Glacial Lake Ontonagon and the Development of Large Scale Landslides

Glacial Lake Ontonagon and the Development of

Large Scale Landslides

Stan Vitton, PhD, PEMichigan Technological University

Adapted from a presented given at the 59th Annual MeetingInstitute for Lake Superior GeologyHoughton, MI May, 2013

Glacial Lake Ontonagon

• Location

• Glacial Lake Ontonagon

• Spring 2004 Landslide Event

• Landslide Initiation Mechanism

• Summary

Glacial Lake Ontonagon

US-45

Ottawa National Forest Boundary

Landslide Location

US-45

M-26

Rockland, MI

Ontonagon Landslide US-45 and the East Branch of the Ontonagon River

Landslide Location

Original Lake

Ontonagon Drainage

Ontonagon Drainage System

West Branch

Middle Branch

East Branch

South Branch

Landforms of the Upper Peninsula, Draft 2006

Major Landforms

Bedrock Geology of Upper Michigan

Landforms of Upper Michigan

Ontonagon Area - Landforms

USGS Professional Paper 504-BPostglacial Drainage and Stream Geometry of the Ontonagon AreaHack (1965)

USGS Professional Paper 504-B

USGS Professional Paper 504-B

US Corps of Engineers (2010)

Google Earth

Ontonagon Boulder

Glacial Lake Ontonagon

• Location

• Glacial Lake Ontonagon

• Spring 2004 Landslide Event

• Landslide Initiation Mechanism

• Summary

Glacial History of the Great Lakes

Farrand & Drexler, 1985, Late Wisconsin & Holocene History of the Lake Superior Basin

Farrand & Drexler, 1985, Late Wisconsin & Holocene History of the Lake Superior Basin

Farrand & Drexler, 1985, Late Wisconsin & Holocene History of the Lake Superior Basin

Farrand & Drexler, 1985, Late Wisconsin & Holocene History of the Lake Superior Basin

Farrand & Drexler, 1985, Late Wisconsin & Holocene History of the Lake Superior Basin

Farrand & Drexler, 1985, Late Wisconsin & Holocene History of the Lake Superior Basin

Prehistoric climate change due to cosmic crash in Canada September 3, 2013

An artist's rendition of mastodons, camels and a ground sloth before the environmental changes of the Younger Dryas led to their extinction. - Barry Roal Carlsen, University of Wisconsin

The impact occurred about 12,900 years ago, at the beginning of the Younger Dryas period, and marks an abrupt global change to a colder, dryer climate with far-reaching effects on both animals and humans. In North America, the big animals all vanished, including mastodons, camels, giant ground sloths and saber-toothed cats.

Their human hunters, known to archaeologists as the Clovis people, set aside their heavy-duty spears and turned to a hunter-gatherer subsistence diet of roots, berries and smaller game.

"The Younger Dryas cooling impacted human history in a profound manner," says Dartmouth Professor Mukul Sharma, a co-author of the study. "Environmental stresses may also have caused Natufians in the Near East to settle down for the first time and pursue agriculture."

It is not disputed that these powerful environmental changes occurred, but there has long been controversy over their cause. The classic view of the Younger Dryas cooling interlude has been that an ice dam in the North American ice sheet ruptured, releasing a massive quantity of freshwater into the Atlantic Ocean. The sudden influx is thought to have shut down the ocean currents that move tropical water northward, resulting in the cold, dry climate of the Younger Dryas.

But Sharma and his co-authors have discovered conclusive evidence linking an extraterrestrial impact with this environmental transformation. The report focuses on spherules, or droplets of solidified molten rock expelled by the impact of a comet or meteor. The spherules in question were recovered from Younger Dryas boundary layers at sites in Pennsylvania and New Jersey, the layers having been deposited at the beginning of the period. The geochemistry and mineralogy profiles of the spherules are identical to rock found in southern Quebec, where Sharma and his colleagues argue the impact took place.

Glacial Lake Ontonagon

• Location

• Glacial Lake Ontonagon

• Spring 2004 Landslide Event

• Landslide Initiation Mechanism

• Summary

Large Scale Landslide

Lower Unit Alluvial Sand

Upper Unit – Lacustrine

Upper Unit – Lacustrine

Upper Unit – Lacustrine

Upper Unit – Lacustrine

Lower Unit Alluvial Sand

Lower Unit Alluvial Sand

0.0100.1001.00010.0000

10

20

30

40

50

60

70

80

90

100

Upper Sand Layer 790 foot

Upper Sand Layer 760 foot

Middle Sand Layer 730 foot

Lower Sand Layer 710 foot

Grain Size, (mm)

Perc

ent P

assin

g, (%

)

Lower Unit Alluvial Sand

Glacial Lake Ontonagon

• Location

• Glacial Lake Ontonagon

• Spring 2004 Landslide Event

• Landslide Initiation Mechanism

• Summary

Lower Unit Alluvial Sand

Upper Unit – Lacustrine

0.0100.1001.00010.0000

10

20

30

40

50

60

70

80

90

100

Upper Sand Layer 790 foot

Upper Sand Layer 760 foot

Middle Sand Layer 730 foot

Lower Sand Layer 710 foot

Grain Size, (mm)

Perc

ent P

assin

g, (%

)

Lower Unit Alluvial Sand

Clay/Silt Softening at Base of the Slope

Soil Liquefaction in the Transition Zone

Glacial Lake Ontonagon

• Location

• Glacial Lake Ontonagon

• Spring 2004 Landslide Event

• Landslide Initiation Mechanism

• Summary

Thanks!

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