Glacial Lake Ontonagon was one of the first pro-glacier lakes formed during the retreat of the Laurentide Ice Sheet during the end of the Wisconsin Glacial period. The lake was just south of present day Lake Superior but flowed westward toward the Mississippi River due to Lake Superior still being filled with ice. The lake form significant lacustrine deposit over lying a river sand. A recent large scale landslide occurred on an ox bow of the river, with the failure being generated by soil liquefaction in the lower sand unit.

1. Glacial Lake Ontonagon
and the Development of
Large Scale Landslides
Stan Vitton, PhD, PE
Michigan Technological University
Adapted from a presented given at the
59th Annual Meeting
Institute for Lake Superior Geology
Houghton, MI May, 2013

3. Glacial Lake Ontonagon
• Location
• Glacial Lake Ontonagon
• Spring 2004 Landslide Event
• Landslide Initiation Mechanism
• Summary

4. Glacial Lake Ontonagon
US-45

5. Ottawa National Forest Boundary
Landslide
Location
US-45
M-26
Rockland, MI

6. Ontonagon Landslide US-45 and the East
Branch of the Ontonagon River
Landslide Location

7. Ontonagon Drainage System

8. Landforms of the Upper Peninsula,
Draft 2006

9. Major Landforms

10. Bedrock Geology of Upper Michigan

11. Landforms of Upper Michigan

12. Ontonagon Area - Landforms

13. USGS Professional Paper 504-B
Postglacial Drainage and Stream Geometry of the Ontonagon Area
Hack (1965)

14. USGS Professional Paper 504-B

15. USGS Professional Paper 504-B

17. US Corps of Engineers (2010)

20. Google Earth

21. Ontonagon Boulder

22. Glacial Lake Ontonagon
• Location
• Glacial Lake Ontonagon
• Spring 2004 Landslide Event
• Landslide Initiation Mechanism
• Summary

23. Glacial History of
the Great Lakes

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

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

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

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

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

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

30. 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

31. 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.

32. "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.

33. 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.

34. Glacial Lake Ontonagon
• Location
• Glacial Lake Ontonagon
• Spring 2004 Landslide Event
• Landslide Initiation Mechanism
• Summary

35. Large Scale Landslide

43. Lower Unit
Alluvial Sand
Upper Unit – Lacustrine

44. Upper Unit – Lacustrine

45. Upper Unit – Lacustrine

46. Upper Unit – Lacustrine

47. Lower Unit Alluvial Sand

48. Lower Unit Alluvial Sand

50. 0
10
20
30
40
50
60
70
80
90
100
0.0100.1001.00010.000
PercentPassing,(%)
Grain Size, (mm)
Upper Sand Layer 790 foot
Upper Sand Layer 760 foot
Middle Sand Layer 730 foot
Lower Sand Layer 710 foot
Lower Unit Alluvial Sand

56. Glacial Lake Ontonagon
• Location
• Glacial Lake Ontonagon
• Spring 2004 Landslide Event
• Landslide Initiation Mechanism
• Summary

58. Lower Unit Alluvial Sand
Upper Unit – Lacustrine

62. 0
10
20
30
40
50
60
70
80
90
100
0.0100.1001.00010.000
PercentPassing,(%)
Grain Size, (mm)
Upper Sand Layer 790 foot
Upper Sand Layer 760 foot
Middle Sand Layer 730 foot
Lower Sand Layer 710 foot
Lower Unit Alluvial Sand

63. Clay/Silt Softening at Base of the Slope

64. Soil Liquefaction in the Transition Zone

65. Glacial Lake Ontonagon
• Location
• Glacial Lake Ontonagon
• Spring 2004 Landslide Event
• Landslide Initiation Mechanism
• Summary

66. Thanks!
Questions?