The position and nature of the Gander–Avalon boundary, southern New Brunswick, based on geochemical and isotopic data from granitoid rocks

1996 ◽  
Vol 33 (2) ◽  
pp. 129-139 ◽  
Author(s):  
Joseph B. Whalen ◽  
Leslie R. Fyffe ◽  
Frederick J. Longstaffe ◽  
George A. Jenner
Keyword(s):  
Nova Scotia ◽  
New Brunswick ◽  
Boundary Zone ◽  
Isotopic Data ◽  
Volcanic Arc ◽  
Isotopic Signatures ◽  
Basement Rocks ◽  
Granitoid Rocks ◽  
T Values ◽  
Canadian Appalachians

In southern New Brunswick, the Gander–Avalon boundary is obscured by boundary-parallel faults and various cover sequences. Siluro-Devonian granites, which intrude unequivocal Gander or Avalon rocks, display exclusively negative (−1.9 ± 1.0) and positive (+1.9 ± 0.7) εNd(T) signatures, respectively. Such contrasting Nd isotopic signatures, combined with other geochemical differences between plutons, are potentially valuable tools for terrane analysis. Nine small Devonian plutons intruding the boundary zone fall into contrasting geochemical groups with (La/Lu)N <4 and >4. The former are topaz-bearing granites, while the latter are volcanic-arc-type granites. Except for one pluton, with an εNd(T) signature of –2.0, εNd(T) values range from –0.4 to +0.7, spanning the gap between "type" Avalon and "type" Gander plutons. These results suggest the plutons sampled either (i) stratigraphically overlapping or tectonically interleaved Gander and Avalon basement rocks, or (ii) a distinct basement source beneath the boundary zone. Our results demonstrate that the Gander–Avalon boundary in southern New Brunswick is not a simple throughgoing crustal fault, and that the Gander and Avalon zones are underlain by different continental basement blocks. Comparison with results from Newfoundland and Nova Scotia suggests that these basement blocks are continuous throughout the Canadian Appalachians.

Geochemistry of the Namurian Lismore Formation, northern mainland Nova Scotia: sedimentation and tectonic activity along the southern flank of the Maritimes Basin

1999 ◽  
Vol 36 (10) ◽  
pp. 1655-1669 ◽  
Author(s):  
Jacquelyn E Stevens ◽  
J Brendan Murphy ◽  
Fred W Chandler
Keyword(s):  
Nova Scotia ◽  
Tectonic Activity ◽  
Isotopic Data ◽  
Rock Fragments ◽  
Metasedimentary Rocks ◽  
Clastic Rocks ◽  
Granitoid Rocks ◽  
Maritimes Basin ◽  
Group B ◽  
Southern Flank

Geochemical and isotopic data from the clastic rocks of the Namurian Lismore Formation in mainland Nova Scotia identify key episodes of tectonic activity during the development of the Maritimes Basin in Atlantic Canada. The Lismore Formation forms part of the Mabou Group and is an upward-coarsening 2500 m thick fluvial sequence deposited in the Merigomish sub-basin along the southern flank of the Maritimes Basin. Based on stratigraphic evidence, the Lismore Formation can be divided into upper and lower members which reflect variations in depositional environment and paleoclimate. The geochemical and isotopic data may also be subdivided into two groupings that primarily reflect varying contributions from accessory phases, clay minerals, or rock fragments. This subdivision occurs 115 m above the base of the upper member. The data from the lower grouping (group A) show an important contribution from underlying Silurian rocks, with a relatively minor contribution from Late Devonian granitoid rocks from the adjacent Cobequid Highlands and possibly metasedimentary rocks from the Meguma Terrane to the south. The data from the upper grouping (group B) reveal a more important contribution from the Cobequid Highlands granitoid rocks. This variation in geochemistry is thought to constrain the age of renewed motion and uplift along the faults along the southern flank of the Maritimes Basin and, more generally, suggests that geochemical and isotopic data of continental clastic rocks may help constrain the age of tectonic events that influence deposition of basin-fill rocks.

scholarly journals U-Pb (zircon) age for the Beaver Harbour Porphyry, New River belt, southern New Brunswick, Canada

2014 ◽  
Vol 50 ◽  
pp. 155
Author(s):  
Sandra M. Barr ◽  
Cameron J. Bartsch ◽  
Brent V. Miller ◽  
Chris E. White
Keyword(s):  
New Brunswick ◽  
Continental Margin ◽  
Active Continental Margin ◽  
Chemical Data ◽  
Volcanic Arc ◽  
Zircon Age ◽  
Isotopic Signatures ◽  
Southern Margin ◽  
High Level

The Beaver Harbour Porphyry is a high-level intermediate to felsic granitoid and locally tuffaceous unit with quartz and less abundant feldspar phenocrysts. It forms a fault-bound sliver along the southern margin of the New River belt in southern New Brunswick. A concordant TIMS U-Pb (zircon) age of 551 ± 1.2 Ma shows that the porphyry is of the same age as other high-level plutonic and volcanic units that form most of the New River belt. Chemical data show that these units likely formed in a volcanic-arc environment at an active continental margin. One sample from the porphyry has ƐNd(t) of -0.5, within the range of other samples from the New River belt and consistent with the interpretation that the belt is part of Ganderia, rather than Avalonia, which generally has more juvenile isotopic signatures.

scholarly journals Field relations and petrology of the Trafalgar Plutonic Suite and comparisons with other Devonian granitoid plutons in the Meguma terrane, Nova Scotia, Canada

2020 ◽  
Vol 56 ◽  
pp. 001-017
Author(s):  
Raya C. Puchalski ◽  
Sandra M. Barr ◽  
Chris E. White
Keyword(s):  
Nova Scotia ◽  
Quartz Diorite ◽  
Chemical Characteristics ◽  
Volcanic Arc ◽  
Mafic Rocks ◽  
Metasedimentary Rocks ◽  
Mafic Intrusions ◽  
Coarse Texture ◽  
Granitoid Rocks ◽  
Meguma Terrane

The Trafalgar Plutonic Suite intruded metasedimentary rocks of the Goldenville and Halifax groups in the northeastern part of the Meguma terrane of southern Nova Scotia at about 374 Ma, based on previously published U–Pb and 40Ar/39Ar mineral ages. Using field and petrographic observations, the suite is divided into 20 different plutons on the combined basis of variations in grain size (fine, medium, or coarse), texture (equigranular or porphyritic) and modal mineralogy (quartz diorite/tonalite, granodiorite, monzogranite, and syenogranite). The granodiorite, monzogranite, and syenogranite plutons are relatively uniform in composition with little variation in mineralogy or chemistry within each pluton or between plutons of the same lithology. In contrast the quartz diorite/tonalite plutons show mineralogical and chemical variation, both within and between plutons. The granodiorite, monzogranite, and syenogranite plutons closely resemble other peraluminous granitoid plutons characteristic of the Meguma terrane. The quartz diorite/tonalite plutons are varied but chemically resemble minor Devonian mafic intrusions elsewhere in the Meguma terrane. Like other plutons of the Meguma terrane, the Trafalgar Plutonic Suite has chemical characteristics of volcanic-arc to syn-collisional granitoid rocks and likely has experienced extensive contamination by metasedimentary material as documented by previous studies of plutons in the Meguma terrane. The minor quartz diorite/tonalite plutons are additional examples of the mafic rocks that have been proposed in tectonic models of the Meguma terrane to have facilitated melting of the lower crust to generate granodioritic parent magmas, followed by crystal fractionation and extensive contamination by metasedimentary material.

Grenvillian basement in the northern Cape Breton Highlands, Nova Scotia

1987 ◽  
Vol 24 (5) ◽  
pp. 992-997 ◽  
Author(s):  
Sandra M. Barr ◽  
Robert P. Raeside ◽  
Otto van Breemen
Keyword(s):  
Nova Scotia ◽  
Long Range ◽  
Granitic Rocks ◽  
Cape Breton Island ◽  
Cape Breton ◽  
Basement Rocks ◽  
Northern Cape ◽  
Granitoid Rocks

The northernmost Cape Breton Highlands are underlain by the Blair River Complex, a distinctive assemblage of basement rocks including felsic and mafic gneisses, foliated gabbroic to granitic rocks, anorthosite, and foliated and unfoliated varieties of syenite. Major faults and mylonite zones separate the complex from schists, gneisses, and granitoid rocks typical of the rest of the Cape Breton Highlands. U–Pb dating of zircon from the Lowland Brook syenite of the Blair River Complex indicates a metamorphic age of [Formula: see text] and an igneous age of 1100–1500 Ma. These ages and the distinctive rock assemblage allow the Blair River Complex to be correlated with the Grenvillian rocks in the Long Range Inlier and Indian Head Range Complex of western Newfoundland. This is the first confirmed report of Grenvillian basement in Cape Breton Island, and it places new constraints on correlations between Newfoundland and the northern mainland Appalachians.

Organochlorine Residues in Brook Trout and Yellow Perch From New Brunswick and Nova Scotia (Canada) Lakes

1987 ◽  
Vol 22 (3) ◽  
pp. 352-364
Author(s):  
R. Peterson ◽  
S. Ray
Keyword(s):  
Nova Scotia ◽  
New Brunswick ◽  
Brook Trout ◽  
Yellow Perch ◽  
Intensive Agriculture ◽  
Fish Tissues ◽  
North Central ◽  
Ddt Metabolites ◽  
Headwater Lakes

Abstract Brook trout and yellow perch collected while surveying New Brunswick and Nova Scotia headwater lakes were analyzed for DDT metabolites, chlordane, hexacyclohexane isomers, hexachlorobenzene, toxaphene and PCB’s. Concentrations of DDT metabolites were much higher from fish taken from lakes in north-central N.B. (200-700 ng/g wet wt) than from fish taken elsewhere (&lt;10 ng/g). Seventy to 90% of the DDT metabolites was DDE. Chlordane (3-13 ng/g) was analyzed in seven trout, six of them from central N.B. areas with intensive agriculture. Isomers of hexachlorocyclohexane were in highest concentration from north-central N.B. (10-20 ng/g), eastern N.S. (5-15 ng/g) and southern N.B. (5-20 ng/g). In most cases, alpha-hexachlorocyclohexane (lindane) was the isomer in highest concentration. Concentrations of hexachlorobenzene in fish tissues was highly variable with no obvious geographic bias. PCB’s were detected in very few fish, and no toxaphene was detected.

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.

PREDATION BY INSECTS AND SPIDERS INHABITING COLONIAL WEBS OF HYPHANTRIA CUNEA

1972 ◽  
Vol 104 (8) ◽  
pp. 1197-1207 ◽  
Author(s):  
R. F. Morris
Keyword(s):  
Population Dynamics ◽  
Nova Scotia ◽  
North America ◽  
Population Density ◽  
New Brunswick ◽  
Numerical Response ◽  
Initial Number ◽  
Hyphantria Cunea ◽  
The North ◽  
The Mean

AbstractThe number of predators inhabiting nests of Hyphantria cunea Drury was recorded annually for 13 years in four areas in New Brunswick and two areas on the coast of Nova Scotia. The most common groups were the pentatomids and spiders, which sometimes reproduced within the nests, but the mean number per nest was low in relation to the number of H. cunea larvae in the colonies. The rate of predation on fifth-instar larvae was low. Small or timid predators appeared to prey largely on moribund larvae or small saprophagans during the principal defoliating instars of H. cunea.No relationship could be detected between the number of larvae reaching the fifth instar and the number of predators in the colony; nor could any functional or numerical response of the predators to either the initial number of larvae per colony or the population density of colonies be found. It is concluded that the influence of the nest-inhabiting predators is small and relatively stable, and may be treated as a constant in the development of models to explain the population dynamics of H. cunea.H. cunea is a pest in parts of Europe and Asia, where it has been accidentally introduced from North America. The introduction to other continents of the North American predator, Podisus maculiventiis (Say), is discussed briefly.

Limnetic Zooplankton Assemblages in Atlantic Canada with Special Reference to Acidification

1986 ◽  
Vol 43 (2) ◽  
pp. 444-456 ◽  
Author(s):  
J. C. H. Carter ◽  
W. D. Taylor ◽  
R. Chengalath ◽  
D. A. Scruton
Keyword(s):  
Nova Scotia ◽  
New Brunswick ◽  
Fish Predation ◽  
Low Ph ◽  
Buffering Capacity ◽  
The Other ◽  
Bay Of Fundy ◽  
Factor Scores ◽  
Multiple Discriminant Analysis ◽  
Biological Factors

Crustacean and rotifer plankton assemblages of 93 lakes in Labrador, 107 in Newfoundland, and 142 in New Brunswick – Nova Scotia were investigated for evidence of correlations with lake morphometric, chemical, or biological factors. Labrador assemblages were almost completely lacking in identifiable structure. Newfoundland species clustered into two groups of different body size, suggesting the influence of fish predation. Only one species in Labrador and Newfoundland was significantly correlated with a derived factor related to lake water buffering capacity. New Brunswick – Nova Scotia species clustered into two groups, one featuring significant positive and the other significant negative correlations with the buffering factor. From this we conclude that acidification is having an impact on the limnetic zooplankton of these two provinces. Multiple discriminant analysis was used to demonstrate that New Brunswick – Nova Scotia lakes differing in their buffering capacity were also distinct in zooplankton composition. Lakes with low factor scores (low pH, alkalinity, and calcium) were mainly located in the Bay of Fundy region; this area has above average fog and precipitation, and lies within the summer air flow carrying pollutants from the south.

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