Tor (rock formation)
A tor is a large, free-standing rock outcrop that rises abruptly from the surrounding smooth and gentle slopes of a hill. Tors are most commonly formed from granite or other igneous rocks, but can also develop in sedimentary rocks like sandstone.
The formation of tors is a complex process involving multiple stages of weathering and erosion. The prevailing theory suggests that tors are formed in two main phases:
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Deep Weathering: During a period of warmer, wetter climate conditions, chemical weathering penetrates deep along joints and fractures in the bedrock. This process, often occurring beneath a surface layer of soil or sediment, selectively decomposes the rock, leaving behind corestones of relatively unweathered material.
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Erosion and Exposure: As the climate changes and erosion processes become more dominant, the overlying soil or sediment is stripped away. This exposes the weathered rock and corestones. The weathered material is easily removed, while the more resistant corestones remain as prominent features on the landscape. Subsequent weathering and erosion further sculpt these corestones into the characteristic shapes of tors.
Tors can take on a variety of forms, ranging from isolated stacks of rock to clusters of boulders. They are often characterized by rounded shapes, sharp edges, and prominent joints. The size of tors can vary significantly, from a few meters in height to several tens of meters.
Tors are found in many parts of the world, particularly in areas with granite bedrock and a history of fluctuating climate conditions. Notable regions include Dartmoor and Bodmin Moor in England, Brittany in France, and parts of the Appalachian Mountains in North America.
The presence of tors can significantly impact local ecosystems, providing habitat for specialized plants and animals. They also contribute to the aesthetic value of landscapes and are often popular tourist destinations.