Extreme Geology: The Giant’s Causeway, Ireland and Staffa, Scotland
→ Credit for photos: one, two, and three.These amazing basalt columns cane be found on Staffa, Scotland, and Giant’s Causeway in Nothern Ireland. These geological structures formed from volcanic activity over 50 mya where the slow cooling of basalt creates the hexagonal columns you see today. The process which creates such stunning hexagonal columns is called “columnar jointing”; a process where the basalt rapidly cools from the outside towards the centre, causing it to contract and form these structures.
(via geologyrocks)
Some interesting non-vertical basalt in Alcantara Gorges, Sicily.
Svartifoss
Iceland’s geology is dominated by volcanic activity. Many lava flows have cooled into columnar basalt outcrops, some of which can be accessed easily from roads and pathways. These basalts often form ledges over which glacier-fed streams flow, creating plunge pools and undercuts. Both these conditions are displayed at the Svartifoss, “foss” meaning “waterfall,” near the Visitor Centre of Skaftafell National Park in southern Iceland. The undercutting as shown in this unusual view reveals some of the “suspended” basalt columns.
Source: http://epod.usra.edu/blog/2003/09/svartifoss.html
(Source: 7geo, via geologyrocks)
Columnar Basalt: When a thick lava flow cools it contracts vertically but cracks perpendicular to its directional flow with remarkable geometric regularity – in most cases forming a regular grid of remarkable hexagonal extrusions that almost appear to be made by man. One of the most famous such examples is the Giant’s Causeway on the coast of Ireland (shown above) though the largest and most widely recognized would be Devil’s Tower in Wyoming . Basalt also forms different but equally fascinating ways when eruptions are exposed to air or water.
(via geologyrocks)
