Glaciers move boulders through a process called glacial erosion and transport.
The Glacial Movement Mechanism
Glaciers are powerful forces of nature. Their movement is responsible for transporting massive amounts of rock and sediment, including boulders. This happens in a few key steps:
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Erosion: As a glacier moves, it acts like a giant bulldozer, scraping across the Earth's surface. This process, called glacial erosion, breaks apart bedrock and creates debris. The ice itself acts as an abrasive, grinding away at the rock.
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Entrainment: The eroded rock fragments, including boulders, become embedded within the ice. This process is known as entrainment. The ice acts as a powerful conveyor belt, carrying the debris along with it.
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Transportation: As the glacier flows downhill, it carries the entrained boulders and other rock fragments down the slope. The size and weight of the boulder does not significantly affect its transport as long as it is entrained within the ice.
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Deposition: When the glacier melts or retreats, the boulders and other debris are deposited, creating landforms like moraines. These are accumulations of sediment left behind by the moving glacier.
Example: Imagine a large boulder sitting on a mountainside. A glacier flows over the boulder, eroding the surrounding rock. The boulder itself becomes embedded in the ice. As the glacier moves, it carries the boulder downhill, eventually depositing it in a new location when the ice melts.
Key takeaway: Glaciers don't "lift" boulders; they incorporate them into their mass through erosion and then transport them through glacial flow. The ice's immense weight and movement are responsible for this powerful geological process. As noted in the provided reference, "As a glacier or ice sheet moves, it can erode bedrock. The ice can then pick up, or entrain, the eroded rock. As the ice flows, it transports the bedrock debris in the direction of flow."
