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TitleU-Pb detrital zircon geochronological constraints on Siderian and Orosirian rocks of Boothia Peninsula and Somerset Island (Nunavut, Canada)
AuthorRegis, D; Sanborn-Barrie, MORCID logo
SourcePrecambrian Research vol. 387, 106991, 2023 p. 1-22,
Alt SeriesNatural Resources Canada, Contribution Series 20220093
Mediapaper; digital; on-line
File formatpdf
NTS57C; 57D; 57E; 57F; 57G; 57H; 58A; 58B; 58C; 58D; 58E; 58F; 67D; 67E; 67H; 68A; 68D; 68E
AreaBoothia Peninsula; Somerset Island
Lat/Long WENS -99.0000 -90.0000 74.2500 69.5000
SubjectsScience and Technology; general geology; mineralogy; zircon; uranium lead dating; Boothia-Somerset; Canadian Shield
Illustrationslocation maps; photographs; graphs; charts; cross-plots; diagrams
ProgramGEM2: Geo-mapping for Energy and Minerals Rae Province, Boothia-Somerset
Released2023 02 19
AbstractBoothia Peninsula-Somerset Island is an under-explored frontier region of Arctic Canada, long considered part of the Rae craton, that exposes widespread semipelitic rocks with minor quartzite, marble, and calc-silicate, and late Neoarchean-Paleoproterozoic plutonic rocks. Detrital zircon U-Pb SHRIMP analyses constrain the timing of deposition and provenance of three sequences. An older clastic succession (sequence 1), deposited after ca. 2500 Ma, is characterized by major modes at 2560-2510 Ma, consistent with unroofing of Boothia basement rocks and local derivation of detrital grains. Minimal detritus representative of Rae craton (i.e., 2970 Ma, 2790-2600 Ma) suggests the basin formed either at a thin margin of the western Rae craton or as part of a distinct terrane (Boothia-Somerset) separate from the western Rae craton at ca. 2500 Ma. An extensional setting during deposition of sequence 1 may relate to slab retreat. Texturally and chemically mature quartzite (sequence 2) was deposited between 2280 and 2020 Ma in a shallow or beach-like environment indicative of a passive-margin setting. Younger clastic rocks (sequence 3) associated with, and thought to overlie, carbonate strata are characterized by a significant population of 2020-1970 Ma detrital grains, consistent with exhumation of the Thelon magmatic arc and deposition of its detritus between 1960 and 1940 Ma. Overall, this detrital dataset highlights a polycyclic ca. 600 million year evolutionary history on, or outboard of, a thinned Rae cratonic margin. These results strengthen the possible linkages to the central and northern Canadian Shield and open up the potential for a distinct ribbon terrane, which may have connections to the China and Yangtze cratons.
Summary(Plain Language Summary, not published)
This manuscript presents new SHRIMP (Sensitive High-Resolution Ion Microprobe) zircon U-SPb geochronological results for nine sedimentary rocks and two plutonic samples in the Boothia Peninsula - Somerset Island area (Nunavut). Detailed mapping and sampling for U-Pb geochronology (two field seasons: 2017 and 2018) was carried out as part of Natural Resources Canada's Geomapping for Energy and Minerals (GEM2) Boothia-Somerset project. Samples have been collected and analyzed to place time constraints on the deposition of the different sedimentary packages and better constrain the geologic evolution of the area.

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