformation, le bloc de Partridge Island est correle avec les roches volcaniques sedimentaires plutoniques (Devonien tardif - Carbonifere precoce) des hautes terres de Cobequid dans le nord de la partie continentale de la Nouvelle-Ecosse. La deformation proviendrait d'une transpression dextre le long de la zone de failles Cobequid-Chedabucto durant la juxtaposition du terrane de Meguma. [Traduit par la Redaction], Introduction Southern New Brunswick consists of a collage of inferred peri-Gondwanan terranes and terrane fragments (Fig. 1), some of which may have been part of the microcontinent of Ganderia and [...]

Three Appalachian tectonostratigraphic terranes converge in the Beaver Harbour area of southern New Brunswick, overlain by two upper Paleozoic sedimentary sequences. The Ediacaran to Cambrian New River and Brookville terranes [...]

ABSTRACT The Weldon Formation of the Lower Carboniferous (Tournaisian) Sussex Group of southeastern New Brunswick consists of red mudstone intervals interbedded with red siltstone and fine-grained sandstone. Some of the [...]

ABSTRACT A major ductile high-strain zone up to 5 km in width can be traced for at least 70 km diagonally across the Avalonian Caledonia terrane of southern New Brunswick. [...]

ABSTRACT Excavations along the 23 km stretch of the Longs Creek to Fredericton section of the new Trans-Canada Highway created new exposures affording a transect through part of the Fredericton [...]

Tectonostratigraphic terrane analysis of the western and central Baltic Shield defines a framework for continental growth through the period 2.50-1.75 Ga. Eight discrete terranes can be defined in this part of the Svecokarelian orogen: the older cratonic Kuhmo and Iisalmi terranes, the hybrid Lapland and Savo province allochthonous terranes, the juvenile island-arc-like Skellefte-Savonlinna and south Finland-central Sweden terranes, the back-arc or arc-like Outokumpu nappe, and the ophiolitic (oceanic?) Jormua nappe. Stitching events can also be recognized. These include the ca. 1.88-1.87 Ga Svionian magmatic arc, the ca. 2.44 Ga Koillismaa intrusions, the Kalevian flysch basin, and the Bothnian basin. Constraining the age of these stitching events permits the construction of an accretion history in which the 'Svecokarelian orogeny' can be resolved as a number of accretion events, deformation episodes related to accretion or magmato-tectonic episodes. These events, defined here, include the pre-2.44 Ga Pohjolan accretion of the component parts of the Lapland hybrid terrane, the ca. 1.95 Ga Kyllikian accretion of the Karelian collage, the ca. 1.90 Ga Karelian orogeny marked by the development of the Savo thrust belt in response to the accretion of the Skellefte-Savonlinna terrane to the Karelian collage, and the ca. 1.88-1.87 Ga Svionian magmatic arc. The whole Svecokarelian collage had assembled by ca. 1.85 Ga, an amalgamation succeeded and stitched by a diverse collection of igneous and thermal events through the period 1.85-1.75 Ga.