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TitleGabbro intrusions along the Dog Bay Line - Appleton Fault Zone gold corridor, northeast-central Newfoundland: U-Pb baddeleyite geochronology and lithogeochemistry
AuthorHonsberger, I WORCID logo; Sandeman, H A I; Bleeker, WORCID logo; Kamo, S L
SourceNewfoundland and Labrador Department of Industry, Energy and Technology, Geological Survey, Current Research no. 23-1, 2023 p. 31-46
LinksOnline - En ligne
Alt SeriesNatural Resources Canada, Contribution Series 20220561
PublisherNewfoundland and Labrador Department of Industry, Energy and Technology
Mediapaper; digital; on-line
File formatpdf
ProvinceNewfoundland and Labrador
NTS1; 2; 11; 12
Lat/Long WENS -60.2500 -52.0000 51.5000 46.5000
Subjectsgeochronology; Science and Technology; metallic minerals; lithogeochemistry; gold; fault zones; uranium lead dating; baddeleyite; Appleton Fault Zone
Illustrationslocation maps; photographs; tables; diagrams; charts
ProgramTargeted Geoscience Initiative (TGI-6) Ore systems
Released2023 05 04
AbstractThe Dog Bay Line - Appleton Fault Zone gold corridor in the Exploits Subzone of northeast-central Newfoundland is prospective for orogenic gold mineralization but the history of deposition, magmatism, faulting, and tectonism is poorly understood. Gold-bearing, gabbroic hypabyssal intrusions (dykes and sills) within clastic sedimentary rocks between the Dog Bay Line and the Appleton Fault Zone provide insight into the timing and nature of processes that formed the host rocks along the structural corridor. This contribution presents a new Late Ordovician (Katian) high-precision U-Pb minimum baddeleyite age of 446.30 ± 0.44 Ma for an auriferous gabbro intrusion, the Midway Gabbro, from Labrador Gold Corporation's Kingsway gold project. This new Katian age provides a maximum age constraint on post-intrusion orogenic gold mineralization. The hypabyssal gabbro intrusions along the Dog Bay Line - Appleton Fault Zone gold corridor are grouped broadly into two lithogeochemical types. Type 1 gabbros are tholeiitic back-arc basin melts with minor light rare-earth and large-ion lithophile element enrichments and variably developed high field strength element troughs. Type 2 gabbros are transitional to calc-alkaline, arc-like magmas with modest to significant enrichment in light rare-earth elements and large-ion lithophile elements. Both Type 1 and Type 2 gabbros were emplaced in the Late Ordovician, whereas Silurian - Devonian gabbros are Type 2 only. Both Type 1 and Type 2 gabbros may have formed in the Tetagouche - Exploits back-arc basin. These findings indicate that emplacement of gabbro intrusions along the Dog Bay Line - Appleton Fault Zone gold corridor record a Late Ordovician to Devonian magmatic history from an intra-oceanic arc to an intracontinental deformation zone associated with orogenic gold mineralization. Imbrication of sedimentary-magmatic rock sequences along the Dog Bay Line - Appleton Fault Zone gold corridor is attributed to Devonian deformation during the Acadian orogenic cycle likely followed by Neo-Acadian (Late Devonian) and Carboniferous transpressive-transtensional along-strike displacement and dismemberment of the Acadian orogenic collage.
Summary(Plain Language Summary, not published)
This contribution presents a new age and geochemistry for gold-bearing rocks along fault zones in northeast-central Newfoundland. The results of this research increase understanding of the geological evolution of rocks containing gold ore; thus, will contribute to advancing targeted exploration models for gold deposits.

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