The age and significance of Carboniferous plutons of the western Cobequid Highlands, Nova Scotia

1989 ◽  
Vol 26 (6) ◽  
pp. 1297-1307 ◽  
Author(s):  
Georgia Pe-Piper ◽  
R. F. Cormier ◽  
David J. W. Piper
Keyword(s):  
Nova Scotia ◽  
Volcanic Rocks ◽  
Older Age ◽  
Ductile Deformation ◽  
Late Devonian ◽  
Crustal Extension ◽  
Eastern Canada ◽  
Appalachian Orogen

A series of granite plutons with minor gabbro–diorite phases outcrops immediately north of the Cobequid Fault in the western Cobequid Highlands, Nova Scotia. The plutons were cut by numerous dykes, and parts of some plutons and some dykes subsequently underwent ductile deformation. Four Rb–Sr whole-rock–K-feldspar isochron dates ranging from 338 to 356 Ma have been obtained from these plutons and the dykes that cut them. The ages of these plutons are indistinguishable from an age of 341 Ma obtained for the nearby Fountain Lake Group volcanic rocks, within estimated uncertainties. Measured Carboniferous granite ages are uncommon in the Appalachian Orogen of eastern Canada. The geochemical character of these plutons indicates that they result from crustal extension. This extension and the compression observed in the granites with ductile deformation are related to transcurrent motion between the Avalon and Meguma terranes along the Minas fault zone.Preliminary Rb–Sr whole-rock data from poorly exposed plutons in the northern part of the Cobequid Highlands suggest a Middle to Late Devonian or older age. These plutons may represent an earlier phase of crustal extension.

An evaluation of crustal assimilation within the Late Devonian South Mountain Batholith, SW Nova Scotia

2012 ◽  
Vol 149 (3) ◽  
pp. 353-365 ◽  
Author(s):  
J. GREGORY SHELLNUTT ◽  
JAROSLAV DOSTAL
Keyword(s):  
Nova Scotia ◽  
Chemical Evolution ◽  
Hydrothermal Fluids ◽  
Eastern North America ◽  
Late Devonian ◽  
Metal Enrichment ◽  
Crustal Assimilation ◽  
South Mountain Batholith ◽  
Appalachian Orogen ◽  
Zircon Saturation

AbstractThe Late Devonian South Mountain Batholith (SMB) of southwestern Nova Scotia is the largest batholith in the Appalachian Orogen of Eastern North America and contains economic deposits of U and Sn. The SMB comprises at least 11 individual plutons, which range in composition from granodiorite to biotite monzogranite, leucomonzogranite and leucogranite. Previous studies have suggested that a combination of fractional crystallization, assimilation of Meguma Supergroup country rocks and an influx of magmatic fluids contributed to the chemical evolution of the SMB. The amount of crustal assimilation is estimated to be as high as 33%. MELTS modelling assuming a starting composition of granodiorite with H2O = 4 wt%, pressure = 4 kbar (~12 km) and fO2 = FMQ can reproduce the chemical evolution observed in the SMB. However, some leucogranites likely require an additional component (e.g. hydrothermal fluids) to explain their alkali metal enrichment (e.g. Na, K, Rb). Zircon saturation thermometry estimates indicate the Salmontail Lake and Scrag Lake granodiorite plutons had high minimum initial temperatures of 823 ± 6°C and 832 ± 2°C, respectively, which are similar to low zircon-inheritance granitoids. The TiO2/Al2O3 and alkali-lime ratios of the surrounding country rocks and the leucogranites indicate the amount of crustal assimilation is likely to be between 10% and 20%. Our findings suggest the granodiorites of the SMB were likely produced by partial melting of the sub-Meguma Supergroup (e.g. Avalon terrane) lower crust caused by the contemporaneous injection of high temperature mafic to ultramafic magmas.

Chronology of Devonian to early Carboniferous rifting and igneous activity in southern Magdalen Basin based on U-Pb (zircon) dating

2002 ◽  
Vol 39 (8) ◽  
pp. 1219-1237 ◽  
Author(s):  
Greg R Dunning ◽  
Sandra M Barr ◽  
Peter S Giles ◽  
D Colin McGregor ◽  
Georgia Pe-Piper ◽  
...  
Keyword(s):  
Nova Scotia ◽  
Fault Zone ◽  
Middle Devonian ◽  
Volcanic Rocks ◽  
Early Carboniferous ◽  
Late Devonian ◽  
Cape Breton Island ◽  
Cape Breton ◽  
Igneous Activity ◽  
Age Determinations

Fifteen U–Pb (zircon) radiometric age determinations have been made on igneous rocks of Middle Devonian to Early Carboniferous age from the southern margin of the Magdalen basin in Cape Breton Island and northern mainland Nova Scotia. Volcanic rocks interbed with early rift-basin sedimentary rocks with some palynological biostratigraphy; dated intrusive rocks cut these sedimentary units. Our biostratigraphically constrained ages are in close agreement with the current Devonian time scale. Combined with previously published data, the age determinations show that igneous activity occurred in four pulses: Middle Devonian (390–385 Ma), early Late Devonian (375–370 Ma), latest Devonian to early Tournaisian (365–354 Ma), and late Tournaisian to early Visean (ca. 339 Ma). Middle Devonian (385–389 Ma) volcanic rocks are confined to the Guysborough Group. The Fisset Brook Formation (basalt and minor rhyolite) in the type area and elsewhere in Cape Breton Island and northern mainland Nova Scotia is Late Devonian (ca. 373 Ma), whereas the biostratigraphically distinct succession at Lowland Cove is younger (365 Ma). These Late Devonian rocks are synchronous with plutonism in the Cape Breton Highlands and the Meguma terrane. In the Cobequid Highlands, rhyolite of the Fountain Lake Group was synchronous with Horton Group deposition and with widespread granite plutons (362–358 Ma) emplaced during shear on the Cobequid fault zone. The overlying Diamond Brook Formation basalts are slightly younger (355 Ma). Late Tournaisian – early Visean mafic intrusions and minor basalt occur along the Cobequid – Chedabucto fault zone and in a belt from southern New Brunswick through Prince Edward Island to southwestern Cape Breton Island.

Carabidae (Coleoptera) in Nova Scotia, Canada wild blueberry fields: prospects for biological control

2012 ◽  
Vol 144 (6) ◽  
pp. 779-791 ◽  
Author(s):  
G.C. Cutler ◽  
J.M. Renkema ◽  
C.G. Majka ◽  
J.M. Sproule
Keyword(s):  
Biological Control ◽  
Nova Scotia ◽  
Species Diversity ◽  
Insect Pests ◽  
Abundant Species ◽  
Conservation Biological Control ◽  
Carabid Beetles ◽  
Eastern Canada ◽  
Wild Blueberries ◽  
Wild Blueberry

AbstractThe Carabidae (Coleoptera) are a diverse family of beetles with almost 300 species identified in Nova Scotia, Canada. Carabid beetle communities have been studied in several agricultural systems, but not wild blueberries, an important crop in eastern Canada. In the interest of potentially developing conservation biological control programs in wild blueberry, we collected Carabidae in crop (fruit-bearing) and sprout (vegetative) blueberry fields in Nova Scotia in order to assess species diversity and abundance over space and time. Over 3200 specimens were collected, representing 51 species. A large portion of collected specimens (39%) were nonnative, and the most abundant species were generally predacious and synanthropic. Species diversity tended to be higher near forest edges than further into fields, but not for all abundant species. Several of the most prominent predators showed significant differences in preference of crop versus sprout fields, distribution throughout fields, and seasonable abundance. These findings have implications for conservation biological control efforts with carabid beetles against several insect pests in wild blueberry.

scholarly journals A New Look at Cultivar Preference in Hoplocampa testudinea (Hymenoptera: Tenthredinidae) on Apple in the Annapolis Valley of Nova Scotia, Canada

Insects ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 769
Author(s):  
Suzanne Blatt ◽  
Kim Hiltz
Keyword(s):  
Nova Scotia ◽  
Physicochemical Properties ◽  
Larval Survival ◽  
Larval Performance ◽  
Differential Survival ◽  
Eastern Canada ◽  
Weak Evidence ◽  
Important Pest ◽  
Annapolis Valley ◽  
Hoplocampa Testudinea

(1) Background: The European apple sawfly, Hoplocampa testudinea Klug (Hymenoptera: Tenthredinidae), can be an economically important pest in eastern Canada and shows preference for apple cultivars in Nova Scotia, Canada. We hypothesized that this preference could be due to oviposition by female H. testudinea (preference-performance hypothesis) during the bloom period or differential larval survival during development due to fruitlet physicochemical properties. (2) Methods: Fifteen commercial and experimental apple (Malusdomestica Borkh.; Rosaceae) cultivars located at the Kentville Research and Development Centre (Kentville, Nova Scotia) were chosen and examined for H. testudinea oviposition, larval performance during fruitlet development, fruitlet physicochemical properties and damage assessment at harvest from 2016–2019, inclusive. (3) Results: H. testudinea showed significant cultivar preference during oviposition, during development and at harvest, but the ranking of these cultivars was not the same throughout the season. Total impact by H. testudinea was consistent for most cultivars over multiple years of the study. (4) Conclusion: Correlation of oviposition with damage provided weak evidence for the preference-performance hypothesis. We propose that this relationship is weak due to differential survival of larvae during development.

scholarly journals The Nordre Strømfjord shear zone and the Arfersiorfik quartz diorite in Arfersiorfik, the Nagssugtoqidian orogen, West Greenland

2006 ◽  
Vol 11 ◽  
pp. 145-162 ◽  
Author(s):  
Kai Sørensen ◽  
John A. Korstgård ◽  
William E. Glassley ◽  
Bo Møller Stensgaard
Keyword(s):  
Shear Zone ◽  
Volcanic Rocks ◽  
Quartz Diorite ◽  
Ductile Deformation ◽  
Chemical Compositions ◽  
West Greenland ◽  
South West ◽  
Wide Range ◽  
Inland Ice ◽  
Zone Deformation

The Nordre Strømfjord shear zone in the fjord Arfersiorfik, central West Greenland, consists of alternating panels of supracrustal rocks and orthogneisses which together form a vertical zone up to 7 km wide with sinistral transcurrent, ductile deformation, which occurred under middle amphibolite facies conditions. The pelitic and metavolcanic schists and paragneisses are all highly deformed, while the orthogneisses appear more variably deformed, with increasing deformation evident towards the supracrustal units. The c. 1.92 Ga Arfersiorfik quartz diorite is traceable for a distance of at least 35 km from the Inland Ice towards the west-south-west. Towards its northern contact with an intensely deformed schist unit it shows a similar pattern of increasing strain, which is accompanied by chemical and mineralogical changes. The metasomatic changes associated with the shear zone deformation are superimposed on a wide range of original chemical compositions, which reflect magmatic olivine and/ or pyroxene as well as hornblende fractionation trends. The chemistry of the Arfersiorfik quartz diorite suite as a whole is comparable to that of Phanerozoic plutonic and volcanic rocks of calc-alkaline affinity.

Degree-day models to predict carrot weevil (Coleoptera: Curculionidae) emergence and oviposition in Nova Scotia, Canada

2020 ◽  
Vol 152 (3) ◽  
pp. 374-388
Author(s):  
Suzanne Blatt ◽  
Deney Augustine Joseph ◽  
G. Christopher Cutler ◽  
A. Randall Olson ◽  
Scott White
Keyword(s):  
Nova Scotia ◽  
Adult Emergence ◽  
Hill Equation ◽  
Base Temperature ◽  
Degree Days ◽  
Eastern Canada ◽  
Leaf Stage ◽  
True Leaf ◽  
Listronotus Oregonensis ◽  
Carrot Weevil

AbstractCarrot weevil, Listronotus oregonensis (LeConte) (Coleoptera: Curculionidae), is a pest of carrot (Daucus carota var. sativus Hoffmann; Apiaceae) throughout eastern Canada. Carrot weevil emergence and oviposition were monitored in commercial carrot fields in Nova Scotia. Cumulative degree days were calculated using a base temperature of 7 °C (DD7), and models were developed to predict cumulative emergence and oviposition using nonlinear regression. Cumulative emergence and oviposition were adequately explained as functions of DD7 by a three-parameter sigmoidal Hill equation. Our emergence model predicted initial and peak adult emergence at 35 and 387 DD7, respectively, with oviposition on carrot baits occurring as early as 42 DD7. Models were then validated to evaluate how well they performed. Oviposition on carrot plants began at the fourth true-leaf stage (342 DD7) and continued until eleventh true-leaf stage. Growers using these models can identify their window of opportunity to manage their carrot weevil populations targeting the majority of emerged adults before oviposition begins in the field.

scholarly journals Two Amelanistic Eastern Red-backed Salamanders (Plethodon cinereus) from Eastern Canada

2011 ◽  
Vol 125 (1) ◽  
pp. 58 ◽  
Author(s):  
Jean-David Moore ◽  
John Gilhen
Keyword(s):  
Nova Scotia ◽  
Plethodon Cinereus ◽  
Eastern Canada ◽  
Black Skin ◽  
Colour Morphs ◽  
Skin Pigment

Three colour morphs of the Eastern Red-backed Salamander, Plethodon cinereus, are known in eastern Canada: red-backed, lead-backed, and erythristic. Anomalies, including two albino and four leucistic individuals, are also known from eastern Canada. We report the first salamander individuals exhibiting amelanism, which is a lack of black skin pigment, but with black eyes, one from Quebec and one from Nova Scotia, Canada.

The late Neoproterozoic Frog Lake hornblende gabbro pluton, Avalon Terrane of Nova Scotia: evidence for the origins of appinites

2010 ◽  
Vol 47 (2) ◽  
pp. 103-120 ◽  
Author(s):  
Georgia Pe-Piper ◽  
David J.W. Piper ◽  
Basilios Tsikouras
Keyword(s):  
Nova Scotia ◽  
Country Rock ◽  
Volcanic Rocks ◽  
Mafic Magma ◽  
Single Type ◽  
Structural Level ◽  
Element Abundances ◽  
Hornblende Gabbro ◽  
Late Neoproterozoic ◽  
Low K

The late Neoproterozoic Frog Lake pluton, in the Avalon terrane of the Cobequid Highlands, Nova Scotia, consists predominantly of hornblende gabbro. It shows petrographic similarities to water-rich mafic intrusions known as appinites that are present in some collisional orogens. This study aims to further understanding of the origin of appinitic intrusions. In the field, the main hornblende gabbro was intruded between screens of metasedimentary country rock that is of upper greenschist metamorphic grade. The contacts appear to have been pathways for magma of gabbroic, tonalitic–granodioritic, and granitic composition that carried enclaves of gabbroic lithologies. Some of these magmas had a high volatile content, resulting in abundance of hydrous mineral phases, pegmatites, and diffuse felsic segregations. These varied rocks in the contact zones experienced progressive shear resulting in syn-magmatic deformation. Low-Ti hornblende gabbros have trace-element abundances similar to subduction-related low-K mafic rocks, including some enrichment in large-ion lithophile elements and marked relative depletion in Nb and Y. High-Ti hornblende gabbros and pyroxene–mica gabbro show more alkaline characteristics, with higher amounts of Nb, Y, P2O5, and high-field-strength elements. Tonalite and granite veins are geochemically similar to volcanic-arc granite. Comparison with appinites in the literature suggests that the Frog Lake pluton represents a deeper structural level than most appinites. The Frog Lake appinites were part of the feeder system to back-arc volcanic rocks of the Jeffers Group. Comparison with other appinites also leads to the conclusion that there is not a single type of “appinitic magma”: different appinitic plutons range in composition from low-K calc-alkaline to shoshonitic. The essential characteristic is a water-rich mafic magma. Appinites occur in settings undergoing crustal-scale strike-slip shear, where the faults allow rapid rise of mafic magma to shallow crustal levels.

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