New Age Control on the Port Huron Moraine in Northern Michigan

The distribution of silty soils in the Grayling Fingers region of Michigan: Evidence for loess deposition onto frozen ground

“…The explanation given for this lack of post-glacial loess in Michigan has always been that most meltwater streams here were too short to have supplied adequate amounts of silt and/or that they quickly terminated into a proglacial lake, forcing any silt they may have been carrying to settle out within the lakes proper (Karrow and Calkin, 1985;Larson and Schaetzl, 2001). However, this scenario can be refuted for northern Lower Michigan, where Port Huron meltwater flowed subaerially as braided streams across vast outwash surfaces, around and between the Fingers, for perhaps a century or more (Blewett et al, 1993;Blewett and Winters, 1995;Fig. 2).…”

The Grayling Fingers region of Michigan: soils, sedimentology, stratigraphy and geomorphic development

“…The Port Huron ice advanced to its farthest point ca. 13 ka (Blewett, 1991;Blewett et al, 1993;Blewett and Winters, 1995). The Port Huron head of outwash forms a conspicuous ridge on three sides of the Fingers.…”

“…For example, the OSL ages on the Port Huron outwash, which is generally accepted to be c 13k radiocarbon YBP (Blewett et al, 1993), are constrained by the OSL method but overestimated by about 10 ka (Table 3). OSL dates from the main core of the Fingers provide a maximum constraining age of about 28 ka, which is reasonable and fits within the scenario of early Woodfordian deposition-at least for the upper parts of the outwash core.…”

Evidence for an eolian origin for the silt-enriched soil mantles on the glaciated uplands of eastern Upper Michigan, USA

“…The study area, in the eastern part of the Upper Peninsula of Michigan, was last deglaciated between ∼ 15,500 and 11,500 cal y BP (Drexler et al, 1983;Farrand and Drexler, 1985;Blewett et al, 1993;Lowell et al, 1999). With one exception (Blewett and Rieck, 1987), the glacial history of this region has been minimally studied.…”