Salty water and gas sucked into Earth interior helps unravel planetary evolution

Sep 26, 2011

An international team of scientists has provided new insights into the processes behind the evolution of the planet by demonstrating how salty water and gases transfer from the atmosphere into the Earth’s interior.

The paper was published in Nature Geoscience today.

Scientists have long argued about how the Earth evolved from a primitive state in which it was covered by an ocean of molten rock, into the planet we live on today with a solid crust made of moving tectonic plates, oceans and an atmosphere.  

Lead author Dr Mark Kendrick from the University of Melbourne’s School of Earth Sciences said inert gases trapped inside the Earth’s interior provide important clues into the processes responsible for the birth of our planet and the subsequent evolution of its oceans and .
“Our findings throw into uncertainty a recent conclusion that gases throughout the Earth were solely delivered by meteorites crashing into the planet,” he said.

The study shows atmospheric gases are mixed into the mantle, inside the Earth’s interior, during the process called ‘subduction’, when tectonic plates collide and submerge beneath volcanoes in subduction zones. 

“This finding is important because it was previously believed that inert gases inside the Earth had primordial origins and were trapped during the formation of the ,” Dr Kendrick said.

Because the composition of neon in the Earth’s mantle is very similar to that in meteorites, it was recently suggested by scientists that most of the Earth’s gases were delivered by meteorites during a late meteorite bombardment that also generated visible craters on the Earth’s moon.
“Our study suggests a more complex history in which gases were also dissolved into the Earth while it was still covered by a molten layer, during the birth of the solar system,” he said.

It was previously assumed that gases could not sink with plates in tectonic subduction zones but escaped during eruption of overlying volcanoes.

“The new study shows this is not entirely true and the gases released from Earth’s interior have not faithfully preserved the fingerprint of solar system formation.” 

To undergo the study researchers collected serpentinite rocks from mountain belts in Italy and Spain. These rocks originally formed on the seafloor and were partially subducted into the Earth’s interior before they were uplifted into their present positions by collision of the European and African plates. 

“The serpentinite rocks are special because they trap large amounts of seawater in their crystal structure and can be transported to great depths in the ’s mantle by subduction,” he said.

By analysing the inert gases and halogens trapped in these rocks, the team was able to show gases are incompletely removed by the mineral transformations that affect serpentinites during the subduction process and hence provide new insights into the role of these trapped in the evolution of the planet. 

Explore further: Magnitude-7.2 earthquake shakes Mexican capital

Related Stories

Earth's crust moves like a yo-yo: research

Apr 11, 2011

(PhysOrg.com) -- New research from The Australian National University has shed light on the secrets of the deep Earth and will lead to better understanding of important geological processes.

Clues included in diamonds

Oct 07, 2010

A study of Brazilian diamonds by Earth scientists from the University of Bristol has found that tiny inclusions in the diamonds contain traces of oceanic crust and sedimentary rocks, formed originally on the ...

Plate tectonics may take a break

Jan 03, 2008

Plate tectonics, the geologic process responsible for creating the Earth’s continents, mountain ranges, and ocean basins, may be an on-again, off-again affair. Scientists have assumed that the shifting of crustal plates ...

Earth's atmosphere came from outer space, find scientists

Dec 10, 2009

(PhysOrg.com) -- The gases which formed the Earth's atmosphere - and probably its oceans - did not come from inside the Earth but from outer space, according to a study by University of Manchester and University ...

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 : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Yellowdart
not rated yet Sep 26, 2011
Hydroplate Theory fits this a lot better than this lousy subduction explanation.

Late meteorites are from Earth, which is why they mimick earth in contents.

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.