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TitleLatest Silurian syntectonic sedimentation and magmatism and Early Devonian orogenic gold mineralization, central Newfoundland Appalachians, Canada: setting, structure, lithogeochemistry, and high-precision U-Pb geochronology
AuthorHonsberger, I WORCID logo; Bleeker, WORCID logo; Kamo, S L; Sandeman, H A I; Evans, D T W; Rogers, N; van Staal, C RORCID logo; Dunning, G R
SourceGeological Society of America Bulletin 2022 p. 1-25, Open Access logo Open Access
Alt SeriesNatural Resources Canada, Contribution Series 20210306
PublisherGeological Society of America
Mediapaper; on-line; digital
RelatedNRCan photo(s) in this publication
File formatpdf
ProvinceNewfoundland and Labrador
NTS1M/13; 2D/04; 2D/05; 2D/12; 2D/13; 11P/13; 11P/14; 11P/15; 11P/16; 12A/01; 12A/02; 12A/03; 12A/04; 12A/05; 12A/06; 12A/07; 12A/08; 12A/09; 12A/10; 12A/11; 12A/15; 12A/16
AreaIsland of Newfoundland; Red Indian Lake; Victoria Lake; Sandy Lake; Meelpaeg Reservoir
Lat/Long WENS -58.0000 -55.5000 48.8833 47.9167
Subjectseconomic geology; tectonics; structural geology; geochronology; geochemistry; Science and Technology; Nature and Environment; Lower Devonian; Upper Silurian; tectonic evolution; tectonic setting; magmatism; intrusions; orogenies; downgoing slab; crustal uplift; erosion; hydrothermal systems; fluid flow; thermal history; depositional history; sedimentation; mineral exploration; mineral potential; mineral deposits; gold; mineralization; ore mineral genesis; ore controls; structural controls; lithogeochemistry; radiometric dating; uranium lead dating; structural analyses; structural trends; bedrock geology; basement geology; structural features; fault zones; faults; splays; shear zones; lithology; granitic rocks; sedimentary rocks; conglomerates; igneous rocks; intrusive rocks; monzonites; monzo-granites; granodiorites; porphyries; volcanic rocks; felsic volcanic rocks; quartz veins; emplacement; mass spectrometer analysis; mineral occurrences; crustal structure; Appalachian Province; Dunnage Zone; Acadian Orogeny; Salinic Orogeny; Valentine Lake Shear Zone; Gander Zone; Wilding Lake Pluton; Wilding Lake Prospect; Valentine Lake Deposit; Rogerson Lake Conglomerate; Botwood Basin; Phanerozoic; Paleozoic; Devonian; Silurian; Precambrian; Proterozoic
Illustrationsgeoscientific sketch maps; photographs; photomicrographs; cross-sections; equal-area stereonet projections; tables; Concordia diagrams; plots; block diagrams; schematic models
ProgramTargeted Geoscience Initiative (TGI-6) Ore systems
Released2022 03 03
AbstractThe eastern Dunnage Zone of the central Newfoundland Appalachians hosts Paleozoic orogenic gold mineralization along a northeast-trending, crustal-scale fault corridor that extends for more than 200 km. This orogenic gold system is characterized by polyphase, structurally controlled, quartz vein systems that cut Neoproterozoic granitoid rocks and unconformably overlying syntectonic, polymict conglomerate and associated transitional to calc-alkaline bimodal igneous rocks.
High-precision chemical abrasion-isotope dilution-thermal ionization mass spectrometry (CA-ID-TIMS) U-Pb geochronology confirms a widespread, latest Silurian magmatic pulse (422-420 Ma) that is attributed to a transient phase of lithospheric extension resulting from asthenospheric and crustal melting related to slab break-off. Syntectonic conglomerate was deposited as a basal unit during extension-related uplift and erosion that lasted until ca. 418 Ma in north-central Newfoundland. Orogenic gold mineralization associated with syntectonic sedimentation and magmatism is hosted within third-order shear vein systems that form offshoots within a triangle zone-like structural corridor between southeast- and northwest-dipping, second-order fault splays and shear zones. The southeast-dipping fault system formed during northwest migration of the Acadian thrust front, whereas the northwest-dipping faults and shear zones are Salinic structures that were reactivated in the Early Devonian.
Primary hydrothermal rutile in the orogenic gold-mineralized quartz veins produced ages of ca. 410 Ma. These ages are consistent with quartz vein emplacement and orogenic gold mineralization as a result of hydrothermal fluid-pressure cycling related to far-field compression and thermal perturbations during the Early Devonian Acadian orogenic cycle. The setting and process evolution of the central Newfoundland gold district are remarkably similar to that of world-class orogenic gold systems of the Canadian Shield.
Summary(Plain Language Summary, not published)
This research documents the setting of orogenic gold mineralization along highly prospective fault zones in central Newfoundland and constrains the timing of key syntectonic processes associated with mineralization. Data are consistent with a tectonic model involving latest Silurian lithospheric extensional faulting followed by Early Devonian thrust re-imbrication and gold mineralization. Results of this research imply that gold exploration in central Newfoundland should target a structural triangle zone between crustal-scale faults of opposing dip.

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