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Title Investigating potential climatic cycles in glacially-influenced rhythmites of the upper Gowganda Formation using geochemical, sedimentological and spectral analyses
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Publication Date
University/Publisher University of Western Ontario
Abstract The upper Gowganda Formation of the Huronian Supergroup contains glacially-induced, varve-like rhythmites composed of turbiditic micro-laminae that potentially preserve a detailed record of climatic conditions during the Paleoproterozoic Era. A sedimentological analysis of upper Gowganda Formation deposits enabled identification of eight lithofacies comprising a glaciogenic depositional environment: 1) diamictite, 2) contorted argillite, 3) interlaminated siltstone and sandstone, 4) interbedded siltstone and claystone, 5) sandstone, 6) siltstone, 7) interbedded coarse-grained and fine-grained siltstone, and 8) wavy argillite. Major, trace, and rare earth element analyses indicate that the rhythmites have undergone limited recycling and chemical alteration. Whole-rock δ18O values are consistent with an Archean gneiss provenance and support that chemical weathering and diagenesis were insignificant. Spectral analysis of four rhythmic couplet thickness records using the MTM Toolkit of Mann and Lees (1996) supports the hypothesis of annual deposition for the rhythmites.
Subjects/Keywords Paleoproterozoic; Huronian; glaciation; rhythmites; varves; micro-laminae; Geology
Language en
Country of Publication ca
Format application/pdf
Record ID oai:ir.lib.uwo.ca:etd-4660
Repository uwo
Date Retrieved
Date Indexed 2020-06-19

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…43 Figure 3-8: A: Micro-laminae in claystone (clst) layers in the lower section of the interbedded siltstone and claystone lithofacies at Outcrop A are defined by thin layers of siltstone (slst) that separate individual lamina…

…Siltstone micro-laminae are separated by thin claystone layers. B: Micro-laminae in the fine-grained siltstone (f-slst) layers of the interbedded coarse-grained and fine-grained siltstone lithofacies at Outcrop B are defined by thin layers of…

…coarse siltstone (c-slst) that separate individual fine-grained siltstone lamina. C, D: Micro-laminae in claystone layers in the lower section of the interbedded siltstone and claystone lithofacies at Outcrop C (C) and Outcrop A (…

…D) are defined by thin layers of siltstone that separate individual laminae. Thicker siltstone laminae ix dividing claystone layers were observed locally. Siltstone micro-laminae are separated by thin claystone or fine-grained siltstone layers…

…44 Figure 3-9: A: Flame (flm) structures in fine-grained siltstone (f-slst) laminae, irregular bedding and an increase in the prevalence of coarse-grained siltstone (c-slst) laminae upsection in the interbedded coarse…

…siltstone laminae are also displayed upsection. Claystone (clst) laminae grade to fine-grained siltstone laminae upsection (C). D: Photomicrograph of the upper section of the interbedded siltstone and claystone lithofacies at Outcrop C…

…in solar UV radiation associated with sunspot peaks may influence climate patterns; however this correlation has not been conclusively demonstrated (Weedon, 2003). Micro-banded deposits in the Paleoproterozoic banded-iron formation of the…

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