Fingal’s Cave Basalt Columns — Staffa, Scotland
The iconic basalt columns of Fingal’s Cave are the result of flood basalt volcanism associated with the opening of the North Atlantic Ocean during the Paleocene. This event was driven by the early stages of continental rifting between what is now Europe and North America.
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| Basalt columns near Fingal’s Cave. Photo : © Jim Richardson |
When basaltic lava erupted and spread across the region, it cooled relatively slowly. This slow cooling caused the lava to contract and fracture, forming the characteristic columnar jointing — hexagonal columns, often vertical, and strikingly regular.
These columns are part of the same igneous province as the Giant’s Causeway in Northern Ireland, to which they are geologically and petrologically identical. Both sites belong to the North Atlantic Igneous Province (NAIP) — one of Earth’s largest known volcanic provinces.
Rock Type
- Name: Tholeiitic basalt
- Texture: Fine-grained, often vesicular at upper levels
- Mineralogy: Primarily plagioclase, pyroxene, and olivine; minor magnetite
- Structures: Columnar jointing, pillow basalts in marine sections, flow banding in some locales
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