Rock Columns
55.24094° N, -6.51176° E
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Rock columns are the result of cooling lava flows that create defined prismatic columns, in which the process is referred to as columnar jointing. The lava required to create columnar joints is basaltic lava and is a common type of melted rock that comes from volcanos in the form of magma and lava. To discuss the physical principles as to why the lava solidifies in these defined prismatic shapes it is important to note that once basaltic lava cools it contracts inwards. Once it contracts it creates internal stresses within the basalt and causes cracking to occur. Ideally, the basalt would contract inwards and create round fractures but since there is no room between the fractures the basalt is forced to cool in a hexagonal pattern to fill in these openings, which in turn causes planar fractures between basalt surfaces.
This image displays the pattern that occurs once basaltic lava cools, creating columnar joints with no space between them
This is a commonly occurring process in nature and columnar joints can even be found naturally in dry muddy areas (mud cracks) or from dried corn starch. Additionally, there are some popular landmarks where columnar joints can be observed worldwide, including The Giant’s causeway (Northern Ireland), The Devil’s Post pile (California, U.S.), or Fingal’s Cave (Staffa Island, Scottland).
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Both images show additional examples of columnar jointing occuring naturally in nature. One image displays dried starch, while the other is displaying mud cracks in a dry soil.