Context: Glaciers are broken into zones based on surface snowpack and melt conditions. The ablation zone is the region where there is a net loss in glacier mass. The equilibrium line separates the ablation zone and the accumulation zone; it is the altitude where the amount of new snow gained by accumulation is equal to the amount of ice lost through ablation. The upper part of a glacier, where accumulation exceeds ablation, is called the accumulation zone. In general, the accumulation zone accounts for 60–70% of the glacier's surface area, more if the glacier calves icebergs. Ice in the accumulation zone is deep enough to exert a downward force that erodes underlying rock. After a glacier melts, it often leaves behind a bowl- or amphitheater-shaped depression that ranges in size from large basins like the Great Lakes to smaller mountain depressions known as cirques.

Question: What characteristics determine glacial zones?
Answer: surface snowpack and melt conditions

Question: Which glacial zone area reports a net-loss in glacial mass?
Answer: ablation zone

Question: What is the name of the line seperating the ablation zone from the accumulation zone?
Answer: equilibrium line

Question: How much glacial surface area is typically considered accumulation zone?
Answer: 60–70%

Question: What is based on suface ice and melt conditions?
Answer: Unanswerable

Question: Wht line marks the center of the glacier?
Answer: Unanswerable

Question: What does the abilation zone cover 60-70% of?
Answer: Unanswerable

Question: What forces underlying rock upward?
Answer: Unanswerable

Question: What lakes where formed from a mountain depression
Answer: Unanswerable