Minimum limiting deglacial ages for the out-of-phase Saginaw Lobe of the Laurentide Ice Sheet using optically stimulated luminescence (OSL) and radiocarbon methods

Abstract

Twenty-four new optically stimulated luminescence (OSL) and radiocarbon ages from sediment cores in nine lakes associated with the Shipshewana and Sturgis moraines in northern Indiana and southern Michigan estimate when recession of the Saginaw Lobe of the Laurentide Ice Sheet was underway in the southern Great Lakes region, USA. Average OSL ages of 23.4 ± 2.2 ka for the Shipshewana Moraine and 19.7 ± 2.2 ka for the Sturgis Moraine are considered minimum limiting deglacial ages for these recessional moraines. The much younger radiocarbon ages are consistent with other regional radiocarbon ages from lakes, and record climate amelioration around ~16.5 cal ka BP. Early recession of the interlobate Saginaw Lobe was well underway by 23.4 ± 2.2 ka, when the adjacent Lake Michigan and Huron-Erie lobes were a few hundred kilometers farther south and near their maximum southerly limits. The results provide the first time constraints when sediment from the Lake Michigan and Huron-Erie lobes began filling the accommodation space left by the Saginaw Lobe. The difference between the oldest radiocarbon and OSL age is 7400 yr for the Shipshewana Moraine and 3400 yr for the Sturgis Moraine.

New age constraints reveal moraine stabilization thousands of years after deposition during the last deglaciation of western New York, USA

“…Our findings support the observations and conclusions from numerous studies that radiocarbon dates can be extreme minimum age constraints on deglaciation (Curry et al, 2018;Fisher et al, 2020;Florin and Wright, 1969;Halsted et al, 2023;Yansa et al, 2020). In New England, minimum-limiting radiocarbon ages may be the reason for the discrepancy between the timing of moraine deposition as recorded by 10 Be exposure dating (e.g., Balco et al, 2002;Corbett et al, 2017) and radiocarbon ages of basal macrofossils in lakes and bogs (e.g., Peteet et al, 2012).…”

“…The warming at the Bølling onset at ~14.7 ka may have increased regional temperatures, causing the melting of buried ice, initiating a phase of rapid landscape evolution and the formation of kettle basins, and eventually stabilizing the morainal topography. Numerous studies discuss the role of permafrost in the lag time between moraine ages and basal macrofossils along the south-central LIS margin, including Indiana and Illinois (Curry et al, 2018;Fisher et al, 2020), Michigan (Yansa et al, 2020), and Wisconsin (Clayton et al, 2008).…”

Chronology and stratigraphy of the Imlay Channel in Lapeer County, Michigan, USA

“…procedures (Murray and Wintle 2000;Wintle and Murray 2006). Sample preparation, instrument details, and data analysis methodology are described in more detail in the supplement to Lepper et al (2007) as well as in Fisher et al (2020). Dose rates were calculated following the methods presented in Aitken (1985Aitken ( , 1998 and Hutton (1988, 1994) and presented in Tables 2 and 3.…”

“…1A). For nearly 50 years this single age has been used to constrain the deglacial history in southeastern Michigan, and the same age is found at several sites in south central Michigan (Fisher et al 2020), including an OSL age of 16.8 ± 1.0 ka from a glacial Lake Maumee strandline in northwestern Ohio (Fisher et al 2015). The age from the Weaver Drain site has also been used to date cessation of water flow through the Imlay channel (Burgis 1970;Buckley and Willis 1972;Fullerton 1980;Calkin and Feenstra 1985).…”

Early Holocene ice retreat from Isle Royale in the Laurentian Great Lakes constrained with 10Be exposure-age dating

“…Ice retreat through the Great Lakes appears to have been mostly continuous across the late-Pleistocene-Holocene transition (Lowell et al, 2021) with some clear exceptions of ice advance during the Marquette Readvance of the Younger Dryas (Loope, 2006;Lowell et al, 1999Lowell et al, , 2009. Meltwater from the LIS accounts for ~50-60% of the late-Pleistocene sea-level budget (Clark and Mix, 2002), so constraining spatial and temporal retreat patterns of the LIS southwest margins through the Great Lakes improves understanding of meltwater routing from proglacial lakes to the oceans (Broecker, 2006;Broecker et al, 1989;Carlson et al, 2007;Fisher, 2020;Leydet et al, 2018;Teller, 1990;Teller and Mahnic, 1988;Teller et al, 2002Teller et al, , 2005 and proglacial lake organization (Breckenridge, 2013;Farrand, 1969).…”