What cone of debris deposited by running water at the mouth of canyon in an arid area is known as?

The cone of debris deposited by running water at the mouth of a canyon in an arid area is known as an "alluvial fan." This geological formation occurs when sediment-laden water flows out of a narrow canyon and spreads out, losing energy and depositing sediments. Alluvial fans typically have a fan-shaped appearance and can vary in size and composition based on the sediment supply and water flow.