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TitleThe evolution of Keele Arch, a multiphase feature of the northern mainland, Northwest Territories
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorMacLean, B C; Fallas, K MORCID logo; Hadlari, TORCID logo
SourceGeological Survey of Canada, Bulletin 606, 2015, 47 pages, Open Access logo Open Access
PublisherNatural Resources Canada
Mediaon-line; digital
File formatpdf
ProvinceNorthwest Territories; Yukon
NTS95N; 95O; 96B; 96C; 96D; 96E; 96F; 96G; 96J; 96K; 96L; 96M; 96N; 96O; 97B; 97C; 106F; 106G; 106H; 106I; 106J; 106K; 106L; 106N; 106O; 106P; 107A
AreaColville Hills; Franklin Mountains; Mackenzie Valley; Great Bear Plain; Peel Plateau; Peel Plain; Horton Plain; Anderson Plain
Lat/Long WENS-134.0000 -122.0000 70.0000 63.0000
Subjectsstructural geology; stratigraphy; geophysics; structural features; faults; folds; stratigraphic analyses; tectonic setting; erosion; depositional environment; depositional history; fold axes; Keele Arch; Paleozoic; Cambrian; Silurian; Ordovician; Mesozoic; Jurassic; Cretaceous
Illustrationslocation maps; stratigraphic columns
ProgramGEM: Geo-mapping for Energy and Minerals Mackenzie Delta and Corridor
Released2016 01 28
AbstractKeele Arch is a zone of structural, erosional, and depositional features along a corridor between the eastern Colville hills and the Franklin Mountains, Northwest Territories. It has a long history of basin-to-arch reversals.
Paleomaps and sections illustrate the arch's evolution through six phases: 1) uplift as a very early Cambrian pre-rift high, 2) subsidence into a graben chain during Cambrian to mid-Ordovician time, 3) uplift of its southern half into a pre-Devonian arch extending southward from the present day northern Franklin Mountains to beyond Johnson River, 4) renewed uplift into a pre-Cretaceous arch running from north of Lac des Bois to Johnson River, 5) mid-Cretaceous reactivation of the pre-Cretaceous and southern pre-Devonian arches, 6) subsidence of its central zone into Brackett Basin and inversion of the Cambrian McConnell graben into the McConnell Range during late-Campanian to Paleocene time.
Keele Arch consists of four parts: 1) a northern segment extending northeastward from the Northern Franklin Mountains toward Lac des Bois; 2) the north half of Keele Tectonic Zone under the northern Franklin Mountains; 3) between Brackett Lake and Keele River; 4) a fourth and poorly understood segment under Mackenzie Valley, south of Keele River, where the arch axes appear to fall into two sets: an eastern set of Cambrian to mid-Ordovician sag axes and latest Silurian to Eocene uplifts, and a western set of Cambrian to mid-Cretaceous arch axes that tracks across a block of Proterozoic rock directly overlain by Devonian strata.
The arch's economic significance is not fully understood.
Summary(Plain Language Summary, not published)
Keele anomaly is today an arch extending from north of Lac des Bois to near Johnson R in the NWT but has undergone both subsidence and uplift. Paleo-geology maps and sections show six development phases: 1) uplift - very early Cambrian bulge. 2) subsidence - graben chain in Cambrian to mid-Ordovician time. 3) uplift - Keele Tectonic Zone (KTZ) and an area to its south in the Late Silurian. 4) renewed uplift - pre-Cretaceous arch. 5) reactivation of the pre-Cret, and part of the pre-Dev, arch during the mid-Cret. 6) subsidence - Brackett Basin in late-Campanian to Paleocene and Eocene inversion of McConnell Graben into McConnell Range. The anomaly has four parts: 1) Northern Franklin Mtns to Lac des Bois. 2) The north half of KTZ (northern Franklin Mtns). 3) The south half of KTZ (Brackett L. to Keele R). 4) Under Mackenzie Valley, south of Keele R. Axes in two sets: eastern set of Camb. to mid-Ord. sags and latest Sil. to Eocene uplifts; western set of Camb. to mid-Cret. arches.

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