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TitleConstraints on the evolution of the eastern margin of the Hearne craton: new data from the southwestern Rottenstone Domain, Trans-Hudson Orogen, Saskatchewan
AuthorMaxeiner, R O; Rayner, NORCID logo; Ansdell, K; Creaser, R
SourcePrecambrian Research vol. 381, 106851, 2022 p. 1-22,
Alt SeriesNatural Resources Canada, Contribution Series 20220345
Mediapaper; digital; on-line
File formatpdf
Lat/Long WENS-106.0000 -104.0000 56.0000 55.0000
Subjectsgeochronology; geochemistry; uranium lead dating; isotopes; samarium; neodymium; Hearne Craton; Trans-Hudson Orogen; Reindeer Zone
Illustrationslocation maps; photographs; tables; photomicrographs; Concordia diagrams; histograms; plots; element distribution diagrams; schematic models
ProgramGEM-GeoNorth: Geo-mapping for Energy and Minerals GEM Program Coordination
Released2022 10 24
AbstractThe Rottenstone Domain (RD) is a complex lithotectonic supracrustal belt of the Paleoproterozoic Trans-Hudson Orogen in Saskatchewan, Canada, located between the Archean Hearne craton and the juvenile Paleoproterozoic Reindeer Zone (RZ). Its evolution and crustal affinity have been under considerable debate in the past few decades, with most interpretations considering it to be part of RZ, but some hinting that certain elements might have affinities to the Archean hinterland. On the basis of bedrock mapping, U-Pb, Sm-Nd and lithogeochemical data, the rocks of the southwestern RD were subdivided into several lithodemic entities, which were used to reconstruct a plate tectonic framework for the western part of the Trans-Hudson Orogen during Orosirian time. A U-Pb zircon crystallization age of 2518 ± 6 Ma and depleted mantle model age (TDM) of 2.8 Ga for an augen granite confirmed that the western part of RD is part of the Hearne craton. A newly discovered structural inlier at the eastern boundary of RD consists of a central unit of 2045 ± 9 Ma augen granite, with TDM ages between 2.8 and 2.6 Ga, that was intruded into gneissic granite with a TDM of 3.3 Ga. The augen granite was interpreted as representing a rift-related granite, emplaced into Archean rocks of the Hearne craton. Two lithotectonic assemblages, one dominated by feldspathic quartzite and psammite the other by migmatitic psammite-psammopelite, are in structural contact with the granitic inliers and have model ages of 2.6-2.4 Ga. One of the feldspathic quartzite samples contains detrital zircon age modes at 1910 and 1860 Ma, and lesser Archean modes. Both assemblages were likely deposited in a forearc basin to the 1.865-1.850 Ga Wathaman continental arc. Recognition of Archean components and metasedimentary assemblages with older model ages than those in the RZ to the east, suggest that this southern part of RD is more closely affiliated with the Hearne craton. The eastern edge of RD coincides with a mylonite zone (Howard Lake shear zone), which likely represents a fundamental, although multiply reactivated, structural break separating Archean granitoids and structurally overlying metasedimentary rocks from rocks of the more juvenile Reindeer Zone.
Summary(Plain Language Summary, not published)
In this study, we present the results of regional bedrock mapping across the southern Rottenstone Domain in northern Saskatchewan. Metasedimentary rocks, which dominate this part of the Rottenstone Domain, were subdivided into a number of assemblages, in order to compare them to sedimentary successions delineated elsewhere. Two areas of enigmatic granitic gneisses were also investigated. New lithogeochemical, and isotopic data from these rocks are used to correlate these newly described assemblages and crustal blocks with previously defined entities, and to argue that the geological elements of the southern Rottenstone Domain are more closely affiliated with those of the Hearne craton than those of the Reindeer Zone. The new data also contribute to a reconstruction of a plate tectonic framework.

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