Showing posts with label depths. Show all posts
Showing posts with label depths. Show all posts

Thursday, January 12, 2017

Big Diamonds From Great Depths and how do Gemstones Form: The most valuable jewelry offers researchers important information from the depths of the Earth

Geologists studied these scraps of diamond leftover from the shaping of big jewels. Evan Smith/Gemological Institute of America
Evan Smith wanted to get his hands on the world's biggest diamonds — the kind that sit at royal scepters, and the ones that are always the target of elaborate movie heists.

But this wasn't for some nefarious get-rich-quick scheme. It was for science.

"The most valuable, the most prized, of all gemstones are coincidentally some of the most scientifically valuable pieces of the Earth," says Smith, a diamond geologist at the Gemological Institute of America.


The Ungraspable Value of the World's Largest Diamond The New Yorker

They're scientifically valuable because they come from a deep part of the Earth that humans can't access and don't know that much about.




GEMSTONE TREASURES OF THE WORLD POSTER  Jewelry auction Pinterest

Because of their rare size and quality, Smith thought these diamonds might have come from somewhere different, though no one knew exactly where.

"It was a total mystery," says Smith.


Layers of the Earth - Maggie's Science Connection

To solve that mystery, he'd have to look inside the diamonds, at tiny specs of junk no wider than a human hair that the crystals had brought with them on their journey from the deep.


"You really couldn't ask for a better vessel to store something in. Diamond is the ultimate Tupperware," says Smith.


World's Largest Rough Diamond Fails to Sell At Auction Forbes

A slogan like "the ultimate Tupperware" won't sell many engagement rings, but for scientists, the diamonds' Tupperware-quality is key. It makes the geologic equivalent of messages in a bottle.


But Smith couldn't just knock on a royal palace door and ask to crack open the crown jewels.


Price and Buying Guide for 4 Carat Diamonds

Evan Smith

Gemological Institute of America

Instead, he got the Gemological Institute of America to buy eight fingernail-sized chunks of those big diamonds, the scraps leftover from when the rough diamonds were cut into sparkly jewels.


Earth structure infographic Freepik

After grinding some down and cutting others open, Smith used fancy techniques involving big microscopes, lasers and electron beams to figure what was inside. He also used some not-so-fancy equipment — a magnet attached to a string — to figure out if they contained iron. ("After staring at these inclusions for hours on end over the course of many months, you start to resort to some alternative tools," he says).



Diamond Cutting Green Laser Machine Diamond Industry

Smith eventually found that many of the stones contained bits of garnet with a silicon content indicating that they must have formed under very high pressure. He also found iron and nickel, shrouded in invisible envelopes of fluid methane.

"That's unusual. This is the first time I've seen methane around an inclusion," he says.


When he took a nondestructive look at 53 other diamonds passing through the institute for quality grading, he found that 38 of them contained the same unusual materials.

As Smith and his colleagues wrote Thursday in the journal Science, those odd bits and pieces told him two important things.


How Do Gemstones Form? Gem Rock Auctions

"One, they tell us that these large, exceptional-quality diamonds originate from extreme depths in the Earth," he says, from about 200 to 500 miles below us.


That's about as far under our feet as the International Space Station is above our heads. And it's about twice as deep as where most diamonds are born.

"So, that in itself is pretty amazing," says Smith.


The second thing he learned is that the diamonds had formed inside oxygen-deprived patches of liquid metal. And that's the first hard evidence that the Earth's mantle is not a uniform stew of oxygen-rich rocks



World's First Realization of Ultrahigh Pressure and Ultrahigh Temperature at the Earth's Center - Finally reaching the Earth's Core — SPring-8 Web Site

It might not sound very exciting, says Kanani Lee, a mineral physicist at Yale University, but it is.

"It further complicates things, but it makes us have to think more deeply about what's going on in the planet because ultimately this does affect what we see up on the surface," says Lee.

As the Earth cooled over the last 4.5 billion years, its layers slowly revolved from the core to the surface and back again. Until recently, scientists expected that the mantle, the part of the planet between the continental plates and its core, would be pretty thoroughly mixed, with oxygen distributed throughout. But these diamonds show that until relatively recently, there were pockets that somehow managed to resist that mixing.


A rare diamond carried this tiny package of material from hundreds of miles underground. It's about as wide as a poppy seed. Evan Smith/Gemological Institute of America


And those pockets were long-lasting and widespread enough to produce diamonds that surfaced on multiple continents and that range in age from about 100 million years old to about a billion years old.

It's unclear if those pockets are still around now. Nevertheless, it means that the planet and its past could be a little messier than scientists first thought.

"It tells you that we have to refine our thinking about how the planet – whether it's Earth or any other planet — evolves with time. And that our simple pictures may not be good enough anymore if we can't explain these features," says Lee.

Those odd features are just slivers of a much larger picture — how Earth became what it is today, including its ability to host life.


"Over time, those are the things that shape the surface of the Earth. They're the materials that the whole surface of the Earth is built with," Smith says.



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The above post is reprinted from materials provided by Npr. Note: Materials may be edited for content and length.

Wednesday, December 21, 2016

Rare Ghost Shark was filmed for the first time in Gulf of California - PHOTO, VIDEO

It looks like something out of a horror movie, with two dead eyes peering out of a pale patchwork of flesh, but that's a perfectly happy 'ghost shark' - otherwise known as a spookfish - cruising about in the deep sea off the coast of California.

The species, which features retractable sex organs on its forehead, has never been seen on film before.

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The individual has been identified by researchers at the Monterey Bay Aquarium Research Institute (MBARI) as Hydrolagus cf. trolli - known commonly as the pointy-nosed blue chimaera.


Chimaeras: Strange Fish With a Cartilaginous Skeleton Owlcation

The "cf." in its species name indicates that its physical characteristics closely match the official species description for Hydrolagus trolli, but without DNA evidence, they can't be sure.



In fact, there's also the possibility that this isn't just the first ever footage of a live Hydrolagus trolli - it could be showing us an entirely new species of ghost shark.

But because these fish are usually too large, fast, and agile to be caught by deep-sea roving vehicles, it's going to be incredibly difficult to find out for sure.

"If and when the researchers can get their hands on one of these fish, they will be able to make detailed measurements of its fins and other body parts and perform DNA analysis on its tissue,"

"This would allow them to either remove the cf. from their species description, or assign the fish to a new species altogether."

The footage was captured by an autonomous rover in the Gulf of California back in 2009, and researchers have only just released it to the public.

The creature is a chimera - an order of deep-sea fish that split off from sharks in the evolutionary tree nearly 400 million years ago, and has remained isolated ever since.

Chimaeras live on the ocean floor at depths of up to 2,600 metres (8,500 ft), and they have a permanent set of 'tooth plates' to grind their prey into pieces, unlike the conveyer belt of replaceable teeth found in sharks.


But perhaps their most creepy characteristic are the deep grooves cut into their flesh that make them look like something a serial killer stitched together:


Photo: MBARI
Until now, the pointy-nosed blue chimaera has only ever been identified in the southwestern Pacific Ocean, particularly around Australia, New Zealand, and New Caledonia, from specimens dredged up in fishing nets.

This new footage now suggests that the species has a much wider range than anyone had expected, and hints that it could range even further away from its known haunts have made researchers hopeful that it's not rare - just good at hiding.

In reality, those grooves are called lateral line canals, and they form a system of open channels on the heads and faces of ghost sharks.

They're thought to contain sensory cells that help these creatures detect movement in the pitch-black water.


You can see another view of them here, including the rows of dots that are also thought to be tiny sensory organs:


Photo: MBARI


"Similar looking, but as yet unidentified, ghost sharks have also been seen off the coasts of South America and Southern Africa, as well as in the Indian Ocean," Fulton-Bennett reports.

"If these animals turn out to be the same species as the ghost sharks recently identified off California, it will be further evidence that, like many deep-sea animals, the pointy-nosed blue chimaera can really get around."

The sighting has been described in Marine Biodiversity Letters


You can see more footage of a ghost shark below - this species has a distinctive purple hue, and a serious parasite problem:




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The above post is reprinted from materials provided by Sciencealert . Note: Materials may be edited for content and length.