| Title | Biotite chemistry as a monitor of magma fertility and mineralisation potential: results from the Devonian granitoids of New Brunswick |
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| |
| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Azadbakht, Z ;
Lentz, D R; McFarlane, C R M; Rogers, N |
| Source | TGI 4 - Intrusion Related Mineralisation Project: new vectors to buried porphyry-style mineralisation; by Rogers, N (ed.); Geological Survey of Canada, Open File 7843, 2015 p. 563-564, https://doi.org/10.4095/296492  Open Access |
| Links | Canadian Database of Geochemical Surveys, downloadable
files
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| Links | Banque de données de levés géochimiques du Canada,
fichiers téléchargeables
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| Image |  |
| Year | 2015 |
| Publisher | Natural Resources Canada |
| Document | open file |
| Lang. | English |
| Media | on-line; digital |
| Related | This publication is contained in TGI 4 - Intrusion Related
Mineralisation Project: new vectors to buried porphyry-style mineralisation |
| Related | This publication is related to the following
publications |
| File format | pdf |
| Province | New Brunswick |
| NTS | 21G; 21H; 21I; 21J; 21O; 21P |
| Lat/Long WENS | -68.0000 -64.0000 48.0000 45.0000 |
| Subjects | economic geology; igneous and metamorphic petrology; geochemistry; porphyry deposits; porphyry copper; mineral exploration; mineralization; biotite; tungsten; tin; molybdenum; gold; antimony; magmatic
rocks; intrusive rocks; igneous rocks; vein deposits; magmatism; magma differentiation; magmatic deposits; Lake George deposit; Paleozoic; Devonian |
| Illustrations | location maps; plots; photomicrographs |
| Program | Targeted Geoscience Initiative (TGI-4) Intrusion/Porphyry Ore Systems |
| Released | 2015 06 11; 2023 03 17 |
| Abstract | There are over 150 granitoid intrusions in the New Brunswick; however, all the mineralised intrusions formed in relation to Acadian and Neoacadian orogenic phases of Appalachian accretion. These
granitoids range in age from 423 to 360 Ma, and include examples of pre-, syn-, late-, and post-tectonic emplacement with affinities ranging from primitive to highly evolved A-, S-, and I-types granitoids along with their hybrid varieties. Many of
these are spatially and temporally related to specific styles of mineralization, producing deposits of Sn, Ta, Li, Sb, W, Mo, Cu, and Au, as well as other base-metals and U.
Igneous biotite crystallises over a wide range of conditions and reacts
very sensitively to physio-chemical conditions like halogen and oxygen fugacities, pressure, temperature and chemical composition of the magmas. This sensitivity makes biotite a suitable mineral for identifying the petrogenetic processes,
mineralization and alteration of the host granitic rocks. The following features make biotite a valuable probe of magma composition: i) It is the most important reservoir of any excess aluminium in granites that do not contain modal garnet,
cordierite, or the Al2SiO5 polymorphs; therefore, it directly reflects the peraluminosity of the host magma in such rocks; ii) it is the most readily available indicator of oxidation state; and iii) it can provide information about the F and Cl
composition of the magma.
Previous studies have shown that biotite, and to lesser extent hornblende and magnetite, continuously equilibrates with host liquids. Consequently, a core-to-rim study of these minerals and their compositional zoning can
provide a record of magma evolution so that the origin and evolution of granitoids can be documented. The aim of this study is to calculate fluoride and chloride activity of aqueous fluids based on measuring F and Cl contents in the minerals
containing hydroxyl and halogens, using a combination of electron microprobe and Laser Ablation ICP-MS. These data will be combined and compared with whole-rock trace element geochemistry. The results are expected to help constrain crystallisation
conditions, volatile exsolution, and fluorine-chlorine activity of fluids associated with these intrusions, and also to examine the degree of subsolidus re-equilibration using various geothermobarometry techniques. By linking these results to the
various styles/types of granitoids and their associated mineralisation it is hoped to establish biotite composition as a robust indicator of an intrusions ore potential. |
| Summary | (Plain Language Summary, not published)
The Targeted Geoscience Initiative (TGI-4) is a collaborative federal geoscience program that provides industry with the next generation of geoscience
knowledge and innovative techniques to better detect buried mineral deposits, thereby reducing some of the risks of exploration. This volume summarises research activities completed under the TGI 4 Intrusion Related Mineralisation Project that
focused on porphyry-style ore systems related to the Cu- and Cu-Mo deposits of South-Central British Columbia and the Sn-W-Mo-In deposits in New Brunswick, Nova Scotia and Newfoundland. |
| GEOSCAN ID | 296492 |
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