Possible new island as large as Florida…or something weirder
The Deccan Traps, the Siberian Traps, the Columbia Flood Basalts, and the Lakhi eruption in Iceland are all from when the Earth ripped open along a large seam on land. Now, volcanic eruptions produce basalts, which do not as a rule produce continents—continents, which ‘float’ on the mantle, are granite, a lighter rock than basalt. Hawaii, however, is basaltic…some have even suggested that its hot spot WAS the Siberian Traps hotspot, as the overlying plates migrated over time.
At a time yet to come, a hundred million years from now, we may see this break out—from our orbiting station, we hope.
Continental Drift — The maps I’ve seen of what they think Earth looked like over time all seem to show the same continental plates moving and reassembling. Discussions talk about how landmasses can be formed, move apart, together, or be subsumed, reabsorbed.
But those never seemed to discuss how new large landmasses (such as continents or plates) might be formed. Usually, they’d say new land would emerge from two plates moving apart, or from volcanoes forming island chains as plates moved past them.
What’s to prevent some spot from forming that ejects a lot of lava / magma to form a new landmass such as a very large “island continent”? Why not have a weak spot break off part of a continental plate and push new crust up from below? I’m thinking of the analogy of what happens when pies and cakes and casseroles form crusts as they bake. Get a weak spot, disturb the crust somehow, and bang, you’ve got a new patch. The principle seems the same, just slower time scale and larger size scale.
OK, it could form a larger “island”. The thing that makes the Hawaiian Islands “small” (aside from the fact that Molokai had one helacious landslide) is that the Pacific Plate is moving relative to the hot spot. If the two were relatively stationary then there would be one large island, rather than a chain of islands, shoals, and seamounts. It would be made of basalt, essentially cooled mantle. Basalt is heavier, more dense, than continental rocks–the reason they float on the mantle. As more of the basalt was brought to the surface, as at Kiluea, the cooled rock got heavier, gravity would pull it down in much the same way mountain chains have deep roots. The deeper the hotter–it’s cooled basalt–it melts but has no density gradient to make it want to float. But the island would exist until it got subducted at a continental plate boundary. Then when it melted only a relatively small amount that had been transformed by surface weathering would float to the surface.
The reason the Hawaiian Islands exist is they’re relatively tiny, and the dense water surrounding them helps hold them up. They’re more like obelisks than pyramids. From the sea floor, The Big Island is incredibly tall and skinny, say in comparison to Mt McKinley.
So yes, you can get a large island from a super-volcano erruption at sea, but it doesn’t survive subduction as do lighter rocks, granitic plutons like Yosemite’s Half Dome etc. It would have to get jammed into a continental edge and get supported by the lighter continental rocks around it, as Mt Nebo outside Roseburg, OR.
Dang! Typo! 🙁 One “r” in eruption! I want an editor!!!
Actually, if you look at the crust around the Hawaiian islands, it dips in around their weight. It kind of looks like one of those rubber-sheet gravity well diagrams.
That demonstrates an important revelation: the crust is not rigid! 🙂
There is some discussion of the possibility that our granitic continental material arrived by asteroid, to float on the basalt. But indeed, for all I know as an amateur in geology, we could be looking at the sub-basement formation of a new plate. Of course the Earth is of finite size, so what comes up, an equal amount must go down at the subduction zones. Interesting, however, that the Pacific is our ‘hot’ zone, our Ring of Fire. Could they possibly have discovered one reason it is so active?
It’s really interesting that this particular place is poised to create a new potential continent, when Australia, the next door neighbor, is so geologically stable. Australia is one of the least altered continents, whose land-building processes happened in the distant past. It has a few thermal springs and such, but nothing literally earth-shattering.
True—yet there is out in that area of the map a subsea volcano that’s breached the surface repeatedly and been eroded back. They’ve been watching that one for years.
I’ve always thought of continent formation like the foam on top when you are making jelly, or clear jam for the Queen’s English speakers. It rises to the top slowly at first, but after a while it seems to stop unless you skim the foam, after which it starts to put up foam more quickly than it had in the first place. The idea of somebody coming by and skimming off the continents is rather horifying to me!
I don’t think geologically it will “foam more quickly”, but yes, it’s something like that.
Nobody’s going to be “skimming off the continents”! 🙂 It’s always amusing when people speak of the California coast west of the San Andreas Fault “falling into the sea”. They float! If you have a boat dock out in the lake and one of the boards falls off, does it sink without the rest of the dock to hold it up?
To the extent that anything can be said to get skimmed off (think central California’s Coast Ranges), mostly it’s the sediments that washed off the continental shelf to the “abyssal plain” at the leading edge of the continent, e.g. West Coast. The sediments in the Atlantic, the trailing edge, just keep piling up.
The West Coast has over-ridden part of the East Pacific oceanic spreading ridge. But the rock at the “mid-oceanic” ridges is basalt (think “basal”, though the etymology is more complicated than that. The Latin teacher can explain. 😉 ), so when the eastern side went down into the subduction zone, it melted away. But being at essentially the same density as the mantle, it had no “incentive” to rise. What’s causing the volcanoes in the Cascades is the sediment that wasn’t skimmed off the west side as it has been subducted. It does want to rise when it gets melted.
BTW, our last subduction zone magnitude 9 (think 3/11 Tohoku/Sendai quake) was January 26th, 1700. You can pretty much kiss the economy of the West Coast (as in almost everything west of the Rockies: Vancouver, Seattle, Portland, perhaps even San Francisco) good-bye when we get the next one.
Scanned for typos. But there must be one that won’t show itself until I hit “Post Comment” 🙁 )
Washington state consists of a number of islands that were rammed up against Idaho, which at the time had a coast…just endless docking of a batch of islands…which didn’t sink. Of course we then got a flood basalt burying the whole evidence under a mile or so of basalt lava flows, so it’s a bit of a patchwork with a blanket thrown over it. We had wooly rhinos once—but then the post-ice-age floods swept through and cut deep channels like the Columbia Gorge and swept all those poor rhinos out into the Pacific…
If you ever have to drive down I5, say to the Bay Area, on the south side of Roseburg you’ll swing around Mt Nebo. On the south side, before the McLaine Ave on/off “ramp”, notice the pillow lavas exposed when they blasted for the roadway. Textbook! 🙂
So there’s no Rhine, Rhone, or Rhino about, then? Kein-o Rhino? … I’ll go stand in the corner!
North America really was a happenin’ place, though. Wooly rhinos and mammoths, camels and llamas, horses, giant armadillos (oddly not chasing beer trucks), giant sloths, opossums, all sorts of critters, even some with no modern equivalents.
Imagine looking out and finding one of those guys on your front lawn, eating the daisies.
(Huh, that reminds me of one of the first “science fiction” stories I think I ever read, as a little boy in elementary school. It seems this boy found a giant egg and brought it home… and wound up with a Stegosaurus! … I don’t recall the name of the book. Too many years ago. Hmm, I might have to get it if I did know the name. It was a nice little tale for young readers.)
I believe the book you’re remembering is The Enormous Egg (no, seriously!) by Butterfield. Rather Centerburg Tales or Henry Reed-ish. Sorry 😀
That might be it. It’s worth the order to find out. When I looked it up, I also found this:
The Shy Stegosaurus of Cricket Creek [Paperback]
Evelyn Sibley Lampman (Author), Hubert Buel (Illustrator)
(A brother and sister are out fossil hunting with their parents, and the kids find a real live Stegosaurus, it says.)
Which looks like it might be the one. Also cheap enough to see if it’s the one.
Either look good for the young scifi fan or the young-at-heart scifi fan in the house.
Currently reading: “Krakatoa: The Day the World Exploded, August 27, 1887” by Simon Winchester. Excellent info on new land.
Years ago I came across an article with extracts from diaries and letters about the winter of ‘the year without a summer’ after Krakatoa. One woman wrote that when she washed the dishes the piled plates froze together before she could dry them. The last few days without power I kept remembering that article…
Human will evolve so much in 100 million years, space stations may be an anachronism. Ursula K. Leguin wrote a book, “Always Coming Home” about a time much closer than that when humans have moved back to a more Earthbound lifestyle. But in a 100 million years, will there be humans to see any new continents, or will there be an Earth, or will the continents have drifted so much with intervening glaciations and asteroid punches, that a person who left now at light speed and came back would not even know he was home.
Astronomical/Geological scales of time like that are difficult for us to think about. They are so far outside of our personal experiences they are virtually impossible to compare.
One of the things that works for me is thinking of the KT Boundary 65MYA. Dinosaurs went extinct. Mammals were still insignificant little rat-like things, yet to be ancestors of whales. About that time island India had rammed into Asia and was pushing up the Himalayas. Closer to home, the Rocky Mountains were still building (the Laramide Orogeny), only about half-way through their process.
100 million years is truly a very long time. But to imagine what our descendants might be like we must first determine what sort of evolutionary pressures might force us in one direction or another. After all, the ants and cockroaches are still with us! 😉
Cockroaches. Definitely cockroaches, and I have met a good many of them!
I think they’ve read your books…
http://www.extremetech.com/extreme/148329-earth-skimming-da14-asteroid-contains-195-billion-of-minerals-if-we-can-catch-it
?!?Smooshed to smithereens!?!
It’s the slowing it down part that’s hard. Think of an ant trying to catch an MLB fastball…you could take a heckuva ride…and hope goes-around comes-around for another pass…
But a pass this close will have attracted it and bent its orbit. Its velocity won’t have changed significantly (any speed-up on the inbound leg will be more or less subtracted on the outbound leg), so it won’t have been lifted or dropped to a higher or lower orbit around the Sun. But if I have my interpretation of elliptical orbits straight (and absent precession or a near pass to another planet that bends it yet again), it will pass through this volume of space again on its next orbit. I haven’t heard anything about the effects.
For the last month or so there have been a lot of earthquakes in the area of the Solomon Islands. They seem to be within the zone in the article. The one island ( I can’t remember the name of it) The capital is Lata, had so many quakes going on they couldn’t get to it to help the people for several days.
There was a pretty big one, ~6.8 IIRC, a week ago (or so) near Sanata Cruz Island in the Solomons. It produced about a 5′ tsumani, but I didn’t hear of much damage other than locally. (OTOH, many of the atolls don’t get that high.)
I remember that one; it scared the poopies out of Hawaii with the “You’re on watch — no, you’re not — yes, you are” on again off again tsunami alerts. It later turned out that Hawaii was never under direct threat, that the alerts were a software artifact. If anything goes off anywhere around the ring of fire, Hawaii sits up and says ‘Scuse me?!? It’s been happening far too often lately.
Tsunamis are sort of a big deal around here, the one about two years ago did a lot of damage to the harbor and I don’t think it was even 5′ here. Half an hour south got creamed, but then they’ve got a lot of bad history with tsunamis.
We heard about the Santa Cruz Islands quake, but it was pretty quickly forgotten when they figured we were outside the zone. However, our local fault tends to go through spells where its gassy, and spells where its quiet. Every now and then it farts and people get excited. It never has amounted to anything, thank goodness! At least with the tsunamis originating on the other side of the world we get warning. If the local fault gives way, we’re going to have MAYBE 10 minutes, once we pick ourselves up off the ground!
Hawaii has a history of big slumps and underwater landslides90 (yes, Zorro, I love you too!), just look at the underwater topography. If the chunk of the Big Island on the Big Crack gives way, people below the 2000′ level are going to have at most 20-25 minutes to find much higher ground!
A repetition of the Molokai landslide will make for a very bad day, not just for Hawaiians but also for sombody on the West Coast, Mexican Riviera, Japan, Coastal Alaska, Chile, or the whole South Pacific islands.
Interesting. I tend to follow geology ’round the world, but I’d missed that one.
Since the end of January, there have almost 200 quakes in the area of 4 to 8 magnitude. It finally has started to settled down a bit the last couple of days. I was looking at USGS real time map after a small earthquake here in Ohio, and check it periodically out of curiosity. Mostly all you’ll find in the news is about the tsunami.
I expect you’ll pay a few bucks for earthquake insurance where you are. Insurance companies remember the New Madrid quake of 1811-1812. Memphis has continuous monitoring.
The New Madrid Fault is one of those that is continually doing little jitters, in the 1-2 magnitude range, with a swarm of slightly larger ones every so often. Just to remind people that it can come up with a ripsnorter if it wants. I’m not surprised that it figures into insurance actuary tables, but more for the potential damages if it goes, not because it’s particularly likely to. The Midwest doesn’t have the same press as the San Andreas Fault, and it’s rare to find buildings with earthquake reinforcement; a lot of the construction is older and couldn’t stand up to a good 7+ shake.
One year, one of my friends was commuting between Los Angeles and Dayton, Ohio, via St Louis. He described it as ‘the world market for used brick is not that big’. (It was an interesting job: they were setting up a disk drive so it would work with both a PDP-10 and a Vax. For hardware reasons, it had to be the PDP-10’s physical drive. DEC said it couldn’t be done – but they did it.)
There’s some thought that these things can ‘chain’, ie, that activity just kind of runs around the ring, barring some locally strange condition. And the places that need to watch out may be those that have been quiet too long.
Like us! 413 years. 😉
I seem to remember something about ‘chaining’ happening in Iceland (TV program not so long ago) and the vulcanologists are watching that part of Iceland very closely.
Maybe it ‘sloshes’, like jelly when it’s cooling and you move the jar?
We held a Conquest or two in the Hyatt Regency KC, which has a huge rock with a crack in it near the escalators in the lobby. Local rumor says that’s the start of the New Madrid fault.
Have you seen the news about the meteor shower in Russia? At least 400 injured.
http://www.bbc.co.uk/news/world-europe-21468116
A thousand injured. Wow. It’s possibly an ‘associate’ of the one we’re watching pass us at close range. You watch the one hand and the other one gets you. Poor folk! Glad it wasn’t worse!
I wouldn’t bet against gravitational attraction of this small asteroid having acquired a “wingman”. Unless the Russians had a good track on it before it dived into the atmosphere, I’m not sure we’ll ever know for sure.
Nope — completely different vector. This one came from out of the Sun; it was a sun-grazer, and a relatively tiny one, which is why we didn’t see it until it clipped us. Tunguska Lite?
NASA press release:
http://www.jpl.nasa.gov/news/news.php?release=2013-061
Discovery had more videos at http://news.discovery.com/space/asteroids-meteors-meteorites/huge-fireball-explodes-over-russia-130215.htm
They are pretty awesome – or awe-full – the original sense of the word.