GEOL100
5-1-06
Continental glaciers and Ice ages

Land forms resulting from continental glaciers: Continental scale glaciation creates interesting opportunities for ice to interact with large volumes of sediment. Results include:

Ice ages:

Cretaceous was a greenhouse world. From the Eocene onward, there has been some evidence of valley glaciation, at least in parts of Antarctica. It seems that the switch from greenhouse to ice house conditions occurred during that interval. During last 1 - 2 million years, the situation has become extreme, with major continental glaciations alternating with interglacials. The interval from 2 mya to 10,000 years ago is called the Pleistocene Epoch.

Pleistocene glacial sequences: During mid- 19th century, Louis Agassiz first recognized widespread glacial deposits in Europe, and proposed former "ice ages" By turn of century, geologists had identified four major glacial intervals, which were punctuated by interglacials. These periods were pieced together by careful mapping a study of glacial landforms.

The Oxygen isotope record: During the late 20th century, a new technique allowed us to refine this sequence.

Condition 18,000 years ago during the last glacial maximum:

To see more about the animals that the first Americans lived with, check out this link.

Causes of the ice ages:

Ice ages seem to be driven by three basic considerations: Milankovitch cycles, continental configurations, and positive feedback.

The Ice-Age is still with us:

In this and many other lectures, we discuss various natural processes and patterns as if the Earth were at equilibrium. The fact is that it isn't. We can list ways in which equilibration is still occurring:

The future: Had the industrial revolution not occurred, this would still be a complex topic. What is known is that:

Now for something cool.