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TitleArchean magmatism and metamorphism of eastern Hall Peninsula, southern Baffin Island, Nunavut
AuthorFrom, R E; Rayner, N MORCID logo; Camacho, A
SourceCanada-Nunavut Geoscience Office, Summary of Activities 2015, 2015 p. 73-88 Open Access logo Open Access
LinksOnline - En ligne
Alt SeriesEarth Sciences Sector, Contribution Series 20150279
PublisherCanada-Nunavut Geoscience Office
File formatpdf
NTS25I; 25P
AreaHall Peninsula; Baffin Island
Lat/Long WENS -66.0000 -64.0000 64.0000 62.0000
Subjectsgeochronology; Archean; magmatism; magmatic rocks; metamorphism; radiometric dating; uranium lead dating; Precambrian
Illustrationslocation maps; photomicrographs; plots; tables
ProgramCanada-Nunavut Geoscience Office, Funding Program
AbstractZircon U-Pb geochronology was conducted on six distinct crustal units within a well-constrained study area on eastern Hall Peninsula, Baffin Island. The U-Pb isotopic ages range from ca. 3209 to 2682 Ma1, outlining a protracted period of Archean magmatic activity and highlighting the previously unrecognized heterogeneity of this orthogneiss suite. Integrating the U-Pb isotopic age data with high-resolution zircon imaging and Th/U ratios, several samples were interpreted to have both an Archean crystallization age and an Archean metamorphic-overprint age. Crystallization ages, characterized by prismatic zircon grains with well-defined oscillatory-growth zoning, range from ca. 2.98 to 2.75 Ga. Archean metamorphic-overprint ages, characterized by rounded zircon grains that are commonly unzoned or sector zoned, or have an irregular internal structure, range from ca. 2.74 to 2.68 Ga. Constraining the timing of Archean crystallization and metamorphism is a key step in fingerprinting the Archean orthogneiss complex of Hall Peninsula. The data can be used for comparison with adjacent Archean terrains, and correlations critical for paleoplate reconstructions for the Baffin Island and subarctic regions can be established.
Summary(Plain Language Summary, not published)
The oldest rocks on Hall Peninsula occur on the eastern portion of the peninsula. The geological history of these rocks remains largely unknown. These rocks were regionally mapped during 2013 and 2014 as part of large-scale project to produce an updated geological map of Hall Peninsula. During 2014, a small detailed mapping project was conducted to further characterize the oldest component of rocks present on Hall Peninsula. Analytical studies have been conducted on a set of rock specimens collected from the study area. Dating of the rocks using isotopes of uranium and lead was carried out to help us understand when they formed. This information is important with respect to the geological history of the region and to assist in exploration for the diamonds, base metals, gem-quality minerals and carving stone deposits that could occur within them. The results indicate that rocks on eastern Hall Peninsula range in age from about 2.97 to 2.69 billion years old.

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