Starkrusher
Basalt columns
The yellow is caused by lichens growing on the surface of these columns.
FROM WIKIPEDIA:
During the cooling of a thick lava flow, contractional joints or fractures form (in basalt). If a flow cools relatively rapidly, significant contraction forces build up.
While a flow can shrink in the vertical dimension without fracturing, it can't easily accommodate shrinking in the horizontal direction unless cracks form; the extensive fracture network that develops results in the formation of columns.
The topology of the lateral shapes of these columns can broadly be classed as a random cellular network. These structures are predominantly hexagonal in cross-section, but polygons with three to twelve or more sides can be observed.
The size of the columns depends loosely on the rate of cooling; very rapid cooling may result in very small (<1 cm diameter) columns, while slow cooling is more likely to produce large columns.
Basalt columns
The yellow is caused by lichens growing on the surface of these columns.
FROM WIKIPEDIA:
During the cooling of a thick lava flow, contractional joints or fractures form (in basalt). If a flow cools relatively rapidly, significant contraction forces build up.
While a flow can shrink in the vertical dimension without fracturing, it can't easily accommodate shrinking in the horizontal direction unless cracks form; the extensive fracture network that develops results in the formation of columns.
The topology of the lateral shapes of these columns can broadly be classed as a random cellular network. These structures are predominantly hexagonal in cross-section, but polygons with three to twelve or more sides can be observed.
The size of the columns depends loosely on the rate of cooling; very rapid cooling may result in very small (<1 cm diameter) columns, while slow cooling is more likely to produce large columns.