scholarly journals Borehole geophysical logs, South Mountain Batholith at Digby and the Wedgeport Granite, Nova Scotia

1997 ◽  
Author(s):  
B E Elliott ◽  
G R Bernius ◽  
P G Killeen
Keyword(s):  
Nova Scotia ◽  
South Mountain Batholith ◽  
Geophysical Logs

Syn-Acadian emplacement model for the South Mountain batholith, Meguma Terrane, Nova Scotia: Magnetic fabric and structural analyses

1997 ◽  
Vol 109 (10) ◽  
pp. 1279-1293 ◽  
Author(s):  
Keith Benn ◽  
Richard J. Horne ◽  
Daniel J. Kontak ◽  
Geoffrey S. Pignotta ◽  
Neil G. Evans
Keyword(s):  
Nova Scotia ◽  
Magnetic Fabric ◽  
The South ◽  
South Mountain Batholith ◽  
Meguma Terrane

40Ar/39Ar dating of micas from the East Kemptville tin deposit, Yarmouth County, Nova Scotia

1985 ◽  
Vol 22 (10) ◽  
pp. 1546-1548 ◽  
Author(s):  
M. Zentilli ◽  
P. H. Reynolds
Keyword(s):  
Nova Scotia ◽  
North America ◽  
Iberian Peninsula ◽  
South Mountain Batholith ◽  
Northwest Africa ◽  
Acadian Orogeny ◽  
Tin Deposit

The East Kemptville tin deposit in Nova Scotia, the largest known tin deposit in North America, lies in a greisen zone within the Davis Lake Pluton, generally considered to be part of the Devonian South Mountain Batholith. Our dating of micas from within the deposit suggests that the greisenization process that accompanied mineralization took place about 295 ± 5 Ma ago, that is, ca. 60 Ma after the emplacement of the batholith.Hydrothermal alteration–mineralization activity in southern Nova Scotia coincided with extensive shearing and tectonism throughout the Hercynian orogen. The East Kemptville deposit appears to be approximately coeval with similar mineralization in southwest England, the Iberian peninsula, and northwest Africa and much younger than the Devonian Acadian orogeny.

Oxygen isotope evidence for the genesis of Upper Paleozoic granitoids from southwestern Nova Scotia

1980 ◽  
Vol 17 (1) ◽  
pp. 132-141 ◽  
Author(s):  
F. J. Longstaffe ◽  
T. E. Smith ◽  
K. Muehlenbachs
Keyword(s):  
Nova Scotia ◽  
Oxygen Isotope ◽  
Large Scale ◽  
The South ◽  
Metasedimentary Rocks ◽  
South Mountain Batholith ◽  
Oxygen Isotope Ratios ◽  
Upper Paleozoic ◽  
Isotope Evidence ◽  
Alteration Processes

The oxygen isotope ratios for 127 rocks and coexisting minerals from Paleozoic granitoids and clastic metasedimentary rocks of southwestern Nova Scotia have been measured. The whole-rock δ18O values for samples of the South Mountain batholith range from 10.1–12.0‰.But discrete granitoid plutons, located to the south of the South Mountain batholith, have lower δ18O values (7.8–10.4‰). Coexisting minerals from the Nova Scotia granitoids are near isotopic equilibrium, indicating that the whole-rock δ18O values primarily reflect the δ18O of the magma, rather than secondary alteration processes. The Meguma Group clastic metasedimentary rocks that host the Nova Scotia granitoids range in δ18O from 10.1–12.9‰. These clastic metasedimentary rocks show no systematic geographic variation in δ18O. The greenschist facies Meguma Group rocks that host the South Mountain batholith have similar δ18O values to the amphibolite facies equivalents located about the southern discrete plutons. Large scale isotopic exchange between the Meguma Group and the South Mountain batholith, or the southern plutons, is not evident.The relatively high δ18O values of the peraluminous South Mountain batholith (10.1–12.0‰) indicate that it formed by anatexis of 18O-rich clastic metasedimentary rocks. The southern plutons were also derived by partial melting of clastic metasedimentary rocks, but their lower δ18O values reflect exchange of the source material with a low 18O reservoir (mafic magmas?) prior to, or during anatexis.The sheared Brenton pluton is much lower in δ18O (5.0‰) than any of the other rocks, probably because of exchange with low 18O fluids during shearing.

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.

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