| Title | Geological and structural controls on hydrothermal alteration and W-Mo mineralization in the Sisson deposit, New Brunswick |
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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Lang, J R; Duncan, R; Lentz, D R; Zhang, W; Bustard, A; McFarlane, C R M; Thorne, K G |
| 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. 327-341, https://doi.org/10.4095/296474  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 Geological and structural
controls on hydrothermal alteration and W-Mo mineralization in the Sisson deposit, New Brunswick |
| File format | pdf |
| Province | New Brunswick |
| NTS | 21J/02; 21J/03; 21J/06; 21J/07 |
| Area | Mount Pleasant; Sisson |
| Lat/Long WENS | -67.1667 -66.8333 46.5000 46.1667 |
| Subjects | economic geology; porphyry deposits; porphyry copper; mineral exploration; glacial deposits; mineralization; tungsten; molybdenum; tin; bismuth; copper; gold; structural features; hydrothermal
alteration; hydrothermal deposits; Sisson deposit; Mount Pleasant deposit; Paleozoic; Devonian; Silurian; Ordovician |
| Illustrations | location maps; stereonets; photographs; cross-sections; block diagrams; photomicrographs |
| Program | Targeted Geoscience Initiative (TGI-4) Intrusion/Porphyry Ore Systems |
| Released | 2015 06 11; 2023 03 17 |
| Abstract | The Sisson deposit is a Late Devonian, structurally-controlled, intrusion-related W-Mo deposit located in west-central New Brunswick. Resources are estimated at 383 Mt grading 0.067 % WO3 and 0.021 % Mo
(measured/indicated) and 178 Mt grading 0.051 % WO3 and 0.021 % Mo (inferred). Host rocks to Sisson include quartz diorite and gabbro phases (432 Ma; U-Pb on titanite) of the Howard Peak intrusion on the west, which are in fault contact across the
vertical, north-trending Sisson shear zone with north-northwest-striking, steeply eastdipping metavolcanic and metasedimentary rocks of the Cambrian to Ordovician Tetagouche and Miramichi Groups on the east. Re-Os dates of ca. 378 Ma on molybdenite
overlap U-Pb dates on zircon from narrow granite dykes within the deposit, which are likely related to the Late Devonian Nashwaak Granite batholith located immediately northwest of the deposit. The deposit is cut by narrow, undeformed, barren granite
porphyry dykes dated at ca. 364 Ma (U-Pb on zircon).
The Sisson deposit obliquely straddles the Sisson shear zone. Hydrothermal activity comprises: (1) early, weakly to unmineralized amphibole veinlets with albite alteration envelopes and small,
erratically-distributed zones of biotite± pyrite alteration; (2) quartz- scheelite veinlets with biotite envelopes; (3) quartz-molybdenite±scheelite veinlets with sericite envelopes; (4) mostly late but possibly long-lived, larger and more
continuous, polymetallic quartzshear veins with broad sericite envelopes and associated sulphide-rich veinlets, which also introduced minor Cu, Bi, Sb, As, Pb and Zn to the deposit; and (5) rare endoskarn with scheelite mineralization of uncertain
timing in narrow granite dykes intersected only at depths of >400 metres. Alteration is mostly restricted to the envelopes which enclose veinlets. Scheelite mineralization occurs primarily in quartz veinlets and their alteration envelopes,
molybdenite is restricted to quartz veinlets, and minor ferberitic wolframite, mostly replaced by scheelite, occurs in some quartz-scheelite veinlets and in most quartz-shear veins.
Veins throughout the deposit form a sheeted array with consistent
northwest strike and steep to moderate southwest dips. The nature and geometry of the vein sets are most compatible with formation during crustal extension, which was synchronous with sinistral, syn-hydrothermal displacement across the north-trending
Sisson shear zone. The structural plumbing system focused ascent of W-mineralizing fluids from intrusions at depth, the presence of which is indicated by syn-hydrothermal granite dykes within the deposit. Precipitation of W and Mo mineralization
resulted from chemical interactions between hydrothermal fluids and wall rock at a low fluid to rock ratio, and from changes in sulphur and oxygen fugacity. |
| 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 | 296474 |
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