GEOSCAN, résultats de la recherche


TitreThe south Newfoundland granophile mineral district: features and opportunities for research on blind deposits
AuteurKerr, A
SourceL'Association géologique du Canada-L'Association minéralogique du Canada, Réunion annuelle conjointe, Recueil des résumés vol. 37, 2014 p. 137-138
LiensOnline - En ligne (PDF 8.75 MB)
RéunionGAC-MAC Joint annual meeting; Fredericton, NB; CA; mai 2014
Documentpublication en série
Mediaen ligne; numérique
Référence reliéeCette publication est reliée Kerr, A; (2015). The south Newfoundland granophile mineral district: features and opportunities for research on blind deposits, TGI 4 - Intrusion Related Mineralisation Project: new vectors to buried porphyry-style mineralisation, Commission géologique du Canada, Dossier public 7843
SNRC11P/13; 11P/14; 11P/15; 11P/16
Lat/Long OENS-58.0000 -56.0000 48.0000 47.7500
Sujetsgîtes magmatiques; gisements minéraux; gîtes granophyriques; tungstène; spath fluor; molybdène; roches granitiques; datations au uranium-plomb; datations radiométriques; altération hydrothermale; géochronologie; minéraux métalliques; Dévonien
ProgrammeÉtude des gîtes porphyriques, Initiative géoscientifique ciblée (IGC-4)
Résumé(disponible en anglais seulement)
The south coast of the island of Newfoundland is a diverse and potentially important district of granophile mineral deposits, in which several mineralized intrusive complexes span contrasting tectonostratigraphic zones of the Appalachian Orogen. In addition to molybdenum and tungsten deposits that represent potential producers, the district includes one of the world's largest producing fluorspar deposits, at St. Lawrence. The settings of mineral deposits vary, as do their associated commodities, but there is a common magmatic thread throughout the district. All major deposits are associated with evolved, alkali-calcic, siliceous granitoid rocks emplaced within a short time interval from ca. 388 Ma to ca. 375 Ma. Coherent U-Pb and Re-Os geochronology links these deposits to spatially associated plutons, even where direct physical connections are lacking. There are common geochemical themes that link prospective magmas, but these are not always easily visible through the geochemical and isotopic diversity connected to the contrasts in basement terranes along the belt. There is a dire need for other types of diagnostic data (e.g., Pb isotopes, accessory mineral chemistry) that can better unravel the respective contributions of magma sources, contaminants and fractionation histories to regional prospectivity.
There are contrasts in the erosional levels revealed in individual complexes, from endocontact disseminated mineralization in high-level granites, to sheeted vein complexes and related hydrothermal lodes associated with hidden subsurface plutons. The Grey River - Moly Brook area provides the best example of the latter setting, and has all of the expected characteristics of a large zoned hydrothermal system. This area is of particular interest in the context of exploring such blind systems, because high-resolution geophysical data provide potential 3D information to augment the direct data from drilling. Exploring for targets associated with hidden intrusions is never going to be easy, so examples such as this, for which multiple data sets exist, are obvious priorities for expanded research.