The 'basket of eggs' topography carved by ancient moving ice

Countries & Cities · Published 2 October 2026 Swipe more like this →

In short: Imagine a landscape of smooth, oval hills resembling an overturned spoon or a half-buried egg. These are drumlins—glacial landforms that act as frozen fingerprints of the Earth's climate history. By studying their orientation and shape, scientists can reconstruct the precise path and speed of massive ice sheets from thousands of years ago.

Drumlins are elongated hills typically measuring between 250 and 1,000 meters long and 120 to 300 meters wide. They primarily form from glacial till—a mix of clay, silt, sand, gravel, and boulders—deposited by moving ice. While many drumlins are composed of these soft sediments, some are formed entirely from hard bedrock like granite or limestone. This suggests that while accretion (adding material to a core) is one way they form, erosion (wearing away the land between hills) is another significant mechanism.

The physics of their formation is tied to glacier dynamics. In temperate glaciers, ice moves through both internal deformation and basal sliding. Because these glaciers are at the pressure-melting point, the ice can slide over the bed, allowing it to carve and shape the landscape effectively. The resulting drumlins often appear in 'swarms' or fields. Their specific geometry provides a data set for glaciologists: a longer, more elongated drumlin generally indicates slower glacier velocity, while shorter ones suggest faster movement.

These landforms serve as a geographical archive of the last ice age, which ended roughly 15,000 to 20,000 years ago. During this period, over 30 percent of the Earth's land surface was buried under ice. Today, drumlin fields—such as those found at Múlajökull in Hofsjökull—are arrayed in fan-like distributions. By inspecting these patterns from the air, researchers can trace the previous extent and motion of glaciers that have long since vanished, revealing how the planet's surface was reshaped by moving ice.

The term itself is rooted in history, first appearing in 1833. It originates from the Gaelic word 'druim,' meaning a rounded hill or mound. Today, these features remain prominent in lowland regions where they provide a visual record of how massive continental ice sheets once dominated the globe.

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