Which geomorphologic feature forms when stranded blocks of glacial ice melt on outwash plains, creating depressions that fill with water?

Which geomorphologic feature forms when stranded blocks of glacial ice melt on outwash plains, creating depressions that fill with water?

• A. Moraine-dammed lakes
• B. Tarn lakes
• C. Cirques
• D. Kettle lakes

Answer: (D)

Kettle lakes form when stranded blocks of glacial ice melt on outwash plains, creating depressions that fill with water. As the ice chunks buried in the meltout sediments melt, they leave behind hollow, seepage-prone spots that become small, water-filled lakes or ponds. This process is typical of the flat, stratified sands and gravels of an outwash plain left by retreating glaciers, and the resulting lakes are often irregular in shape with surrounding hummocky debris. This differs from moraine-dammed lakes, which are held back by a moraine ridge rather than by melted ice blocks; tarn lakes, which occupy bedrock basins in mountainous regions carved by glaciers; and cirques, which are large bowl-shaped hollows formed by glacial erosion high on mountain sides.

Kettle lakes form when stranded blocks of glacial ice melt on outwash plains, creating depressions that fill with water. As the ice chunks buried in the meltout sediments melt, they leave behind hollow, seepage-prone spots that become small, water-filled lakes or ponds. This process is typical of the flat, stratified sands and gravels of an outwash plain left by retreating glaciers, and the resulting lakes are often irregular in shape with surrounding hummocky debris.

This differs from moraine-dammed lakes, which are held back by a moraine ridge rather than by melted ice blocks; tarn lakes, which occupy bedrock basins in mountainous regions carved by glaciers; and cirques, which are large bowl-shaped hollows formed by glacial erosion high on mountain sides.