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TitleGeological and structural controls on hydrothermal alteration and W-Mo mineralization in the Sisson deposit, New Brunswick
DownloadDownload (whole publication)
AuthorLang, J R; Duncan, R; Lentz, D R; Zhang, W; Bustard, A; McFarlane, C R M; Thorne, K G
SourceTGI 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, (Open Access)
LinksCanadian Database of Geochemical Surveys, downloadable files
LinksBanque de données de levés géochimiques du Canada, fichiers téléchargeables
PublisherNatural Resources Canada
Documentopen file
Mediaon-line; digital
RelatedThis publication is contained in Rogers, N; (2015). TGI 4 - Intrusion Related Mineralisation Project: new vectors to buried porphyry-style mineralisation, Geological Survey of Canada, Open File 7843
RelatedThis publication is related to Lang, J R; Duncan, R; Lentz, D; Zhang, W; Bustard, A; McFarlane, C R M; Thorne, K G; (2014). Geological and structural controls on hydrothermal alteration and W-Mo mineralization in the Sisson deposit, New Brunswick, Geological Association of Canada-Mineralogical Association of Canada, Joint Annual Meeting, Abstracts Volume vol. 37
File formatpdf
ProvinceNew Brunswick
NTS21J/02; 21J/03; 21J/06; 21J/07
AreaMount Pleasant; Sisson
Lat/Long WENS -67.1667 -66.8333 46.5000 46.1667
Subjectseconomic 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
Illustrationslocation maps; stereonets; photographs; cross-sections; block diagrams; photomicrographs
ProgramTargeted Geoscience Initiative (TGI-4), Intrusion/Porphyry Ore Systems
Released2015 06 11
AbstractThe 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.