| Title | Geological and structural controls on hydrothermal alteration and W-Mo mineralization in the Sisson deposit, New Brunswick |
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| Author | Lang, J R; Duncan, R; Lentz, D; Zhang, W; Bustard, A; McFarlane, C R M; Thorne, K G |
| Source | Geological Association of Canada-Mineralogical Association of Canada, Joint Annual Meeting, Abstracts Volume vol. 37, 2014 p. 151-152  Open Access |
| Links | Online - En ligne (PDF 8.75 MB)
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| Year | 2014 |
| Publisher | Geological Association of Canada |
| Publisher | Mineralogical Association of Canada |
| Meeting | GAC-MAC Joint annual meeting; Fredericton, NB; CA; May 2014 |
| Document | serial |
| Lang. | English |
| Media | on-line; digital |
| 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/06; 21J/07 |
| Lat/Long WENS | -67.5000 -66.5000 46.5000 46.2500 |
| Subjects | igneous and metamorphic petrology; metallic minerals; hydrothermal alteration; intrusive rocks; igneous rocks; molybdenum; tungsten; mineralization; quartz diorites; shear zones; host rocks; scheelite;
molybdenite; wolframite; Sisson deposit; Ordovician; Cambrian |
| Program | Targeted Geoscience Initiative (TGI-4) Intrusion/Porphyry Ore Systems |
| Released | 2014 01 01 |
| 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 east-dipping metavolcanic and metasedimentary rocks of the Cambrian to Ordovician Tetagouche and Miramichi Groups on the east. Re-Os dates of ~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 ~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) quartzscheelite veinlets with biotite envelopes; (3) quartz-molybdenite±scheelite veinlets with sericite envelopes; (4) mostly late but possibly long-lived, larger and more continuous,
polymetallic quartz-shear 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, synhydrothermal 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. |
| GEOSCAN ID | 295885 |
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