Revised time-distance diagram for the Lake Michigan Lobe, Michigan Subepisode, Wisconsin Episode, Illinois, USA

Abstract Glacial deposits of the last glaciation associated with the Harvard sublobe (Lake Michigan lobe) in northeastern Illinois, U.S.A., occur between sediment with dateable organics. The lower organics include fragments of Picea sp. as young as 24 000 ± 270 BP. The supraglacial organics occur sparsely in laminated silt and fine sand in landforms that are positioned relatively high on the landscape, such as deposits from ice-walled lakes. These terrestrial organics yield ages that are 2500 to 1300 14C years older than organics at the base of sediment successions in nearby kettle basins. Basal 14C ages from four upland sites range from 17 610 ± 270 to 16 120 ± 80 BP. Our revised time-distance diagram of the Harvard sublobe now reflects a period of stagnation from 24 000 to about 17 600 BP. The supraglacial lacustrine silt yielded plant macrofossil assemblages of primarily tundra plants, including Salix herbacea and Dryas integrifolia. These plants likely grew in supraglacial and ice-marginal environments. The ostracode fauna include Cytherissa lacustris and Limnocythere friabilis. Geomorphic relations and ostracode ecology indicate that more than 17 m of ice buttressed some of the supraglacial lakes.

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RECENT CHANGES TO THE TIME-DISTANCE DIAGRAM OF THE LAKE MICHIGAN LOBE (MICHIGAN SUBEPISODE, WISCONSIN EPISODE)

10.1130/abs/2016nc-275575 ◽

2016 ◽

Author(s):

Brandon Curry ◽

◽

Henry M. Loope ◽

Thomas V. Lowell ◽

Hong Wang ◽

...

Keyword(s):

Lake Michigan ◽

Time Distance ◽

Lake Michigan Lobe

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PROVENANCE VARIATION IN A LAURENTIDE ICE SHEET LAKE MICHIGAN LOBE DEPOSIT, PETRIFYING SPRINGS, KENOSHA, WISCONSIN

10.1130/abs/2016nc-275436 ◽

2016 ◽

Author(s):

Andi MacAlister ◽

◽

Rachel Headley

Keyword(s):

Lake Michigan ◽

Ice Sheet ◽

Laurentide Ice Sheet ◽

Provenance Variation ◽

Lake Michigan Lobe ◽

Lobe Deposit

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Absence of Glaciation in Illinois during Marine Isotope Stages 3 through 5

Quaternary Research ◽

10.1006/qres.1996.0040 ◽

1996 ◽

Vol 46 (1) ◽

pp. 19-26 ◽

Cited By ~ 38

Author(s):

B. Brandon Curry ◽

Milan J. Pavich

Keyword(s):

Oxygen Isotope ◽

Late Stage ◽

Lake Michigan ◽

Early Stage ◽

Ice Sheet ◽

Laurentide Ice Sheet ◽

Argillic Horizon ◽

Late Wisconsinan ◽

Lake Michigan Lobe

A10Be inventory and14C ages of material from a core from northernmost Illinois support previous interpretations that this area was ice free from ca. 155,000 to 25,000 yr ago. During much of this period, from about 155,000 to 55,000 yr ago, 10Be accumulated in the argillic horizon of the Sangamon Geosol. Wisconsinan loess, containing inherited 10Be, was deposited above the Sangamon Geosol from ca. 55,000 to 25,000 yr ago and was subsequently buried by late Wisconsinan till deposited by the Lake Michigan Lobe of the Laurentide Ice Sheet. The Sangamonian interglacial stage has been correlated narrowly to marine oxygen isotope substage 5e; our data indicate instead that the Sangamon Geosol developed during late stage 6, all of stages 5 and 4, and early stage 3.

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Glacial-Lake Outburst Erosion of the Grand Valley, Michigan, and Impacts on Glacial Lakes in the Lake Michigan Basin

Quaternary Research ◽

10.1006/qres.1993.1004 ◽

1993 ◽

Vol 39 (1) ◽

pp. 36-44 ◽

Cited By ~ 26

Author(s):

Alan E. Kehew

Keyword(s):

Lake Level ◽

Lake Michigan ◽

Laurentide Ice Sheet ◽

Glacial Lake ◽

Michigan Basin ◽

Lake Agassiz ◽

Lake Algonquin ◽

Lake Michigan Lobe ◽

Possible Cause ◽

Glacial Lake Algonquin

AbstractGeomorphic and sedimentologic evidence in the Grand Valley, which drained the retreating Saginaw Lobe of the Laurentide Ice Sheet and later acted as a spillway between lakes in the Huron and Erie basins and in the Michigan basin, suggests that at least one drainage event from glacial Lake Saginaw to glacial Lake Chicago was a catastrophic outburst that deeply incised the valley. Analysis of shoreline and outlet geomorphology at the Chicago outlet supports J H Bretz's hypothesis of episodic incision and lake-level change. Shoreline features of each lake level converge to separate outlet sills that decrease in elevation from the oldest to youngest lake phases. This evidence, coupled with the presence of boulder lags and other features consistent with outburst origin, suggests that the outlets were deepened by catastrophic outbursts at least twice. The first incision event is correlated with a linked series of floods that progressed from Huron and Erie basin lakes to glacial Lake Saginaw to glacial Lake Chicago and then to the Mississippi. The second downcutting event occurred after the Two Rivers Advance of the Lake Michigan Lobe. Outbursts from the eastern outlets of glacial Lake Agassiz to glacial Lake Algonquin are a possible cause for this period of downcutting at the Chicago outlets.

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