DescriptionBasalt Rock Formation - geograph.org.uk - 180882.jpg
English: Basalt Rock Formation, in the Mull Lava Group of Palaeocene age. Taken on the way to the fossilised tree. I am indebted to Keith Burns for this explanation of the fascinating geological processes involved here :
"On the beach, basalt columns radiate from a central point on the
shore near the fossil tree. The columns are formed due to the cooling
effect of a standing tree on the lava flowing around the tree trunk.
The tree draws heat from the lava. When the lava shrinks, it forms
hexagonal shrinkage cracks which form columns whose axes are parallel to the
direction of heat flow. So the hexagonal columns radiate from the tree
trunk which is drawing heat from the lava.
If lava is in a level slab losing heat to the air above it, it cools from
the top down and forms the more familiar vertical hexagonal columns (e.g.
Giant's Causeway, Staffa, Sampson's Ribs on Arthur's Seat in Edinburgh).
There must have been a forest that was engulfed by the slowly flowing lava."
This example of columnar basalt is located on the coast of the island of Mull, Scotland.
This image was taken from the Geograph project collection. See this photograph's page on the Geograph website for the photographer's contact details. The copyright on this image is owned by Mick Garratt and is licensed for reuse under the Creative Commons Attribution-ShareAlike 2.0 license.
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== {{int:filedesc}} == {{Information |description={{en|1=Basalt Rock Formation. Taken on the way to the fossilised tree. I am indebted to Keith Burns for this explanation of the fascinating geological processes involved here :
"On the beach, basalt col