Geochemistry of the tonalitic and granitic rocks of the Nova Scotia southern plutons

Albuquerque, Carlos A.R. De

doi:10.1016/0016-7037(77)90183-1

Cited by 28 publications

(5 citation statements)

References 42 publications

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“…Mafic intrusions that could be genetically related to the SMB have not been found within the batholith, but do occur around its periphery. These are volumetrically minor dykes and plugs in southwestern Nova Scotia (de Albuquerque, 1977;Rogers, 1985;Douma, 1988)) but there are more important gabbroic breccia pipes spatially associated with the nearby Liscomb Complex (Giles and Chatterjee, 1986). These may yet be shown to be extremely important in the magmatic evolution of the Meguma Zone, but at present the evidence is only embryonic.…”

Section: Source Of the Granodiorite Magmamentioning

confidence: 99%

Neodymium and strontium isotopic constraints on the origin of the peraluminous granitoids of the South Mountain Batholith, Nova Scotia, Canada

Clarke

Halliday

Hamilton

1988

Chemical Geology: Isotope Geoscience section

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Nd isotopic data from the South Mountain batholith show that ita peraluminous granitic rocks have considerably higher thd (t=372 Ma) values (-5.2 to-1.4) than the extensive flyschoid country rocks (-11.2 to-8.7). These isotopic data are combined with Sr isotopic measurements to estimate the involvement of the country rocks, either as source materials or as contaminants, in the batholith. Metasedimentary enclaves in the batholith generally have Nd and Sr isotopic compositions intermediate between those of the batholith and the country rocks, and provide evidence of contamination by the country rocks. Integrated with other geochemical data, the isotopic results show at least two possible origins for the South Mountain batholith: either this large batholith is a hybrid of mantle and crustal materials and contains a large proportion of mantle-derived Nd and Sr, or the magma is derived from deeper metasedimentary crustal material, with younger model ages or higher Sm/Nd ratios than the upper crust.

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Section: Source Of the Granodiorite Magmamentioning

confidence: 99%

Neodymium and strontium isotopic constraints on the origin of the peraluminous granitoids of the South Mountain Batholith, Nova Scotia, Canada

Clarke

Halliday

Hamilton

1988

Chemical Geology: Isotope Geoscience section

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“…Three plot in the granodiorite field; one, at the right edge of the syenogranite subfield, and the rest plot in the monzogranite subfield. Albuquerque (1977) identified samples 357 and 358 as muscovite-biotite granodiorite which is confirmed by their low K-spar/plagioclase ratios, and Grant and others (1980) recognized that sample 222, which is the average of 16 modal analyses of stained samples, plots as a granodiorite. Sample 222 is rather surprising because the other samples from Stone Mountain, 101, 102 and 103 which are the averages of 4 f 49 and 6 modal analyses, respectively, plot as monzogranites, and megascopically Stone Mountain granite appears to be of uniform composition.…”

Section: Alkali Feldspars Pl Agiocl Asementioning

confidence: 87%

Two-mica granites; Part A, Their occurrence and petrography

Armstrong¹,

Boudette²

1984

Open-File Report

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Classical European Hercynian two-mica granites host or are genetically related to tin, tungsten and uranium deposits. Similar rocks elsewhere in the world are associated with similar ore deposits, and a knowledge of two-mica granites can be a useful exploration tool.Two-mica granites occur usually as small plutons late in a plutonic sequence that intrudes high-grade metamorphic rocks of an orogen. In plan they are elongate or eliptical and in three dimensions they are tabular or sheet-like. They are usually leucocratic, massive, hypidiomorphic granular granitoids that consist of about 31 volume percent quartz, 26 percent K-spar, 31 percent plagioclase and about 10 percent mica in which muscovite may exceed biotite. In some, muscovite is absent in which event total mica is about 5 percent, except for a few types that contain abundant biotite. In two-mica granites hornblende is absent, magnetite is sparse, and sphene is rare. Common accessory minerals are apatite, zircon, monazite, garnet, and tourmaline.Two-mica granitoids are more similar to S-type and ilmenite-series granitoids of Chappell , and White (1974) and Ishihara (1977), respectively, than to their I-type and magnetite-series granitoids. Modal plots of two-mica granitoids fall predominantly in the monzogranite subfield of Streckeisen's (1976) modal classification of granitoids. Modal plots, however, do not uniquely define two-mica granites.

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“…3. REE spectra for granites samples in this study compared with fields for Shelbume granites and granodiorite (de Albuquerque 1977) and South Mountain granodiorite (Muecke and Clarke 1981). Zr and Th compared with other cores analyzed in this study. Core 21 shows a more highly fractionated rare-earth-element (REE) spectrum, with a larger Eu anomaly, than core 20 ( Fig.…”

Section: Shelburne Granitementioning

confidence: 98%

Offshore continuation of Meguma Terrane, southwestern Nova Scotia

Pe‐Piper¹,

Loncarevic²

1989

Can. J. Earth Sci.

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Eight short drill cores have been examined from the continental shelf southwest of Nova Scotia. Four cores recovered granitoid rocks of two types. Ilmenite-bearing granitoid rocks petrographically and geochemically resemble granodiorites of the South Mountain Batholith and granites of the Seal Island Pluton. Magnetite-bearing granitoid rocks are also peraluminous but have no exact analogues onshore in Nova Scotia. Two cores recovered metamorphic rocks in a small area 50 km south of Seal Island. One consits of chlorite-muscovite-quartz schist, geochemically similar to rocks of the Halifax Formation. The second sampled epidote-chlorite-quartz schist similar to metavolcanic rocks of the White Rock Formation. One further core sampled quartzite, and another sampled a metavolcanic rock (possibly erratic).The regional extent of these lithotypes can be inferred from gravity and aeromagnetic data. Regional gravity data suggest the presence of a large granite body off southwestern Nova Scotia. In this area, magnetic anomalies are irregular, apparently reflecting the presence of magnetite-bearing granites. The layer-stripping method of analyzing the magnetic field shows that the area is underlain at depth by high magnetic anomalies. Large near-surface linear magnetic anomalies are used to map the extent of the volcanic rocks of the White Rock Formation. The area is cut by several northwest-trending faults that postdate Acadian folding but predate the earliest Jurassic magmatism of the Shelburne Dyke and North Mountain basalt. The unusual magnetic signature of the area off southwestern Nova Scotia may reflect a different basement; it is possible that Meguma rocks are thrust over the Avalon Terrane. Alternatively, it may be solely the result of magnetite-bearing granites. These granites may be related to a Permian thermal event in southwest Nova Scotia, and they have some petrographic similarity to young granites of the Piedmont Zone of South Carolina.On a examink huit carottes de forage de longueur restreinte pr6levCes sur la plate-forme au sud-ouest de la ~ouvelle-~cosse. Parmi elles, quatre sont constitutkes de roches granitoides de deux types diffkrents. Un premier type contient de I'ilmCnite, et sa composition petrographique et geochimique est analogue a celle des granodiorites du batholite de South Mountain et des granites du pluton de Seal Island. Ledeuxikme type, Cgalement peralumineux, renferme de la magnCtite, cependant il n'existe pas sur le temtoire de la Nouvelle-Ecosse des roches exactement analogues. Les roches mCtamorphiques sont repksentCes dans deux carottes pklevkes dans une petite kgion situCe a 50 km au sud du Seal Island. Une est formCe d'un schiste chlorite -muscovite-quartz, gCochimiquement semblable a celui de la Formation d'Halifax, l'autre est constituke d'un schiste 2 1 Cpidote -chlorite -quartz ressemblant aux roches volcaniques de la Formation de White Rock. Les deux autres carottes sont formCes respectivement d'un quartzite et d'une mCtavolcanite (possiblement erratique).Les ltvts gravimCtriques...

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Geochemistry of the tonalitic and granitic rocks of the Nova Scotia southern plutons

Cited by 28 publications

References 42 publications

Neodymium and strontium isotopic constraints on the origin of the peraluminous granitoids of the South Mountain Batholith, Nova Scotia, Canada

Neodymium and strontium isotopic constraints on the origin of the peraluminous granitoids of the South Mountain Batholith, Nova Scotia, Canada

Two-mica granites; Part A, Their occurrence and petrography

Offshore continuation of Meguma Terrane, southwestern Nova Scotia

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