|Titre||Geology and tectonic history of the Bathurst Supergroup, Bathurst Mining Camp and its relationships to coeval rocks in southwestern New Brunswick and adjacent Maine - a synthesis|
|Auteur||van Staal, C R; Wilson, R A; Rogers, N; Fyffe, L R; Langton, J P; McCutcheon, S R; McNicoll, V; Ravenhurst, C E|
|Source||Massive sulfide deposits of the Bathurst Mining Camp, New Brunswick, and northern Maine; par Goodfellow, W D (éd.); McCutcheon, S R (éd.); Peter, J M (éd.); Economic Geology Monograph vol. 11, 2003 p.
|Liens||Online - En ligne |
|Séries alt.||Commission géologique du Canada, Contributions aux publications extérieures 2000115|
|Éditeur||Society of Economic Geologists |a Littleton, CO (Littleton, CO)|
|Document||publication en série|
|Media||papier; en ligne; numérique|
|Formats||doc; xls; pdf|
|SNRC||21G; 21H; 21I; 21J; 21O; 21P|
|Lat/Long OENS|| -68.0000 -64.0000 48.0000 45.0000|
|Sujets||schistes; grès; schistes; décrochement horizontal; croûte continentale; gîtes sulfureux; datations radiométriques; pyroclastiques; tufs volcaniques; roches volcaniques; minéralisation; roches volcaniques
mafiques; géochimie; géochronologie; pétrologie ignée et métamorphique; sédimentologie; minéralogie|
|Illustrations||geological sketch maps; stratigraphic columns; graphs; schematic diagrams; cross-sections, structural|
|Programme||Camp minier de Bathurst, Mesures Canada-Nouveau-Brunswick relatives au Programme de la science et de la technologie de l'exploration (EXTECH II), 1994-1999|
|Résumé||(disponible en anglais seulement)|
The Bathurst Mining Camp is made up of several different tectonic blocks and slivers -- the Fournier, California Lake, Tetagouche, and Sheephouse Brook blocks
and the blueschist and Bamford Brook slivers. These blocks and slivers are characterized by unique Arenig-Caradoc volcanic stratigraphies, indicating they represent widely separated, ensialic to ensimatic portions of the Tetagouche-Exploits back-arc
basin. Their structural juxtaposition took place during the Ashgill-Ludlow closure of the Tetagouche-Exploits back-arc basin.
The Tetagouche-Exploits back-arc basin formed in response to rifting of the northwest-facing Popelogan arc, although the
extension-rifting history was diachronous and involved multiple stages. The rifting responsible for the California Lake block (ca. 472-468 Ma) took place before the rifting of the Tetagouche (ca. 467-465 Ma) and Sheephouse Brook blocks (ca. 466-464
Ma). These three blocks have ensialic to transitional crust and share a similar pre-Arenig basement consisting of Miramichi Group deep-water sandstones and shales. Oceanic to transitional back-arc crust is preserved in the Fournier block and the
blueschist and Bamford Brook slivers. The various blocks and slivers were sequentially incorporated into the Brunswick subduction complex during closure of the back-arc basin.
Massive sulfide deposits in the Brunswick mining camp mainly occur in
the California Lake, Tetagouche, and Sheephouse Brook blocks. Radiometric age dating indicates that massive sulfide deposition took place during a protracted period of ca. 12 m.y., although occurring at different intervals in each block. High heat
flow due to extension and/or rifting of the Popelogan arc combined with anoxic bottom conditions in the associated basins seem to be a prerequisite for formation of the large massive sulfide deposits. The oldest known massive sulfides are hosted by
early Arenig (ca. 478 Ma) dacites of the Clearwater Stream Formation of the Sheephouse Brook Group, which may represent the earliest stages of extension of the Popelogan arc. The main massive sulfide bodies in the California Lake Group are
represented by the middle to upper Arenig (ca. 472-470 Ma) Caribou-type deposits, whose formation coincides with the early stages of rifting of the California Lake block from the Popelogan arc. The large, massive sulfide deposits in the Tetagouche
Group (referred to as the Brunswick-type deposits) are typically hosted by, or intimately associated with, the pyroclastic and tuffaceous sedimentary rocks that occur near or at the top of the Nepisiguit Falls Formation (ca. 469-468 Ma). The
Brunswick-type deposits formed during extension rather than rifting of the Tetagouche block from the Popelogan arc, because mafic volcanism does not accompany felsic volcanism in the Nepisiguit Falls Formation. Rifting-related mafic volcanism becomes
abundant in the overlying Flat Landing Brook Formation (ca. 467-465 Ma), the rhyolites of which host a few small massive sulfide deposits. Some contemporaneous massive sulfide mineralization occurs also in the coeval feldspar-porphyritic rhyolites of
the Sheephouse Brook Group.