Fluvial, lacustrine and volcanic sedimentation in the Angikuni sub-basin, and initiation of 1.84–1.79 Ga Baker Lake Basin, western Churchill

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• 作者：Aspler ; Lawrence B. ; Chiarenzelli ; Jeffrey R. ; Cousens ; Brian L.
• 关键词：Alluvial fan ; Fluvial ; Sand flat ; Lacustrine ; Magnesite ; Ultrapotassic magmatism ; Western Churchill Province
• 刊名：Precambrian Research
• 出版年：2004
• 出版时间：March 10, 2004
• 年：2004
• 卷：129
• 期：3-4
• 页码：225-250
• 全文大小：2.65 M

文摘

Continental siliciclastic and volcanogenic deposits of the Baker Lake Group accumulated in numerous sub-basins in the interior of the western Churchill Province between 1.84 and 1.79Ga. In the Angikuni sub-basin, on the southeast flank of greater Baker Lake Basin, Baker Lake Group rocks outcrop in two segments that extend northeast from Angikuni Lake. They are also exposed in scattered outliers throughout the region. At northern Angikuni Lake in the northern segment, conglomerates, pebbly sandstones and mudrocks of the Angikuni Formation unconformably overlie Archean basement, and are unconformably overlain by ultrapotassic volcanic and siliciclastic rocks of the Christopher Island Formation. These rocks record alluvial fan-fluvial and sand flat-playa deposition in a fault-bounded trough formed adjacent to a wedge-shaped basement uplift. Although the Angikuni Formation was tilted before principal Christopher Island Formation volcanism at northern Angikuni Lake, geochemical and Nd isotopic data from mudrocks indicate derivation from earlier or coeval Christopher Island volcanic-like sources. The outliers demonstrate that faulting produced significant changes in the structural level of Archean basement before Christopher Island Formation volcanism.