Which mechanism limits cirque expansion rate as alpine glacial ice melts over decades?

💡 Explanation

When glacial ice thins, the debris covering the valley floor increases because the ice no longer transports it away. Thus, a debris layer insulates the remaining ice, reducing the localized ablation responsible for erosion extending the cirque. Therefore, increased debris cover limits expansion, decreasing freeze-thaw effects, basal sliding, and aggradation.

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