How do glacier retreat?

Question

I am studying Dynamic Processes in Earth Science, and I need help with my homework. Does anyone know how glaciers retreat?

Answer 1

When a glacier retreats it does so because the melting ice at the foot of the glacier is melting faster than it is replaced by snow at it's head.

Interestingly, the ice itself continues to move forward, but the foot of the glacier moves back. How is this possible?

Well, consider a big bologna, and a hand-held slicer. If one person forces the bologna forward (movement of ice) and the slicer (the melt line) moves backward there is a situation analagous to the glacier: the ice (bologna) continues to move away from the source, while the foot of the glacier (the meat slicer) moves back, toward the source.

Answer 2

A glacier is constantly in motion, albeit very slow. Think of it as a very thick pile of cold molasses. Gravity pulls on it to move from the top of the mountain. How far down depends on factors such as temperature which causes melting, slope which affects speed of movement, and the resupply of snow mass.

The "health" of the glacier can be measured by the position of the terminal moraine if on land. If this starts to recede back up the mountain, then the glacial mass is reducing. The glacier never moves up (retreats) its flow is always down hill, however the position of the terminus can move up.

Answer 3

They melt.

The bottom of the glacier is at the lowest altitude (ice flows downhill), so the air near the bottom of the mountain is warmer than near the top.

Answer 4

Good question. Maybe they just want use to think they're retreating when they are growing taller. I guess you should look at the total mass. How smart are those glaciers? Sneaky devils.

Answer 5

They melt faster than the accumulated ice and snow causes them to advance - thus "retreating"

Answer 6

They Melt.