Which mechanism causes the formation of hanging valleys within a fjord's upper reaches?

💡 Explanation

When tributary glaciers merge with the main fjord glacier, differential erosion occurs because the smaller glaciers erode less deeply than the main glacier, leaving valleys elevated above main fjord floor. Therefore, differential erosion explains hanging valleys, rather than rebound, uplift or sea-level drop, requiring different geomorphological processes.

• Which mechanism causes thermokarst formation when permafrost thaws under impermeable layers disrupting landscape stability?
• Which outcome occurs when increased rainfall amplifies earthworm bioturbation?
• Which risk increases when a subtropical gyre's surface temperature gradient weakens significantly?
• Prolonged rainfall increases stress on river levees, causing which failure mode when shear strength decreases?
• Which outcome increases proximal fault stress when stick-slip behavior occurs?
• Which process generates elevated methane release from thermokarst lake formation in arctic permafrost regions?