Thursday, August 23, 2007 | Science : Earth Sciences | print version

Diamonds unlock secrets of early Earth

by Reuters, CNN

Reposted from:
http://www.cnn.com/2007/TECH/science/08/23/earth.diamonds.reut/index.html

STORY HIGHLIGHTS
- Diamonds more than 4 billion years old discovered in Western Australia
- The diamonds are the oldest identified fragments of the Earth's crust
- The gems suggest the Earth may have cooled faster than previously thought

diamond

LONDON, England (Reuters) -- Diamonds more than 4 billion years old -- nearly as old as the Earth itself -- have been discovered in Western Australia, giving scientists vital clues about the early history of our planet.

Found trapped in zircon crystals in the Jack Hills region, the small gems are the oldest identified fragments of the Earth's crust and their existence suggests the Earth may have cooled faster than previously thought, experts said on Wednesday.

The time between the creation of the Earth around 4.5 billion years ago and the formation of the oldest known rocks some 500 million years later is known as the Hadean period -- the "dark ages" of geology.

Many geologists have traditionally thought of it as a time when the surface of the planet was a mass of molten lava. But the discovery of the ancient diamonds, reported in the journal Nature, challenges that view.

Martina Menneken of Westfalische Wilhelms-Universitat Muenster, Germany, and colleagues said the presence of diamonds -- which are created under intense pressure -- implied there was a relatively thick continental crust as early as 4.25 billion years ago.

This suggests it may have taken only around 200 million years for the Earth's surface to cool enough for water to condense and oceans to form.

"These latest findings indicate that the planet was already cooling and forming a crust much earlier than previously thought," Alexander Nemchin, an expert in geochemistry at Australia's Curtin University of Technology and one of Menneken's co-researchers, said in a statement.

"Jack Hills is the only place on Earth that can give us this kind of information about the formation of the Earth. We're dealing with the oldest material on the planet."

Radioactive dating showed the crystals from Western Australia varied in age from 3.06 billion to 4.25 billion years, making them almost 1 billion years older than the previous oldest-known diamonds.

Martin Van Kranendonk, a senior geologist with the Geological Survey of Western Australia, said unraveling the history of the crystals was a boon for researchers.

"Any information about the very early Earth is fantastic, it's like a Christmas present for geoscientists," he said.

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1. Comment #65264 by Scott McMeekin on August 23, 2007 at 11:51 am

Cool. I wonder how much more irrefutable evidence will be required until wingnuts stop claiming that the earth is circa 6000 years old.

Scott.

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2. Comment #65314 by pissinintothewind on August 23, 2007 at 2:56 pm

They were planted!

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3. Comment #65321 by Yorker on August 23, 2007 at 3:20 pm

Yes, definitley the work of Satan, all this radio-active dating nonsense, tut, tut!

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4. Comment #65324 by steveroot on August 23, 2007 at 3:33 pm

Praise the Cosmic Jeweler!
Steve

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5. Comment #65340 by BMMcArdle on August 23, 2007 at 5:22 pm

It's like a communion wafer for physicists!

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6. Comment #65343 by bluebird on August 23, 2007 at 5:36 pm

Square cut or pear shaped...

There's another article in recent 'Nature' http://www.nature.com/nature

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7. Comment #65361 by OkiMike on August 23, 2007 at 9:56 pm

Geoscientists don't have "Christmas". Only "Happy Holidays"...

;)

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8. Comment #65379 by nickthelight on August 24, 2007 at 1:35 am

It would seem that 'Diamonds are Forever'.

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9. Comment #65381 by scottishgeologist on August 24, 2007 at 1:50 am

The thing is, with every day that passes, every year that goes by, there is simply more and more evidence that supports the "old earth" idea. The science just keeps confirming what we already know.

Yet, these YEC types keep wanting to fly in the face of it. The absolutely outstanding example is Kurt Wise (who gets a comment thread all to himself in an article by Dawkins - need to read it again)

Wise: "Although there are scientific reasons for accepting a young earth, I am a young-age creationist because that is my understanding of the Scripture. As I shared with my professors years ago when I was in college, if all the evidence in the universe turns against creationism, I would be the first to admit it, but I would still be a creationist because that is what the Word of God seems to indicate. Here I must stand."

You cant fight against this sort of thing. Its impossible. Their minds are made up, the Bible says it, therefore, no other explanation is possible.

Note: "if all the evidence in the universe turns against creationism" With this diamonds research, we have simply yet another piece of evidence.

But of course, to the likes of Wise, despite an otherwise solid background in academia, this can be written off. Goddidit!

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10. Comment #65382 by Philip1978 on August 24, 2007 at 1:50 am

Yorker, this is not the work of Satan, don't be daft man...everybody knows its the Flying Spaghetti Monster that messes up the dating process!!

This is fascinating, I really enjoy hearing stories like this, it gives me hope when I hear scientists are doing something worthwhile and interesting instead of pratting around creating non existent gods. Bravo chaps, keep up the good work!

Philip

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11. Comment #65449 by Nebularry on August 24, 2007 at 8:28 am

Someone please comment. In your opinion, will this new discovery help explain the rapid appearance of life on earth? It would seem reasonable to me but I'd like a more knowledgeable opinion. Thanks!

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12. Comment #65479 by ignored_ethos2 on August 24, 2007 at 12:28 pm

I wonder what effect this will have on moon origin theories. Maybe collision theory dating is off or maybe earth actually cooled very quickly or?

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13. Comment #65908 by mumbles on August 27, 2007 at 10:09 am

" "Any information about the very early Earth is fantastic, it's like a Christmas present for geoscientists," he said. "

Anyone else crack up at this?

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14. Comment #86252 by bichard on November 8, 2007 at 8:43 pm

Well... just a bit of technical nit picking. Diamonds by definition are not "fragments of the earth's crust". The upper limit of the diamond phase stability field for carbon in temperature pressure space is 35,000 atmospheres more or less and would
probably have been even higher in the Hadean as it is plausible that the mantle would have been at higher temperatures. In present day terms that kind of pressure corresponds to a depth of about 150 km, far deeper than any present day crust.

Further while it is true that 4.0+ billion y.o. diamond is a new upper limit for terrestrial diamonds, 3.0+ ages have been known for some time.

By logic alone it is clear that eventually diamonds
as old as the earth itself might be found since all that is required for them to have formed is the right chemistry, and sufficient pressure. What is lacking in the article as reported is any evidence that these diamonds were erupted to the surface in the time range suggested. All diamonds are older than their age of eruption, usually much older.

I wasn't able to find the link in Nature because it was too general, perhaps the actual paper reporting these results provides evidence the diamonds were actually erupted in this time frame.

One more nitpick that troubles me, the article mentions the diamonds were included in zircons, this I find a bit of a stretch as zircon is a silicate mineral formed at low pressure and high temperature in an oxidizing environment. Diamonds oxidize readily at low pressure and high temperature unless the environment is highly reducing. Given that the source is CNN its certainly possible that the reporter juxtaposed the phase arrangement and that the zircons were included in the diamond. Also it is much easier to date zircon than diamond. But that then raises the question were the zircons dated instead of the diamond and if so, the diamond could have formed almost anytime after the zircons.

I find this article too simplified and confused to carry much credibility and a direct cite to the nature paper would have been much more meaningful I would hope.

To Nebularry - IMO no it wouldn't. Given the energetic state of the early earth, it would not be at all surprising if "crustal type rocks" were formed very early in its history. More important would be the presence of liquid water.

Sorry to be so late in replying but until recently I have not been able to post comments due to a browser glitch which the maintainers have fixed I am pleased to note.

Cheers all -

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15. Comment #193762 by rod-the-farmer on June 16, 2008 at 2:48 am

I happened upon this clip

http://www.youtube.com/watch?v=TL_MtKNZdsI&NR=1

and wondered if there is anything available to counter the assertion that these radiohaloes "prove" the earth is very young ?

EDIT

OK, I found this after some googling.

http://gondwanaresearch.com/rate.htm

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16. Comment #195434 by TeraBrat on June 18, 2008 at 8:12 am

Diamonds are compressed carbon. Carbon 14, the radioactive isotope of carbon has a half life of 5730 years. Carbon is usually used to date things up to about 30,000 possibly 40,000 years. Older fossils are dated using longer lived radioactive isotopes like argon.

I'm wondering what radioactive isotopes they used to date these diamonds as 4,000,000,000 years old. It seems highly unlikely that it could have been carbon.

Anyone know what the peer review paper this article is based on is? I'd like to see how they did this.

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17. Comment #195457 by black wolf on June 18, 2008 at 8:53 am