Which process primarily causes the rounded shape of cirque basins after glacial retreat?

💡 Explanation

When a glacier occupies a cirque, abrasion by rotational ice movement against the bedrock causes the rounded shape because the glacier grinds and polishes the surface under pressure as it moves. Therefore abrasion from ice results, rather than frost wedging, solifluction or chemical weathering, which are less dominant glacial processes.

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• Which outcome occurs when freshwater inflow reduces surface density within an ocean gyre?
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• Which mechanism accelerates surface deformation when permafrost thawing induces solifluction on an Arctic slope with ice wedges?
• Which phenomenon enhances coastal upwelling along the western margins of continents due to Ekman transport effect?