Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stress relief caused Giant’s Causeway

28.01.2002


Ireland’s huge hexagonal columns are a natural consequence of lava cooling.


The Giant’s Causeway.
© Allan Davies / LGPL



The Giant’s Causeway is not the work of men or monsters, but a natural consequence of how lava cools and solidifies, new computer simulations suggest.

The causeway is a field of roughly hexagonal basalt columns up to 40 feet high on the shores of County Antrim in Northern Ireland. It arose when a flow of volcanic rock split into hexagonal columns to relieve stress, according to Eduardo Jagla of the Centro Atómico Bariloche in Argentina and Alberto Rojo of the University of Michigan in Ann Arbor1.


Viscous lava shrinks as it cools, so rock in a solidifying layer is pulled in all directions at once, the researchers explain. This sets up stresses like those that make paint crack or wrinkle. As this stress increases, cracks appear.

As the causeway’s 40,000 pillars formed, cracks in the solid layer above would have propagated down into the solidifying layer below, like a stack of paint layers drying one after another. These cracks would have been deflected along the way onto new courses that provided the greatest stress relief.

Cracks that form a hexagonal network reduce energy more effectively than randomly orientated cracks, say Jagla and Rojo.

If this idea is correct, the causeway’s hexagonal columns were created by a much more random vertical-cracking structure, which once stood over the columns but has since been eroded by wind, rain and sea. There is geological evidence that the causeway we see today is merely a part of an original solidified lava field.

They might be giants

When the Giant’s Causeway was first reported to the Royal Society in London in 1693, some wondered whether men had created the step-like stone columns with picks and chisels. Local legend attributes them to the Irish giant Finn McCool, said to have wanted to walk to Scotland without wetting his feet. The more prosaic lava-flow explanation was put forward in 1771.

The columns form a natural stairway from a cliff into the sea. All have between four and eight sides, but most are roughly hexagonal. This geometric regularity has perplexed scientists for centuries.

Jagla and Rojo support their idea with computer simulations of fracture patterns in a layer of particles joined by springs, which mimic the mutually attractive atoms in the rock. The researchers simulate shrinking and cracking in a series of particle layers, using the final cracking pattern in one layer as the starting point for the cracking of the layer below.

They find that the pattern evolves from one that has many randomly distributed cracks to one in which the fractures define large polygons, most of which are six-sided.

What’s more, the model correctly predicts the proportions of columns with different numbers of sides and the average cross-sectional areas of these columns.


References

  1. Jagla, E. A., Rojo, A. G. Sequential fragmentation: the origin of columnar quasihexagonal patterns. Physical Review E, 65, 026203, (2002).


PHILIP BALL | © Nature News Service
Further information:
http://www.nature.com/nsu/020121/020121-15.html

More articles from Earth Sciences:

nachricht Cause for variability in Arctic sea ice clarified
14.05.2019 | Max-Planck-Institut für Meteorologie

nachricht Arctic rivers provide fingerprint of carbon release from thawing permafrost
08.05.2019 | Stockholm University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Self-repairing batteries

UTokyo engineers develop a way to create high-capacity long-life batteries

Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...

Im Focus: Quantum Cloud Computing with Self-Check

With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.

Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...

Im Focus: Accelerating quantum technologies with materials processing at the atomic scale

'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.

However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...

Im Focus: A step towards probabilistic computing

Working group led by physicist Professor Ulrich Nowak at the University of Konstanz, in collaboration with a team of physicists from Johannes Gutenberg University Mainz, demonstrates how skyrmions can be used for the computer concepts of the future

When it comes to performing a calculation destined to arrive at an exact result, humans are hopelessly inferior to the computer. In other areas, humans are...

Im Focus: Recording embryonic development

Scientists develop a molecular recording tool that enables in vivo lineage tracing of embryonic cells

The beginning of new life starts with a fascinating process: A single cell gives rise to progenitor cells that eventually differentiate into the three germ...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Cement as a climate killer: Using industrial residues to produce carbon neutral alternatives

20.05.2019 | Materials Sciences

When bees are freezing

20.05.2019 | Life Sciences

Machine learning speeds modeling of experiments aimed at capturing fusion energy on Earth

20.05.2019 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>