Lower Silurian-Lower Devonian Volcanic Rocks of New England Coast and Southern New Brunswick

1969 ◽  
Author(s):  
Olcott Gates
Keyword(s):  
New Brunswick ◽  
New England ◽  
Lower Devonian ◽  
Volcanic Rocks ◽  
Lower Silurian

scholarly journals Stratigraphy and volcanology of a portion of the Lower Devonian volcanic rocks of southwestern New Brunswick

1988 ◽  
Author(s):  
N A van Wagoner ◽  
V K Fay
Keyword(s):  
New Brunswick ◽  
Lower Devonian ◽  
Volcanic Rocks

Geochemistry of Sainte-Marguerite volcanic rocks: implications for the evolution of Silurian–Devonian volcanism in the Gaspé Peninsula

2008 ◽  
Vol 45 (1) ◽  
pp. 15-29 ◽  
Author(s):  
Alan D’hulst ◽  
Georges Beaudoin ◽  
Michel Malo ◽  
Marc Constantin ◽  
Pierre Pilote
Keyword(s):  
Lower Devonian ◽  
Volcanic Rocks ◽  
Magma Source ◽  
Volcanic Arc ◽  
Lower Silurian ◽  
Trace Element Signature ◽  
Arc Setting ◽  
Back Arc ◽  
Gaspe Peninsula ◽  
Gaspé Peninsula

The Lower Devonian Sainte-Marguerite volcanic rocks are part of a Silurian–Devonian volcanic sequence deposited between the Taconian and Acadian orogenies in the Gaspé Peninsula, Quebec, Canada. The Sainte-Marguerite unit includes basaltic and dacitic lava flows with calc-alkaline and volcanic-arc affinities. Such affinities are also recorded by the trace-element signature in Lower Silurian and most Lower Devonian volcanic units of the Gaspé Peninsula. However, most of the other Silurian–Devonian volcanic rocks occurring in the Gaspé Peninsula have been previously interpreted to have erupted in an intracontinental setting. A back-arc setting for the Gaspé Peninsula between the Taconian and Acadian orogenies could account for these subduction volcanic-arc signatures, though a metasomatized lithospheric mantle magma source, unrelated to subduction, cannot be excluded. Lower Silurian and Lower Devonian volcanic rocks in the central part of the Gaspé Peninsula show an arc affinity, whereas Upper Silurian and Lower to Middle Devonian volcanic rocks, located in the south and north of the Gaspé Peninsula, respectively, show a within-plate affinity. The Lower Devonian Archibald Settlement and Boutet volcanic rocks of the southern and northern Gaspé Peninsula, respectively, show a trend toward a within-plate affinity. This suggests that within-plate volcanism migrated from south to north through time in an evolving back-arc environment and that the subduction signature of Lower Silurian and Lower Devonian rocks results from a source that melted only under the central part of the Gaspé Peninsula.

Superposed Neoproterozoic and Silurian magmatic arcs in central Cape Breton Island, Canada: geochemical and geochronological constraints

2000 ◽  
Vol 137 (2) ◽  
pp. 137-153 ◽  
Author(s):  
J. D. KEPPIE ◽  
J. DOSTAL ◽  
R. D. DALLMEYER ◽  
R. DOIG
Keyword(s):  
New Brunswick ◽  
New England ◽  
Volcanic Rocks ◽  
Geochemical Data ◽  
Zircon Age ◽  
Cape Breton Island ◽  
Northern Margin ◽  
Element Abundances ◽  
Southern New England ◽  
Cape Breton

Isotopic and geochemical data indicate that intrusions in the eastern Creignish Hills of central Cape Breton Island, Canada represent the roots of arcs active at ∼ 540–585 Ma and ∼ 440 Ma. Times of intrusion are closely dated by (1) a nearly concordant U–Pb zircon age of 553±2 Ma in diorites of the Creignish Hills pluton; (2) a lower intercept U–Pb zircon age of 540±3 Ma that is within analytical error of 40Ar/39 Ar hornblende plateau isotope-correlation ages of 545 and 550±7 Ma in the River Denys diorite; and (3) an upper intercept U–Pb zircon age of 586±2 Ma in the Melford granitic stock. On the other hand, ∼ 441–455 Ma 40Ar/39 Ar muscovite plateau ages in the host rock adjacent to the Skye Mountain granite provide the best estimate of the time of intrusion, and are consistent with the presence of granitic dykes cutting the Skye Mountain gabbro–diorite previously dated at 438±2 Ma. All the intrusions are calc-alkaline; the Skye Mountain granite is peraluminous. Trace element abundances and Nb and Ti depletions of the intrusive rocks are characteristic of subduction-related rocks. The ∼ 540–585 Ma intrusions form part of an extensive belt running across central Cape Breton Island, and represent the youngest Neoproterozoic arc magmas in this part of Avalonia. Nearby, they are overlain by Middle Cambrian units containing rift-related volcanic rocks, which bracket the transition from convergence to extension between ∼ 540 and 505/520 Ma. This transition varies along the Avalon arc: 590 Ma in southern New England, 560–538 Ma in southern New Brunswick, and 570 Ma in eastern Newfoundland. The bi-directional diachronism in this transition is attributed to northwestward subduction of two mid-ocean ridges bordering an oceanic plate, and the migration of two ridge–trench–transform triple points. Following complete subduction of the ridges, remnant mantle upwelling along the subducted ridges produced uplift, gravitational collapse and the high-temperature/low-pressure metamorphism in the arc in both southern New Brunswick and central Cape Breton Island. The ∼ 440 Ma arc magmatism in the Creignish Hills extends through the Cape Breton Highlands and into southern Newfoundland, and has recently been attributed to northwesterly subduction along the northern margin of the Rheic Ocean.

Lower Silurian subduction-related volcanic rocks in the Chaleurs Group, northern New Brunswick, CanadaGeological Survey of Canada, Contribution No. 2008-0166.Contribution to Natural Resources Canada’s Targeted Geoscience Initiative 3 (2005–2010).

2008 ◽  
Vol 45 (9) ◽  
pp. 981-998 ◽  
Author(s):  
R. A. Wilson ◽  
C. R. van Staal ◽  
S. Kamo
Keyword(s):  
New Brunswick ◽  
Volcanic Rocks ◽  
Zircon Age ◽  
Mafic Rocks ◽  
Fine Grained ◽  
Lower Silurian ◽  
Narrow Width ◽  
Basaltic Flow ◽  
Back Arc

Early Silurian volcanic and subvolcanic rocks are preserved in the lower part of the Chaleurs Group at two locations in northern New Brunswick. At Quinn Point, mafic to intermediate rocks are hosted by sedimentary rocks of the Weir Formation, and at Pointe Rochette, a bed of felsic tuff occurs near the base of the Weir. These rocks are interpreted as the first evidence in New Brunswick of magmatism associated with Late Ordovician – Early Silurian subduction of Tetagouche–Exploits back-arc oceanic crust. At Quinn Point, mafic rocks include a thick basaltic flow or sill and intermediate to mafic cobbles in overlying conglomerate beds. The in situ mafic rocks and the conglomerate clasts are chemically alike and display subduction-related affinities on tectonic discrimination diagrams. At Pointe Rochette, fine-grained felsic tuff contains elevated Th and U and depleted high-field-strength elements, consistent with a subduction-influenced setting, although rare-earth element (REE) abundances are low and the REE profile is relatively flat. A U–Pb (zircon) age of 429.2 ± 0.5 Ma was obtained from the tuff, consistent with the late Llandovery to early Wenlock age of the overlying La Vieille Formation and coinciding with the latter stages of development of the Brunswick subduction complex. Volcanic rocks were emplaced in the arc to arc-trench gap region, probably reflecting local step-back of the magmatic axis due to accretion of continental back-arc ribbons. The low volume of Early Silurian subduction-influenced rocks is probably related to the relatively narrow width of the back-arc basin and the young, “warm” character of back-arc crust.

The Salinic Orogeny in northern New Brunswick: geochronological constraints and implications for Silurian stratigraphic nomenclature1This article is one of a series of papers published in this CJES Special Issue: In honour of Ward Neale on the theme of Appalachian and Grenvillian geology.

2012 ◽  
Vol 49 (1) ◽  
pp. 222-238 ◽  
Author(s):  
Reginald A. Wilson ◽  
Sandra L. Kamo
Keyword(s):  
New Brunswick ◽  
Point Group ◽  
Volcanic Rocks ◽  
Upper Ordovician ◽  
Lower Silurian ◽  
Higher Rank ◽  
Upper Silurian ◽  
Radioisotopic Dating ◽  
Geochronological Constraints ◽  
Back Arc

The Salinic Orogeny is defined to encompass tectonic interactions that affect all elements of Ganderia involved in the closure of the Tetagouche–Exploits back-arc basin between the Late Ordovician and Early Devonian. Hence, the D1 and D2 deformations in the Miramichi Highlands and Elmtree Inlier of northern New Brunswick are Salinic events, and onlap of Lower Silurian rocks onto exhumed parts of the Brunswick Subduction Complex represents the earliest (Salinic A) of three Silurian unconformities in the region. Upper Ordovician to Lower Silurian rocks of the Matapédia successor basin contain widespread evidence of Middle Silurian tectonism (e.g., disconformities, angular unconformities, and fold interference patterns) created by Devonian overprinting of Silurian folds lacking axial planar cleavage (Salinic B). Recent U–Pb radioisotopic dating of chemically abraded zircon from rhyolite just above the Salinic B unconformity has yielded an age of 422.3 ± 0.3 Ma; combined with late Early Silurian fossil ages just below the unconformity, this indicates a ca. 5 million year Middle Silurian hiatus. Finally, Upper Silurian (Ludfordian) rocks are locally disconformably overlain by polymictic conglomerates that form the base of the Devonian section (Salinic C). All Silurian rocks in northeastern New Brunswick have historically been included in the Chaleurs Group; however, unconformities and local stratigraphic variations (especially compared with the type locality) support the introduction of new higher rank names in New Brunswick. Hence, the Quinn Point Group is introduced to incorporate Lower Silurian rocks, the Petit Rocher Group to include Upper Silurian sedimentary rocks in the Nigadoo River Syncline, and the Dickie Cove Group for Upper Silurian volcanic rocks in the Charlo – Jacquet River area. Upper Silurian rocks west of Campbellton that are contiguous with the Chaleurs Group in Quebec, will remain part of the Chaleurs Group.

PALEOENVIRONMENTAL INFERENCES FROM THE CLASSIC LOWER DEVONIAN PLANT-BEARING LOCALITY OF THE CAMPBELLTON FORMATION, NEW BRUNSWICK, CANADA

Palaios ◽  
2012 ◽  
Vol 27 (6) ◽  
pp. 424-438 ◽  
Author(s):  
K. L. KENNEDY ◽  
P. G. GENSEL ◽  
M. R. GIBLING
Keyword(s):  
New Brunswick ◽  
Lower Devonian

Pollen evidence for the postglacial origins of Nova Scotia's forests

1987 ◽  
Vol 65 (6) ◽  
pp. 1163-1179 ◽  
Author(s):  
David G. Green
Keyword(s):  
Nova Scotia ◽  
New Brunswick ◽  
New England ◽  
Ice Sheets ◽  
Arrival Times ◽  
Local Environments ◽  
Pollen Diagrams ◽  
Propagule Dispersal ◽  
Coastal Shelf ◽  
Maritime Canada

Pollen diagrams from sites in southwest Nova Scotia and close to the New Brunswick – Nova Scotia border show that after retreat of the Wisconsin ice sheets, most tree taxa arrived in the extreme southwest of Nova Scotia earlier than anywhere else in the province. For most tree taxa, arrival times at sites in maritime Canada and in northeastern New England are consistent with very early dispersal of individuals along the coastal strip via the exposed coastal shelf and with their entering Nova Scotia from the southwest. These scattered pioneer populations acted as centres for major population expansions, which followed much later in some cases. Local environments, fire, and interspecies competition appear to have been more important than propagule dispersal rates as factors limiting the spread of most taxa.

Petrology and geochemistry of Cambrian volcanic rocks from the Avalon Zone in New Brunswick

1985 ◽  
Vol 22 (6) ◽  
pp. 881-892 ◽  
Author(s):  
John D. Greenough ◽  
S. R. McCutcheon ◽  
V. S. Papezik
Keyword(s):  
New Brunswick ◽  
Volcanic Rocks ◽  
Trace Element Geochemistry ◽  
Element Geochemistry ◽  
Middle Cambrian ◽  
Mafic Rocks ◽  
Rock Types ◽  
Petrology And Geochemistry ◽  
Eastern Seaboard ◽  
Highly Evolved

Lower to Middle Cambrian volcanic rocks occur within the Avalon Zone of southern New Brunswick at Beaver Harbour and in the Long Reach area. The Beaver Harbour rocks are intensely altered, but the major- and trace-element geochemistry indicates that they could be highly evolved (basaltic andesites) within-plate basalts. The mafic flows from the Long Reach area form two chemically and petrologically distinct groups: (1) basalts with feldspar phenocrysts that represent evolved continental tholeiites with some oceanic characteristics; and (2) a group of aphyric basalts showing extremely primitive continental tholeiite compositions, also with oceanic affinities and resembling some rift-related Jurassic basalts on the eastern seaboard. Felsic pyroclastic rocks in the Long Reach area make the suite bimodal. This distribution of rock types supports conclusions from the mafic rocks that the area experienced tension throughout the Early to Middle Cambrian.

Age, chemistry, and tectonic setting of Miramichi terrane (Early Paleozoic) volcanic rocks, eastern and east-central Maine, USA

2021 ◽  
Vol 57 ◽  
pp. 239-273
Author(s):  
Allan Ludman ◽  
Christopher McFarlane ◽  
Amber T.H. Whittaker
Keyword(s):  
New Brunswick ◽  
Subduction Zone ◽  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Calc Alkaline ◽  
East Central ◽  
Arc Volcanism ◽  
Middle Ordovician ◽  
Volcanic Suite ◽  
Back Arc

Volcanic rocks in the Miramichi inlier in Maine occur in two areas separated by the Bottle Lake plutonic complex: the Danforth segment (Stetson Mountain Formation) north of the complex and Greenfield segment to the south (Olamon Stream Formation). Both suites are dominantly pyroclastic, with abundant andesite, dacite, and rhyolite tuffs and subordinate lavas, breccias, and agglomerates. Rare basaltic tuffs and a small area of basaltic tuffs, agglomerates, and lavas are restricted to the Greenfield segment. U–Pb zircon geochronology dates Greenfield segment volcanism at ca. 469 Ma, the Floian–Dapingian boundary between the Lower and Middle Ordovician. Chemical analyses reveal a calc-alkaline suite erupted in a continental volcanic arc, either the Meductic or earliest Balmoral phase of Popelogan arc activity. The Maine Miramichi volcanic rocks are most likely correlative with the Meductic Group volcanic suite in west-central New Brunswick. Orogen-parallel lithologic and chemical variations from New Brunswick to east-central Maine may result from eruptions at different volcanic centers. The bimodal Poplar Mountain volcanic suite at the Maine–New Brunswick border is 10–20 myr younger than the Miramichi volcanic rocks and more likely an early phase of back-arc basin rifting than a late-stage Meductic phase event. Coeval calc-alkaline arc volcanism in the Miramichi, Weeksboro–Lunksoos Lake, and Munsungun Cambrian–Ordovician inliers in Maine is not consistent with tectonic models involving northwestward migration of arc volcanism. This >150 km span cannot be explained by a single east-facing subduction zone, suggesting more than one subduction zone/arc complex in the region.

Paleomagnetism of Lower Devonian volcanics and Devonian dykes from northcentral New Brunswick, Canada

1985 ◽  
Vol 38 (4) ◽  
pp. 262-276 ◽  
Author(s):  
Maurice K.-Seguin ◽  
E. Gahé
Keyword(s):  
New Brunswick ◽  
Lower Devonian
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