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TitleInsights into the tectonothermal history of Melville Peninsula, Nunavut, provided by in situ SHRIMP geochronology and thermobarometry
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AuthorBerman, R G; Davis, W J; Corrigan, D; Nadeau, L
SourceGeological Survey of Canada, Current Research (Online) 2015-4, 2015, 22 pages, https://doi.org/10.4095/295852
Year2015
PublisherNatural Resources Canada
Documentserial
Lang.English
Mediaon-line; digital
File formatpdf
ProvinceNunavut
NTS46I; 46J; 46K; 46L; 46M; 46N; 46O; 46P; 47A; 47B; 47C; 47D
AreaMelville Island
Lat/Long WENS-88.0000 -80.0000 70.0000 66.0000
Subjectsgeochronology; structural geology; tectonics; thermobarometry; metamorphic rocks; garnet; deformation; foliation; metamorphism; metamorphic facies; granulite facies; structural features; Archean; SHRIMP; Precambrian; Proterozoic
ProgramRae Province, Chantrey-Thelon, GEM2: Geo-mapping for Energy and Minerals
Released2015 06 05
AbstractThermobarometric and in situ SHRIMP monazite geochronology indicate that two distinct metamorphic and deformational events affected Melville Peninsula. Monazite inclusions in garnet from two samples yielded ages of 2546 ± 7 Ma and 2539 ± 8 Ma. Textural features suggest they date an early deformation event in the development the Arrowsmith Orogen. Four samples from southern Melville Peninsula record monazite growth between ca. 1860 Ma and ca. 1820 Ma. Textures suggest that 1863 ± 6 Ma metamorphism initiated prior to pervasive regional deformation. Monazite growth is interpreted to date syntectonic garnet growth at ca. 1840 Ma and syntectonic, peak metamorphism at 1829 ± 4 Ma to 1825 ± 4 Ma. Petrological calculations define a clockwise P-T-t path consistent with crustal thickening that is attributed to ca. 1870 Ma collision of the Rae Craton with Meta Incognita microcontinent. Samples on northern Melville Peninsula record younger (ca. 1815-1767 Ma) monazite ages, potentially related to east-west compression that affected much of the central Rae Craton at this time.
Summary(Plain Language Summary, not published)
Thermobarometric and in situ SHRIMP monazite geochronology provide first-order constraints on the tectonometamorphic evolution of Melville Peninsula, with the data constraining two distinct metamorphic and deformational events. The first tectonometamorphic event is dated at ca. 2540 Ma, and is attributed to the early stages of the ca. 2.54 - 2.3 Ga Arrowsmith orogeny. The second event is dated between ca. 1860 and 1820 Ma, with textures suggesting that deformation occurred between ca. 1840 - 1825 Ma. Petrological calculations for one sample define a clockwise P-T-t path, consistent with metamorphism being driven by crustal thickening which is attributed to ca. 1870 Ma collision of the southeastern flank of the Rae with Meta Incognita microcontinent. Four samples from northern MP record somewhat (ca. 1815 Ma) to significantly (ca. 1798 - 1767 Ma) younger monazite ages.
GEOSCAN ID295852