Lightning can shape MOUNTAINS: African peaks were formed by strikes capable of blowing 10 metres of rock into the air

  • Previous theories claim mountains break down over thousands of years
  • This is said to be due to temperature changes in the mountainous rock
  • Scientists now believe mountains in Africa were shaped by lightning
  • They proved their theory by monitoring changes on a compass needle
  • Areas where a lightning struck caused the needle to swing 360 degrees
  • This suggests the mountains evolved 'very quickly and very dramatically'

By Ellie Zolfagharifard

PUBLISHED: 06:35 EST, 6 January 2014 | UPDATED: 06:43 EST, 6 January 2014

Lighting storms are impressive displays of nature's power - but up until now scientists hadn’t realised that they could also sculpt mountains.

A team of researchers from Johannesburg recently discovered that a single lightning bolt could, for example, blow three to 10 cubic metres (100 to 350 cubic feet) out of bedrock.

This goes against the current assumptions that the peaks above 3,050 metres (10,000ft) tend to break down over hundreds of thousands of years.

Lighting storms are impressive displays of nature's power - but up until now scientists hadn't realised that they could also sculpt mountains

Lighting storms are impressive displays of nature's power - but up until now scientists hadn't realised that they could also sculpt mountains

The discovery was made by Professor Stefan Grab while studying the Drakensberg mountains in Lesotho, southern Africa.

Previous theories claim that water melting and freezing inside cracks causes the rocks on mountains to break into pieces as they expand and break off. 

 

More...

The Wind River Range, the Sierra Nevada and the Rocky Mountains were thought to have been shaped in this way, for example.

But unlike these formations, Professor Grab believes that lightning was the main cause behind the creation of the mountain landscapes in southern Africa

In Lesotho's Drakensberg mountains, for instance, the team found that a single lightning bolt could blow three to 10 cubic metres (100 to 350 cubic feet) out of bedrock

In Lesotho's Drakensberg mountains, for instance, the team found that a single lightning bolt could blow three to 10 cubic metres (100 to 350 cubic feet) out of bedrock

New research done on the Drakensberg mountains in South Africa debunks previous suggestions that cold temperatures played a dominate role in mountain formation

New research done on the Drakensberg mountains in South Africa debunks previous suggestions that cold temperatures played a dominate role in mountain formation

HOW CAN LIGHTNING SCULPT MOUNTAINS?

Lightning

The hit: Lighning strickes the rock surface. The heat - which is around 27760 ºC - vapourises water that is stored in the cracks.

The explosion: The force of the vapourised water explosed the rocke, moving 10 tonnes of debris as far as 10 metres (30 feet) away. New cracks help to continue the process of weathering.

In Lesotho's Drakensberg mountains, for instance, the team found that a single lightning bolt could blow three to 10 cubic metres (100 to 350 cubic feet) out of bedrock.

This goes against the current assumptions that the peaks above 3,050 metres (10,000 feet) tend to break down over hundreds of thousands of years.

His team used a compass to prove their theory. ‘A compass needle always points to magnetic north,’ said Professor Grab's colleague Professor Jasper Knight. 

‘But when you pass a compass over a land’s surface, if the minerals in the rock have a strong enough magnetic field, the compass will read the magnetic field of the rock, which corresponds to when it was formed.

‘In the Drakensburg, there are a lot of basalt rocks which contain a lot of magnetic minerals, so they’ve got a very strong magnetic signal.’

If a compass is passed over an area where a lightning strike occurred, its needle will suddenly swing through 360 degrees.

‘The energy of the lightning hitting the land’s surface can, for a short time, partially melt the rock and when the rock cools down again,’ added

‘It takes on the magnetic imprint of today’s magnetic field, not the magnetic field of millions of years ago when the rock was originally formed.’

Because of the movement of continents, magnetic north for the newly formed rock will be different from that of the older rock around it.

Professor Knight and Professor Grab mapped out the distribution of lightning strikes in the Drakensburg and discovered that lightning significantly controls the evolution of the mountain landscapes because it helps to shape the summit areas with this blasting effect.

Previously, angular debris was assumed to have been created by changes typical of cold, glacial environments, such as fracturing due to frost.

Water enters cracks in rocks and when it freezes, it expands, causing the rocks to split apart.

‘Many people have considered mountains to be pretty passive agents, just sitting there to be affected by cold climates over these long periods of time,’ said Professor Knight.

‘This evidence suggests that that is completely wrong. African mountain landscapes sometimes evolve very quickly and very dramatically over short periods of time. These are actually very sensitive environments and we need to know more about them.’

Previously, angular debris was assumed to have been created by changes typical of cold, glacial environments, such as fracturing due to frost

Previously, angular debris was assumed to have been created by changes typical of cold, glacial environments, such as fracturing due to frost

The research team also attempted to quantify how much debris was moved by such blasts, which can cause boulders weighing several tonnes to move tens of metres.

The stability of the land’s surface has important implications for the people living near the mountains. ‘If we have lots of debris being generated it’s going to flow down slope and this is associated with hazards such as landslides,’ said Professor Knight.

Mountains are also inextricably linked to food security and water supply. In Lesotho, a country crucial to South Africa’s water supply, food shortages are leading to overgrazing, exposing the rock surface and making mountain landscapes even more vulnerable to weathering by lightning.

Professor Knight hopes the research will help to put in place monitoring and mitigation to try and counteract some of the effects.

‘The more we increase our understanding, the more we are able to do something about it,’ he said.


 

Comments (11)

Share what you think

 View all

The comments below have not been moderated.

This type of article is a good example of the poor science journalism in the DM. The journalist picks one small piece of research (from among thousands on the same subject) and declares it to be the new authority. Readers then wonder why 'science' changes its mind in the future when another article tells the opposite story. Meanwhile, the science community doesn't change its mind like the wind. It requires very strong peer reviewed evidence before considering a new theory, and then it requires other research performed by unrelated groups of scientists to support the theory. Eventually, when the weight of evidence tips in favour of the new theory, then that new theory is accepted and becomes scientific consensus. There may be something in this particular research, but it is unlikely to replace weathering as the major cause of mountain erosion. It is probably just an additional cause.

4
20
 Click to rate

The DM is increasingly including an odd selection of articles based on quite speculative or perceptibly trivial scientific findings, along with a heavy dose of irrelevant christian references in its science article headlines. The DM is also a fan of incorrectly claiming that scientists are 'baffled' or rather fickle about scientific theories. One could almost imagine that this is a subtle ongoing campaign to discredit science in the eyes of its readership. This may suit its oddly obsessive campaigns regarding all things religious and all things climate change related. Who knows what goes on in the minds of DM journalists?

1
12
 Click to rate

In DM land, 'facts' and 'truth' are not things to be decided by scientific method or rational inquiry. Instead, they derive from the 'gut instincts' or 'moral compass' of 'right thinking people'. The DM cannot bear the idea that science can prove them wrong. Therefore, DM journalists seek to discredit science by trivialising it. It is part of their anti-intellectualisation agenda - just look at the right hand side of the page to see what they want from their readers: stupefied ignorance.

0
1
 Click to rate

And WHO mad the Lightning? I KNOW who made the mountains > BEWEAR

15
1
 Click to rate

I think it's time you spoke to your doctor again, Big Nugget. You need stronger pills.

1
11
 Click to rate

Are you saying that BEWEAR made the mountains?

0
7
 Click to rate

Makes sense why Table Mountain in Cape Town is flat. Lightning sliced off it's peaks. Duh!!

8
7
 Click to rate

That's how m onkey was born from his stone egg.....wasn't it?

4
5
 Click to rate

It wasn't lightning strikes, it was the storm giants, I saw them in the Hobbit film. Duh!

4
17
 Click to rate

and ice cream caused the sand to develop on beaches

11
7
 Click to rate

Should have been brainless barry imo

8
10
 Click to rate

The views expressed in the contents above are those of our users and do not necessarily reflect the views of MailOnline.

Add your comment

By posting your comment you agree to our house rules.

Who is this week's top commenter? Find out now