Oceanic islands preferred thin crust

Sep 17, 2012
Oceanic islands preferred thin crust
Credit: http://www.flickr.com/photos/gsfc/6630087415/

(Phys.org)—Debate over how and where oceanic island chains, like Hawaii, form, is at an end according to an academic from The Australian National University.

Dr Oliver Nebel from the Research School of , in the ANU College of Physical and , has been involved in a world-wide collaboration which sheds new light on the processes behind the formation of island chains. His findings are published in Nature Geoscience today.

"For a long time many have argued that some volcanic island chains, such as the Hawaiian Emperor Chain, are formed from things called hotspots. These hotspots come from the very deep interior of the Earth, where hot material rises in so-called ," said Dr Nebel.

"These mantle plumes burn through the crust and erupt at the surface. As these hotspots are stationary, with the plates moving on top of them, they leave a track, creating chains.

"This theory poses some problems though, because if you look at , some have tracks, and others have none. Some are disturbed in their tracks: they appear somewhere and then they just vanish."

The international research team analysed taken from a range of hotspots in the South Atlantic Ocean. Their research found that it was the nature of the crust that was causing these oddities.

"We showed that the thickness of crust has a major effect on whether these mantle plumes can burst through," said Dr Nebel.

"For example, if you put a candle underneath cardboard and the cardboard is moving slowly enough, you can burn through it. But if you put a couple of pieces of on top of each other, the time may not be sufficient to burn through. Because the Earth's crust is very diverse there are parts where you can cut through and others not."

Dr Nebel said that he hopes his research solves the debate of the existence of plumes that lead to the formation of oceanic island chains.

"There has been a long debate about whether mantle plumes actually exist. Some use the disturbance in hotspot tracks as an argument against the existence of plumes," he said.

"What we found is that not only do these plumes exist, but the way they operate is quite complex. Both the crust and the source of the plumes are controlling the formation of islands. It's a more complex, diverse and dynamic system than we originally thought."

Explore further: Magnitude-7.2 earthquake shakes Mexican capital

Related Stories

Recommended for you

Magnitude-7.2 earthquake shakes Mexican capital

Apr 18, 2014

A powerful magnitude-7.2 earthquake shook central and southern Mexico on Friday, sending panicked people into the streets. Some walls cracked and fell, but there were no reports of major damage or casualties.

User comments : 0

More news stories

China says massive area of its soil polluted

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

UN weather agency warns of 'El Nino' this year

The UN weather agency Tuesday warned there was a good chance of an "El Nino" climate phenomenon in the Pacific Ocean this year, bringing droughts and heavy rainfall to the rest of the world.

Making graphene in your kitchen

Graphene has been touted as a wonder material—the world's thinnest substance, but super-strong. Now scientists say it is so easy to make you could produce some in your kitchen.