Submerged Mass: Under the water, there is granite undersea

May 23, 2013 8:09 AM

Scientists have discovered a 10-metre-high rock of granite deep in the Atlantic, more than 8,000 feet beneath the sea in a region known as the Rio Grande Elevation (Google auto-translation; original Portuguese webpage). It is believed that this formation could be part of a lost continent, something formed when South America split from Africa, around 100 million years ago.

The formation was found by an Japan Agency for Marine-Earth Science and Technology (JAMSTEC; mentioned previously) expedition, dubbed QUELLE2013. "Quelle" means "roots" or "origin" in German, and stands for "Quest for the Limit of Life." The project is a yearlong mission involves exploring hydrothermal vent fields, submarine seepage sites, deep-sea trenches and other extreme environments to explore the habitable limits of life and its unique survival strategies.

According to a JAMSTEC official, the finding was “not totally a coincidence.”

They had been aware that Brazilian scientists had collected what appeared to be granite in the area, but it remained a mystery whether the granite was intrinsic or whether it had been dropped by ships passing through, the official said.

Scientists plan to drill for more samples later this year, as further conformation is needed. Geology Service of Brazil (CPRM) geology director Roberto Ventura Santos said

If it is the case that we find a continent in the middle of the ocean, it will be a very big discovery that could have various implications in relation to the extension of the continental shelf.

As is the case with any mysterious, submerged "lost continent," (previously) talk of Atlantis gets bandied about. "We speak of Atlantis more in terms of symbolism," Santos noted. "Obviously, we don’t expect to find a lost city in the middle of the Atlantic."

posted by filthy light thief (43 comments total)

Dammit! Wrong part of the ocean for R'lyeh.
posted by Kitteh at 8:17 AM on May 23, 2013 [7 favorites]

I'm a little disappointed that it doesn't look like this.
posted by asnider at 8:23 AM on May 23, 2013 [2 favorites]

When searching for Atlantis you never, ever want to take anything for granite.
posted by Floydd at 8:26 AM on May 23, 2013 [35 favorites]

Nice one, Floydd.
posted by SixteenTons at 8:27 AM on May 23, 2013 [1 favorite]

Namor could not be reached for comment.
posted by Cool Papa Bell at 8:28 AM on May 23, 2013 [2 favorites]

I'm sure someone will want to mine it.
posted by michellenoel at 8:29 AM on May 23, 2013

"it remained a mystery whether the granite was intrinsic or whether it had been dropped by ships passing through, the official said."

WUT. Is this a thing?
posted by jmccw at 8:39 AM on May 23, 2013 [2 favorites]

"Obviously, we don’t expect to find a lost city in the middle of the Atlantic."

I guess they are already biased toward what they do expect to find and whatever doesn't fit their preconceived notions is going to be buried or ignored.
posted by Renoroc at 8:41 AM on May 23, 2013

Does this mean that kitchen countertops will get cheaper?
posted by njohnson23 at 8:41 AM on May 23, 2013 [2 favorites]

So which continent was it that didn't return their ex's stuff after the split?
I do hope they get back together again though. That Asia is no good for Africa.
posted by Kabanos at 8:44 AM on May 23, 2013 [1 favorite]

10 meters seems like a pretty small chunk of rock to cause people to say "continent". I'm betting it fell off a ship.
posted by mathowie at 8:50 AM on May 23, 2013 [2 favorites]

WUT. Is this a thing?

Ballast stones

Also, that is how we get our countertops.
posted by Sys Rq at 8:51 AM on May 23, 2013

I find this very odd and somewhat questionable. It appears that the evidence they have is video? Yeah, call me when you have an actual core.

Short version: Generally speaking many of the oceans have been formed as continents move apart due to sea floor spreading. Rocks formed at the ridges where spreading occurs are mafic rocks containing dark, heavy minerals that have come up from deep in the earth. There is a pretty specific way this happens - ophiolite complexes/sequences. Granites are formed from molten material that is generally more felsic (lighter, more silica) which is from recycling of continental material. The mechanism for getting felsic material to occur at a spreading zone would be very difficult to explain based on our current knowledge of the process.

/geologist. but not a structural or oceanographic one.
posted by Big_B at 8:52 AM on May 23, 2013 [11 favorites]

I was thinking ballast stones too, but 10m is pretty big for a ship to have to move around into and out of a hull.
posted by Big_B at 8:53 AM on May 23, 2013 [2 favorites]

Does this mean that kitchen countertops will get cheaper?

Granite is incredibly rare. I mean you can excavate through a mile of granite and you'll only find a few kilograms of granite, tops. Perhaps this is a moment when we should kneel before the countertop manufacturers once again in an act of contrition.
posted by crapmatic at 9:01 AM on May 23, 2013 [4 favorites]

"Obviously, we don’t expect to find a lost city in the middle of the Atlantic."

Well, of course. If there is one the Maria Montez movie Siren of Atlas (based on the novel Atlantida) introduced me to, it is the theory that Atlantis is actually under the Sahara.

I mention this only because I love when incredibly obscure occult speculation births campy mid-20th century b-films.
posted by Bunny Ultramod at 9:03 AM on May 23, 2013 [4 favorites]

I wish they wouldn't say "continent." Small chunks of continental crust left over from an island chain dating to the rifting of South America and Africa does not constitute a "lost continent."

But it does get the Atlantis loons excited.
posted by General Tonic at 9:06 AM on May 23, 2013 [4 favorites]

What a coincidence! I lost 10 meters of granite near there a few months ago. Can you describe it a little better and I'll tell you if it's mine?
posted by drezdn at 9:09 AM on May 23, 2013 [7 favorites]

Granite is incredibly rare. I mean you can excavate through a mile of granite and you'll only find a few kilograms of granite, tops.

Huh? Maybe some of those fancy countertop stones are rare, but up here in Vermont, if you want granite, we got granite by the ton.
posted by beagle at 9:27 AM on May 23, 2013 [2 favorites]

It seems more likely to me that this would be a remnant of the old African & S. American proto-continent that slumped off at some point when they divided that may have existed as an island for a while? Are there any expanding rifts between this chunk of granite & the current coast of S. America?

The idea that it would have been a landmass during human history is probably ludicrous.
posted by Devils Rancher at 9:54 AM on May 23, 2013

General Tonic: a couple of months ago I learned that New Zealand actually sits on its own continent, Zealandia.... seems like maybe this "new continent" is the same sort of structure.
posted by Mars Saxman at 10:04 AM on May 23, 2013 [1 favorite]

The mechanism for getting felsic material to occur at a spreading zone would be very difficult to explain based on our current knowledge of the process.

Which is the whole point of this anomaly. You don't find granite in spreading zones. Therefore it must have been formed in a previous continental plate collision zone. For example, the Sierra Nevadas were formed by an oceanic plate diving beneath a continental margin, dragging down felsic continental sediments. The resulting melting creates volcanoes with granite formed underneath.
posted by JackFlash at 10:10 AM on May 23, 2013

Could it possibly be? Are the old legends true?... It is! It's the fabled lost city of Atlanta!
posted by mrgoat at 10:13 AM on May 23, 2013 [1 favorite]

if you want granite, we got granite by the ton.

I live in Texas - we have granite. Granite for everybody! You can go to salvage places and pick out a rejected slab that will make a fine desk, for cheap. That being said, the Examiner link, with the video caption that says "Scientists discover lost continent off Brazil" seems kind of hasty to me.
posted by PuppyCat at 10:14 AM on May 23, 2013

Ballast stones were recycled as cobblestones on the streets of places like Nantucket and Savannah. They're no bigger than what one person could lift alone.
posted by mareli at 10:17 AM on May 23, 2013 [1 favorite]

And you wouldn't be dumping ballast stones in the middle of the ocean, unless you're a pirate and you just got tons of booty from a sinking ship.
posted by mareli at 10:22 AM on May 23, 2013 [2 favorites]

Dammit! Wrong part of the ocean for R'lyeh.

You really expect a city of non-Euclidean geometries to restrain itself to a fixed point in space? Sounds to me like you've fled from the light into the peace and safety of a new dark age.
posted by Parasite Unseen at 10:32 AM on May 23, 2013 [4 favorites]

10 meters? I find it very suspicious that these ancient Atlanteans used the metric system.
posted by dances_with_sneetches at 11:08 AM on May 23, 2013 [4 favorites]

"Does this mean that kitchen countertops will get cheaper?"

Nope, just wetter.
posted by Eideteker at 11:41 AM on May 23, 2013 [1 favorite]

A cubic meter of granite weighs 2700 kg. So if this rock is 10m x 5m x 2m, that's 100 cubic meters or 270,000 kg (300 tons). I don't think it fell off a ship.
posted by jjj606 at 12:01 PM on May 23, 2013

I mean you can excavate through a mile of granite and you'll only find a few kilograms of granite, tops.

I presume this was meant in jest. It's like saying milk is rare, and you could spend a whole day drinking gallons of milk and only manage to drink a thimble-spoon.
posted by Bunny Ultramod at 12:03 PM on May 23, 2013 [2 favorites]

Deep sea expeditions by Japanese scientists named after contrived German acronyms finding mysterious lost artifacts? Remind me where I've heard this one before...?
posted by fifthrider at 12:31 PM on May 23, 2013 [2 favorites]

Sys Rq: WUT. Is this a thing?

Ballast stones

Also, that is how we get our countertops.

They're harvested from the ocean bottom? Seems like it would be a lot easier to just quarry them on land.
posted by IAmBroom at 12:47 PM on May 23, 2013

No, I mean they import it. On ships. Which may occasionally tip over.
posted by Sys Rq at 12:54 PM on May 23, 2013

These days, I think most countertop granite is harvested from unoccupied homes in far-off subdivisions in Las Vegas.
posted by afiler at 12:55 PM on May 23, 2013 [6 favorites]

Isn't it possible to generate small amounts of felsic igneous rocks at mid-ocean ridges from magmatic differentiation and/or fractional crystallization starting with mafic melt? And what we are dealing with in this case does appear to be a very small amount of felsic rock.

You would have to come up with a mechanism for that. Fractional crystallization comes from partial melting over a long gradient. This typically occurs in a subduction zone where the crust is very thick and sediments and oceanic crust are subducted to depths greater than 100 km.

Spreading zones are where the crust is very thin, less than 10 km. The hot mantle isn't partially melted -- it's just melted. No fractional crystallization cooling in only 10 km.

This is why volcanoes on continental margins are steep and explosive while volcanoes in the middle of the ocean are flat and relatively sedate. On continental margins differentiation occurs at about 900C and the magmas are more felsic, sticky and viscous. At spreading zones the magmas are hotter because of the thinner crust, 1500C, so no partial melting, more mafic, less sticky and less viscous.

Fractional crystallization has never been observed before in spreading zones. You go from very hot to very cold over a relatively short distance, as evidenced by the small grain size.

Another way to think about it is that in a subduction zone you are taking cold rock and very gradually making them hotter, allowing differential melting to occur. In a spreading center you are taking very hot rocks and quickly cooling them, so no fractional melting occurs.
posted by JackFlash at 1:56 PM on May 23, 2013 [5 favorites]

Seymour Zamboni: "Isn't it possible to generate small amounts of felsic igneous rocks at mid-ocean ridges from magmatic differentiation and/or fractional crystallization starting with mafic melt? And what we are dealing with in this case does appear to be a very small amount of felsic rock."

This is why I love geology. Lots of things are possible, but is it likely or feasible? I've seen mafic chunks bound up in Sierra Nevadan terrane, so maybe. But I thought magmatic differentiation and fractional crystallization was used to explain changes in volcanic composition over time, where the mafic minerals are expelled/otherwise removed from the melt first leaving the felsic material, in which case you're talking about the reverse scenario. This is beyond my expertise though.

Also magmatic differentiation is one of my favorite "hey I'm drunk let me explain geology to you!" buzz phrases. And I finish with "subduction leads to orogeny" if anyone is still listening.

On preview: I think JackFlash explained it much better.
posted by Big_B at 1:58 PM on May 23, 2013

Does this mean that kitchen countertops will get cheaper?

That's funny, because Brazil is already the source of a LOT of uba tuba granite (images). They have so much that it's the cheap stone material used in Brazil, or so I've been told.

As for this discovery, it's too early to tell much, but this article states:

The agency concluded that it was granite after analyzing video data. Also found in the sea around it was a large volume of quartz sand, which is also not formed in the sea. The bedrock is believed to be mainly basalt rock.

It's not a lot to go off of yet, but it's an interesting find in an area that hasn't been studied as well as other areas of the ocean.
posted by filthy light thief at 3:03 PM on May 23, 2013

Lost Lands Found by Scientists: Atlantis was a myth, but real-life lost lands do exist.
posted by homunculus at 5:46 PM on May 23, 2013

Comrade_robot: A cubic meter of granite weighs 2700 kg. So if this rock is 10m x 5m x 2m, that's 100 cubic meters or 270,000 kg (300 tons). I don't think it fell off a ship.

Harlan's Seamanship in the Age of Sail claims 500 tons of ballast for a 3 decker in 1783. USS Ohio was recorded with 700 tons of iron ballast. Ballast was a mixture of iron and stone; the iron in the form of cast iron pigs ranging from 56 to 320 pounds. On average 4 times as much stone was carried as iron. Some of the larger stone was permanently installed. I have no idea how large permanent ballast stones were, but it does not seem to me that it is impossible that a ship sank carrying large ballast.

Sooooo... because ships had iron ballast pieces that weighed up to 320 ounds, a ballast stone weighing 600,000 pounds is reasonable? Or did you confuse "tons" for "pounds"?
posted by IAmBroom at 5:23 AM on May 24, 2013

Because the act of lifting a 320-pound stone, versus lifting a 600,000 pound stone, would seem to be a somewhat different problem.

I know of one man who is hand-clearing a pass through a mountain, stone by stone, but I know of no one who is doing it in one shovelfull.
posted by IAmBroom at 12:26 AM on May 27, 2013

10 meters? I find it very suspicious that these ancient Atlanteans used the metric system.

Considering that only the US, Liberia, and Myanmar aren't on the metric system, it would be more suspicious if it was measured in Imperial.
posted by BlueHorse at 10:39 PM on May 27, 2013 [1 favorite]

BlueHorse: Considering that only the US, Liberia, and Myanmar aren't on the metric system, it would be more suspicious if it was measured in Imperial.

Almost suspicious enough to suggest a conspiracy...
posted by IAmBroom at 12:39 AM on May 28, 2013 [1 favorite]