Which mechanism directly initiates cirque formation in orogenic zones?

💡 Explanation

Nivation initiates cirque formation because freeze-thaw cycles mechanically weather and erode bedrock, forming a hollow. This process then allows glacial ice to accumulate and further erode the depression via glacial erosion, rather than tectonic uplift or crustal rebound, which alter landscape elevation.

• Which outcome occurs when pyroclastic surges encounter an inland lake?
• Which boundary change results when thermal expansion weakens subtropical gyre stream flows?
• Which erosion outcome primarily results when exposed granite undergoes chemical alteration?
• Which outcome occurs when levee construction obstructs sediment transport?
• Which horizon differentiation occurs when intense chemical weathering?
• Which risk increases when a large earthquake causes liquefaction in loosely packed, water-saturated soil?