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TitreThe south Newfoundland granophile mineral district: features and opportunities for research on blind deposits
TéléchargerTéléchargement (publication entière)
AuteurKerr, A
SourceTGI 4 - Intrusion Related Mineralisation Project: new vectors to buried porphyry-style mineralisation; par Rogers, N (éd.); Commission géologique du Canada, Dossier public 7843, 2015 p. 383-401, (Accès ouvert)
LiensCanadian Database of Geochemical Surveys, downloadable files
LiensBanque de données de levés géochimiques du Canada, fichiers téléchargeables
ÉditeurRessources naturelles Canada
Documentdossier public
Mediaen ligne; numérique
Référence reliéeCette publication est contenue dans Rogers, N; (2015). TGI 4 - Intrusion Related Mineralisation Project: new vectors to buried porphyry-style mineralisation, Commission géologique du Canada, Dossier public 7843
Lat/Long OENS -56.5000 -55.0000 48.0000 47.5000
Sujetsgisements porphyriques; cuivre porphyrique; prospection minière; minéralisation; altération; tungstène; molybdène; étain; bismuth; gisements minéraux; roches granitiques; gîtes magmatiques; gîtes granophyriques; spath fluor; datations au uranium-plomb; datations radiométriques; altération hydrothermale; Formation de Tickle Point ; Groupe de Connaigre Bay ; Granite d'Harbour Breton ; Groupe de Long Harbour ; Formation de Cinq Isles ; géologie économique; géochronologie; minéraux métalliques; Paléozoïque; Dévonien
Illustrationslocation maps; photographs; plots; histograms; Concordia diagrams
ProgrammeInitiative géoscientifique ciblée (IGC-4), Étude des gîtes porphyriques
Diffusé2015 06 11
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.