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DOI	10.1016/j.quascirev.2020.106590
	Subtill nonglacial deposits and their climatic implications for the Last Interglacial (MIS 5e); Hudson Bay Lowlands; Canada
	Gao C.; Huot S.; McDonald A.M.; Crabtree D.C.; Turton C.L.
发表日期	2020
ISSN	0277-3791
卷号	248
英文摘要	In Hudson Bay Lowlands (HBL), the Wisconsinan tills are often underlain by organic-bearing nonglacial deposits formed during episodes of significant reduction of ice volumes or complete ice-free conditions in this region. The subtill nonglacial deposits, often correlated with the Missinaibi Formation, are beyond the method limit of radiocarbon dating in general. As such, they have been a subject of debates for their stratigraphy and associated climatic conditions owing to poor age constraints. Extensive studies were undertaken on a subtill argillaceous lacustrine deposit uncovered recently on the Winisk River. This 9 m thick organic-rich deposit, referred to as the Webequie Beds, was dated at 121 ± 9 ka, 126 ± 24 ka and 105 ± 11 ka using optically stimulated luminescence (OSL) dating method and correlated with the Last Interglacial (LIG) or Marine Isotope Stage (MIS) 5e. Pollen and plant macrofossils suggest spruce boreal forests along with extensive wetlands, not unlike what exists in the HBL today. Of particular note is the sporadic rise of birch in the upper part of the pollen sequence, interpreted as a response to the availability of frequent forest clearance by fires under a warmer climate. The birch zone is noteworthy because it corresponds to the development of conspicuous S-rich, ferromagnetic nodules (0.125–1.5 mm diameter) in the lake sediment. The nodules comprise native sulphur and greigite (Fe3S4), along with iron oxyhydroxide goethite and lepidocrocite. They likely resulted from significant warming during this interval that enhanced microbial sulphate reduction and increased the release of H2S, an essential component for the formation of the S minerals in the lake. Besides the strengthened microbial metabolization, a prolonged summer lake stratification and development of an anoxic bottom water also likely promoted the sulphate reduction. Although confirmation is needed, the warming probably linked to the LIG thermal maximum (∼120 ka) when a climate with a higher summer temperature than today prevailed. A similar subtill nonglacial deposit on the Little Current, a tributary of the Albany River, was also examined for comparison. Apart from a similar pollen flora, S-rich nodules were also recovered near a horizon OSL dated at 118 ± 13 ka comparable to the LIG thermal maximum. Results of this study provide new insights into the stratigraphy and climatic conditions of the LIG in the HBL but also help better understand the behavior and dynamics of the Laurentide Ice Sheet during the Late Pleistocene. © 2020
英文关键词	Hudson Bay Lowlands; Lacustrine; Last Interglacial; MIS 5e; Pollen; S-rich nodules; Subtill nonglacial; Warming; Webequie Beds; Winisk River
语种	英语
scopus关键词	Forestry; Hydrogen sulfide; Ice; Iron compounds; Lakes; Luminescence; Plants (botany); Stratigraphy; Sulfur compounds; Climatic conditions; Ice-free conditions; Lacustrine deposits; Laurentide ice sheets; Marine isotope stages; Microbial sulphate reduction; Optically stimulated luminescence; Plant macrofossils; Deposits; bottom water; dating method; forest clearance; Hypsithermal; Last Interglacial; luminescence; pollen; radiocarbon dating; stratigraphy; Albany River; Canada; Hudson Bay Lowlands; Ontario [Canada]; Picea
来源期刊	Quaternary Science Reviews
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/151279
作者单位	Ontario Geological Survey, 933 Ramsey Lake Road, Sudbury, ON P3E 6B5, Canada; Illinois State Geological Survey, 615 E. Peabody Drive, Champaign, IL 61820, United States; Harquail School of Earth Sciences, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON P3E 2C6, Canada; Department of Natural History, Royal Ontario Museum, Toronto, ON M5S 2C6, Canada
推荐引用方式 GB/T 7714	Gao C.,Huot S.,McDonald A.M.,et al. Subtill nonglacial deposits and their climatic implications for the Last Interglacial (MIS 5e); Hudson Bay Lowlands; Canada[J],2020,248.
APA	Gao C.,Huot S.,McDonald A.M.,Crabtree D.C.,&Turton C.L..(2020).Subtill nonglacial deposits and their climatic implications for the Last Interglacial (MIS 5e); Hudson Bay Lowlands; Canada.Quaternary Science Reviews,248.
MLA	Gao C.,et al."Subtill nonglacial deposits and their climatic implications for the Last Interglacial (MIS 5e); Hudson Bay Lowlands; Canada".Quaternary Science Reviews 248(2020).