| Titre | Magmatic evolution in Devonian granitic rocks and relation to granophile mineralization in New Brunswick: application of biotite trace element mapping with EPMA and LA-ICP-MS |
| Télécharger | Téléchargements |
| |
| Licence | Veuillez noter que la Licence du gouvernement
ouvert - Canada remplace toutes les licences antérieures. |
| Auteur | Azadbakht, Z ;
Lentz, D R; McFarlane, C R M |
| Source | TGI 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. 507-519, https://doi.org/10.4095/296486  Accès ouvert |
| Liens | Canadian Database of Geochemical Surveys, downloadable files
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| Liens | Banque de données de levés géochimiques du Canada,
fichiers téléchargeables
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| Image |  |
| Année | 2015 |
| Éditeur | Ressources naturelles Canada |
| Document | dossier public |
| Lang. | anglais |
| DOI | https://doi.org/10.4095/296486 |
| Media | en ligne; numérique |
| Référence reliée | Cette publication est contenue dans TGI 4 -
Intrusion Related Mineralisation Project: new vectors to buried porphyry-style mineralisation |
| Référence reliée | Cette publication est reliée à les
publications suivantes |
| Formats | pdf |
| Province | Nouveau-Brunswick |
| SNRC | 21G |
| Région | Lake George |
| Lat/Long OENS | -68.0000 -66.5000 46.0000 45.0000 |
| Sujets | gisements porphyriques; cuivre porphyrique; prospection minière; minéralisation; biotite; granodiorites; gisements minéraux hydrothermaux; altération hydrothermale; tungstène; molybdène; or; antimoine;
roches magmatiques; milieux tectoniques; cadre tectonique; évolution tectonique; gîtes granophyriques; analyse par spectromètre de masse; gîtes magmatiques; magmatisme; Dépôt de Mount Pleasant ; géologie économique; tectonique; minéralogie;
Paléozoïque; Dévonien |
| Illustrations | cartes de localisation; graphiques; photomicrographies |
| Programme | Initiative géoscientifique ciblée (IGC-4) Étude des gîtes porphyriques |
| Diffusé | 2015 06 11; 2023 03 17 |
| Résumé | (disponible en anglais seulement)
Two suites of felsic intrusions were emplaced during the later parts of the Appalachian orogenic cycle in New Brunswick. However, just those associated with
crustal thickening processes of Acadian orogeny, post Acadian uplift, and Neoacadian orogeny are mineralized with granophile elements to form Sn, W, Mo, Cu, Bi, Sb, and Au deposits, as well as Ta, Li, base-metals, and U mineralization. Biotite major
element classification indicated that these intrusions are mostly A- and S-type granitoids and their hybrid varieties; some I-type granitoids are also present in the area.
Magmatic biotite from forty-two of these Devonian intrusions was studied by
electron microprobe (EPMA) and LA -ICP-MS at the University of New Brunswick. Whereas major elements are typically constant from core to rim, biotite grains can show remarkable trace element zoning. LA-ICP-MS trace element maps were also produced
when permitted by the size of the biotite, frequency of the mineral inclusions, degree of alteration, and the laser spot size required to achieve sub-ppm detection limits. In this study, unaltered biotite grains with minor mineral inclusions, and
diameters larger than 300 ?m, display trace-element zoning patterns. Furthermore, smaller biotite tends to be more susceptible to intracrystalline diffusion. As a result, their elemental zoning should be further studied and cross -checked with other
characteristics.
Results of this study showed LILE zoning, including Cs, Ba, and Rb, for most of the biotite grains. As these elements are highly incompatible, any zoning can be a result of the magma evolution history recorded within the biotite
crystalline structure. Any other trace element pattern following them will also be of an igneous source. For example, biotite grains from the Pleasant Ridge granite show an increase from core to rim for Cs and Sn and a decrease for W and Sc. Copper
is also high along the cleavages where biotite is weakly altered to chlorite. These observations coupled with an increase in F/Cl content from 770 to 1300 indicate that fractional crystallisation of this granite led to Sn mineralization. Tin is
positively correlated with Fe/(Fe+Mg), but negatively correlated with FeT/ Ti; this relationship may indicate that the Sn content of biotite increases with low fo2 and low temperatures as indicated by the iron/magnesium ratio.
According to the
results, the use of biotite as an indicator of trace element changes within granitic systems was achieved; with the help of other types of data, the composition of biotite may be a useful tool to indicate a difference between barren and mineralized
granophile-element rich systems. |
| Sommaire | (Résumé en langage clair et simple, non publié)
L'Initiative géoscientifique ciblée (IGC-4) est un programme géoscientifique fédéral de collaboration qui fournit à l'industrie les
connaissances géoscientifiques et les techniques novatrices de prochaine génération dont elle a besoin pour mieux détecter les gîtes minéraux enfouis, réduisant ainsi certains risques liés à l'exploration. Ce volume résume les activités de recherche
effectuées dans le cadre du projet de minéralisation lié à des intrusions de l'Initiative géoscientifique ciblée 4 qui était axé sur des systèmes minéralisés porphyriques associés aux dépôts de Cu et de Cu-Mo dans le centre-sud de la
Colombie-Britannique et aux dépôts de Sn-W-Mo-In au Nouveau-Brunswick, en Nouvelle-Écosse et à Terre-Neuve-et-Labrador. |
| GEOSCAN ID | 296486 |
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