Which process of glacial erosion involves the removal of large masses of ice?

The process of glacial erosion that involves the removal of large masses of ice is known as plucking. This occurs when a glacier moves over the landscape and exerts pressure on the underlying rock. As the glacier advances, it can cause fractures in the rock, and when the ice melts partially at the base due to pressure or other factors, the water can infiltrate these fractures. As the glacier continues to move, it can lift or "pluck" blocks of rock out of the ground, effectively removing large masses of rock and substrate. This is a significant mechanism by which glaciers reshape the land beneath them, creating features such as striations and streamlined valleys.

In contrast, debris flow refers to the movement of mixed sediment and water down slopes, which is more associated with gravity-driven processes rather than ice dynamics. Subglacial melt pertains to the melting of ice at the base of the glacier, which does not directly involve the removal of large masses of ice. Weathering involves the breakdown of rocks at the Earth's surface through various processes, but it does not specifically relate to glaciers or their movement. Thus, plucking is the most appropriate answer when discussing the removal of large masses of ice by glacial action.