| Titre | U-Pb geochronology and lithogeochemistry of the host rocks to the Reid gold deposit, Exploits Subzone-Mount Cormack Subzone boundary area, central Newfoundland |
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| Auteur | Sandeman, H; McNicoll, V; Evans, D T W |
| Source | Newfoundland and Labrador, Department of Natural Resources, Geological Survey, Report, Current Research 12-1, 2012 p. 85-102  Accès ouvert |
| Liens | Online - En ligne
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| Image |  |
| Année | 2012 |
| Séries alt. | Secteur des sciences de la Terre, Contribution externe 20140471 |
| Éditeur | Newfoundland and Labrador Department of Natural Resources |
| Document | publication en série |
| Lang. | anglais |
| Media | en ligne; numérique |
| Formats | pdf |
| Province | Terre-Neuve-et-Labrador |
| SNRC | 2D/05 |
| Région | Gander River |
| Lat/Long OENS | -56.0000 -55.5000 48.5000 48.2500 |
| Sujets | gisements minéraux; lithogéochimie; roches granitiques; datations au uranium-plomb; datations radiométriques; trondhjémites; minéralisation; datations au zircon; altération; gisements porphyriques; trous
de forage; carottes; analyses géochimiques; Sous-Zone d'Exploits ; géochronologie; minéraux métalliques; Ordovicien; Cambrien |
| Illustrations | cartes géologiques généralisées |
| Programme | Initiative géoscientifique ciblée (IGC-4) Étude des gîtes porphyriques |
| Diffusé | 2012 01 01 |
| Résumé | (disponible en anglais seulement)
The Reid gold deposit of the Brady option exploration licences in NTS map area 2D/05 of central Newfoundland was discovered
in 2002, through prospecting and
sampling of arsenopyrite-bearing quartz-plagioclase porphyry float, in an area of
extensive till cover, immediately north of the Northwest Gander River. Reid deposit mineralization is hosted in ophiolitic
basalt, diabase dykes and trondhjemite
of the Coy Pond Complex that likely occur in a series of thrust-bound slices, marking
the boundary between the eastern Exploits Subzone (Dunnage Zone) and the ellipsoidal Mount Cormack Subzone, a tectonic
window into the underlying Gander Zone.
Trench and drillcore data indicate that the Reid deposit mineralization occurs as
randomly oriented sericite-chlorite-Fe-carbonate-pyrite-arsenopyrite alteration, hosted mainly in silicified and quartzveined,
quartz-plagioclase porphyritic
granitoid (Reid porphyry) and to a lesser extent, in basalt, diabase and microgabbro
of the Coy Pond Complex. The porphyry both crosscuts, and is intruded by fine-grained diabase and basalt. Lithogeochemical
data for the porphyry, diabase and
lava indicate that these are all tholeiitic, trace-element depleted, supra-subduction zone
rocks. The Reid (deposit) porphyry is a trondhjemite and likely represents the final product of fractional crystallization of
strongly depleted
tholeiitic mafic rocks of the ophiolite complex.
The U-Pb zircon geochronology indicates the Reid (deposit) trondhjemite crystallized in the Cambrian at 510 ± 4 Ma
and the Coy Pond Complex is, therefore, the oldest known ophiolite fragment in
the Appalachian-Caledonide orogen. |
| GEOSCAN ID | 295884 |
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