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TitleNew U-Pb geochronological results from Hall Peninsula, Baffin Island, Nunavut
AuthorRayner, N M
SourceSummary of Activities 2013, Canada-Nunavut Geoscience Office; Canada-Nunavut Geoscience Office, Summary of Activities 2013, 2013 p. 39-52
Alt SeriesEarth Sciences Sector, Contribution Series 20130274
PublisherCanada-Nunavut Geoscience Office
File formatpdf
AreaHall Peninsula; Baffin Island
Lat/Long WENS -66.5000 -66.0000 63.5000 63.2500
Subjectsgeochronology; uranium lead dates; uranium lead dating; uranium lead ratios; bedrock geology; Archean; metasedimentary rocks; Precambrian
Illustrationslocation maps; photographs; photomicrographs; Concordia diagrams
ProgramCanada-Nunavut Geoscience Office, Funding Program
AbstractAges for ten bedrock samples from across southern Hall Peninsula,Baffin Island, Nunavut were determined by zircon U-Pb geochronology. Ages for the basement complex in the eastern portion of the peninsula include tonalite gneiss dated at 2841± 3 Ma and deformed megacrystic granite with a crystallization age of 2701 ±2 Ma. Four metasedimentary samples from locations across the peninsula are demonstrably Paleoproterozoic, with a significant 2.1-1.9 Ga zircon population and maximum ages of deposition that range from 2126 ±16 to 1906 ±9 Ma. A quartzite sampled from within the gneissic basement-dominated eastern half of the peninsula contains only Archean detritus and is interpreted to represent a locally sourced, basal clastic package. Metasedimentary rocks in the west are cut by extensive granulite-grade diorite to monzogranite dated at 1892 ±7 Ma. White-weathering monzogranite cutting psammite and amphibolite yields an age of 1873 ±6 Ma. Because this monzogranite was subsequently affected by a regionally pervasive, east-west shortening, deformation episode (D 1), this age is also a maximum age constraint on the timing of D1 deformation. A sample of weakly to undeformed leucogranite with distinct lilac-coloured garnet is dated at 1867 ±8 Ma, bracketing the end of D1.
Summary(Plain Language Summary, not published)
Knowledge of the age of rocks (geochronology) is critical in the making of a geologic map as it allows scientists to add the measurement of time to their field observations and permits comparisons with similar rocks elsewhere. This report presents ages from 10 samples across Hall Peninsula, southern Baffin Island, as part of a mapping project led by the Canada-Nunavut Geoscience Office in cooperation with the Geological Survey of Canada. The results include ages for tonalite gneiss, the rock type which is host to diamond-bearing kimberlites on Hall Peninsula. Sedimentary rocks across the entire width of Hall Peninsula are shown in this report to be Paleoproterozoic in age (approx. 2 billion years). These rocks are prospective for base and/or precious metals and are similar in age and appearance to sedimentary rocks to the west that host coloured gemstones. The results presented in this report contribute to the overall understanding of the geological framework and mineral exploration potential of Hall Peninsula, thereby reducing risk to exploration and resource development.