By Bethany Smith
Updated Aug 30, 2022
Weathering and erosion are the twin engines that sculpt Earth’s surface. While weathering breaks down rocks and structures, erosion transports the resulting fragments to new locations. Understanding their distinct roles—and how they interact—helps explain the formation of valleys, dunes, caves, and more.
Both processes act as agents of change, wearing away rock through removal of material. Water, wind, and other natural forces drive both weathering and erosion, making them inseparable in many landscapes.
When chemical bonds within rocks are broken by reactions with water, oxygen, or other elements, the result is a softer, more fragile structure. This process, often triggered by oxidation or hydrolysis, leads to the release of sediment that can later be moved by erosion.
Physical forces, such as freezing water or tectonic shifts, crack rocks without chemical change. Common drivers include frost heave, earthquakes, and temperature fluctuations that create pressure within the rock, prompting pieces to separate.
Living organisms—plants, animals, fungi, or bacteria—can alter rock through growth or chemical reactions. Roots, for example, exert pressure that loosens soil or rock, a process that can accelerate chemical weathering and, over time, become a primary force in landscape evolution.
Once weathering removes material, erosion takes over to transport the detritus. Gravity is the main driver, but wind, water, and ice also play critical roles in relocating sediment. Erosion determines the final placement of eroded material, completing the cycle of landscape transformation.
