| Titre | Using magmatic biotite chemistry to differentiate barren and mineralized Silurian-Devonian granitoids of New Brunswick, Canada |
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| Auteur | Azadbakht, Z ;
Lentz, D R; McFarlane, C R M; Whalen, J B |
| Source | Contributions To Mineralogy and Petrology vol. 175, 69, 2020 p. 1-24, https://doi.org/10.1007/s00410-020-01703-2 |
| Année | 2020 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200115 |
| Éditeur | Springer |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1007/s00410-020-01703-2 |
| Media | papier; en ligne; numérique |
| Formats | pdf; html (Adobe® Reader®); xlsx (Microsoft® Excel®) |
| Province | Nouveau-Brunswick |
| SNRC | 21G; 21I/12; 21I/13; 21J; 21O; 21P/04; 21P/05; 21P/12; 21P/13 |
| Région | Bathurst; Fredericton; Saint John |
| Lat/Long OENS | -68.0000 -65.5000 48.0000 45.0000 |
| Sujets | potentiel minier; minéralisation; géologie du substratum rocheux; lithologie; roches ignées; roches intrusives; roches intrusives felsiques; granodiorites; granites; leucogranites; cadre tectonique;
magmatisme; intrusions; magmas; biotite; apatite; analyses géochimiques; analyses des éléments en trace; analyses des éléments majeurs; analyses par microsonde électronique; analyse par spectromètre de masse; analyses minéralogiques; cristallisation
fractionnée; cristallisation fractionnée; cristallisation; métallogénie; analyses pétrographiques; conditions de pression-température; géothermométrie; pétrogenèse; dynamique des fluides; Orogène Appalachien; Ceinture de Central Plutonic ; géologie
économique; géochimie; minéralogie; tectonique; Sciences et technologie; Nature et environnement; Phanérozoïque; Paléozoïque; Dévonien; Silurien |
| Illustrations | cartes de localisation; cartes géolscientiques généralisées; tableaux; photomicrographies; diagrammes ternaires; graphiques; diagrammes de phases |
| Programme | Initiative géoscientifique ciblée (IGC-5) Systèmes minéralisés intrusions/porphyriques - systèmes porphyriques liés aux arcs - temps et
espace |
| Diffusé | 2020 06 23 |
| Résumé | (disponible en anglais seulement)
The geochemistry of biotite crystals from thirty fertile and barren Silurian-Devonian granitoids of New Brunswick, Canada, was studied in situ using electron
microprobe and laser ablation inductively coupled plasma-mass spectrometry to investigate the suitability of biotite geochemistry as a diagnostic fertility index among these intrusions. The Fe2+/(Fe2+ + Mg2+) ratio of biotite varies as a function of
intrusion metal affinity, increasing from Cu-Mo-related (mean of 0.56 ± 0.12), to Mo-related (mean of 0.69 ± 0.06) to Sn-W-related (mean of 0.77 ± 0.16), with barren granitoids lying between Cu-Mo and Mo types (mean of 0.66 ± 0.06). The results show
a distinctive geochemical contrast between mineralized and barren samples. Compatible elements (Ti, Mg, Co, Ni, V, Cr, Ba, and Sr) decrease from barren to Cu-Mo, Mo, and Sn-W granitoids, whereas incompatible elements (Mn, Zn, Sn, W, Rb, Cs, and Li)
show the opposite trend. These two trends might indicate higher degree of fractionation indicated by biotite chemistry in Sn-W-related granites. Furthermore, barren intrusions have the lowest water content (1-3 wt.% H2O), whereas Sn-W and
Cu-Mo-related intrusions have between 3 and 6 wt.% H2O. Mo-bearing intrusions have a limited range of H2O contents (4-4.5 wt.%). A high degree of halogen enrichment related to degree of fractional crystallization results in enrichment of incompatible
elements in the magmas associated with Sn-W mineralization and is reflected by the geochemical characteristics of biotite from these systems. New metallogenic classifications are introduced using ternary V-Na-Li (ppm) and Sn + W (ppm) versus Ga (ppm)
to differentiate barren and mineralized granitic systems in New Brunswick. |
| GEOSCAN ID | 326452 |
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