Glacial Transport and Deposition

Glaciers transport vast quantities of rock debris, ranging from fine clay particles to house-sized boulders. When this material is deposited, it creates a distinctive suite of landforms that dominate lowland glaciated landscapes. Understanding how glaciers carry and deposit sediment is essential for interpreting both upland and lowland glacial environments.

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Glacial Transport

Rock debris enters a glacier through several pathways and is carried in three main positions:

Supraglacial Transport

Material carried on the surface of the glacier:

• Derived mainly from freeze-thaw weathering of exposed valley sides above the glacier
• Rock fragments fall as scree onto the glacier margins, forming lateral moraines
• When two glaciers merge, adjacent lateral moraines combine to form a medial moraine — a dark streak running along the centre of the combined glacier
• Supraglacial debris is typically angular and unsorted because it has not been subject to abrasion

Englacial Transport

Material carried within the body of the glacier:

• Supraglacial debris may be buried by snowfall or fall into crevasses, becoming incorporated into the ice
• This material is transported passively within the glacier
• Englacial debris is also typically angular

Subglacial Transport