Which geomorphic outcome develops when sediment discharge abruptly decreases on debris fans originating from narrow canyons?

💡 Explanation

When sediment supply decreases abruptly, the stream on the fan lacks sufficient material to deposit and maintain its elevation, causing active downcutting and resulting entrenched channels into the existing fan surface. Therefore, entrenched channels form, rather than change in sediment sorting, fan angle increase which requires high sediment load or migration from higher sinuosity streams.

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