U–Pb geochronology of the MacQuoid supracrustal belt and Cross Bay plutonic complex: Key components of the northwestern Hearne subdomain, western Churchill Province, Nunavut, Canada

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• 作者：William J. Davis ; Simon Hanmer ; Subhas Tella ; Hamish A. Sandeman and James J. Ryan
• 关键词：Geochronology ; Western Churchill ; Rae ; Hearne ; Tectonic evolution
• 刊名：Precambrian Research
• 出版年：2006
• 出版时间：5 March 2006
• 年：2006
• 卷：145
• 期：1-2
• 页码：53-80
• 全文大小：1932 K

文摘

New geological and geochronological data from the MacQuoid supracrustal belt and the geometrically overlying Cross Bay plutonic complex highlight a distinct tectonothermal evolution for the northwestern part of the Hearne domain (northwestern Hearne subdomain), compared with adjacent areas in the Rae and Hearne, of the western Churchill Province, Canada. The supracrustal and intrusive rocks dominantly formed in the Neoarchean between <2.74 and 2.65 Ga, with minor 2.61 Ga granite, and experienced a polycyclic Neoarchean and Paleoproterozoic deformational history. The dominant tectonic fabric throughout much of the area formed between 2.56 and 2.50 Ga, including the Big Lake shear zone, a granulite-facies mylonite zone that juxtaposed the Cross Bay plutonic complex over the MacQuoid supracrustal belt at 2.50 Ga. The fabric transposed earlier fabrics whose age is poorly constrained. Additional tectonic events occurred during the Paleoproterozoic at 1.90 Ga, and 1.84–1.81 Ga. Differences between the geological histories of the northwestern part of the Hearne domain relative to the immediately adjacent Rae and Hearne areas highlight the tectonically distinct character of the northwestern Hearne subdomain.