Guest Video: The Columbia River Flood Basalts


Back in 2014, I took the train to Oregon from the East Coast (and highly recommend long train journeys–it’s a great way to see a lot of country). From Spokane, Washington, down to Portland, Oregon, the rail went through the Columbia River Basalts.

Flood basalts are incredible features anyway, but this landscape looked like an alien world. Long after the lava had hardened, ice-age megafloods pounded the land, carving new channels, deep holes, and strange-looking contours in the dark rocky cliffs.

Those hours of travel were fascinating, but it would have remained just a nice travel memory had a paper on the Columbia River Flood Basalts not made the news this past week.

It turns out that the Columbia River Flood Basalts very probably changed Earth’s climate, back in the day (the Miocene), causing it to warm up for several million years.

So I looked around and found the video below. Even though it is only a draft from Columbia Gorge Community College, it has great views of the basalts. And there is a geologist there to tell you what you’re looking at! The quality is rough in spots, but hang in there during the part where it goes black; video will return.

And even in draft form, this really does show the scale of these things:




A little lagniappe. It’s entertaining, even if it is long (a little over an hour) and in lecture form, and gives more information and perspective:


Edited September 23, 2018, 8:01 p.m. Pacific.


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Guest Video: Öræfajökull


Let’s all start practicing this new Icelandic name now, just in case this restless volcano does go off in our lifetimes!



Given Öræfajökull’s size and its history, an eruption could be bad (though you never know what a volcano is going to do until it does it).

There are a lot of gloom-and-doom videos and sites out there, but here are some online information sources I’ve found reliable:

  • Icelandic Met Office
  • The Smithsonian’s GVP page.
  • Various posts by Dr. Erik Klemetti, including this one, and this.
  • Jón Frímann Jónsson–an interesting though not expert lay source whom many of us online volcanophiles relied upon during the lead-in to the 2010 eruption of Eyjafjalljökull.
  • London Volcanic Ash Advisory Centre (VAAC) website. This should be the first place you check, if you want to know if Öræfajökull has really erupted. The link to Toulouse VAAC on this page is also helpful.

Featured image: Satellite image of Öræfajökull, showing cauldron of glacial meltwater in late 2017. Antti Lipponen, CC BY 2.0.


1,939 Years Ago This Week, Vesuvius Erupts


On the left, a contemporary view of Vesuvius in 79 AD, as seen in artwork in a Pompeiian villa. They had no idea it was a volcano.

On the right, Vesuvius after the eruption, as seen from an excavated Pompeii. That bump on the right is all that remains of the former structure. The double-peak cone formed during the 79 AD eruption.





Pliny the Younger to Cornelius Tacitus, soon after the disaster:

Thank you for asking me to send you a description of my uncle’s death so that you can leave an accurate account of it for posterity(1); I know that immortal fame awaits him if his death is recorded by you. It is true that he perished in a catastrophe which destroyed the loveliest regions of the earth, a fate shared by whole cities and their people, and one so memorable that is likely to make his name live for ever: and he himself wrote a number of books of lasting value: but you write for all time and can still do much to perpetuate his memory. The fortunate man, in my opinion, is he to whom the gods have granted the power either to do something which is worth recording or to write what is worth reading, and most fortunate of all is the man who can do both. Such a man was my uncle, as his own books and yours will prove. So you set me a task I would choose for myself, and I am more than willing to start on it.

My uncle was stationed at Misenum, in active command of the fleet.(2) On 24 August, in the early afternoon, my mother drew his attention to a cloud of unusual size and appearance. He had been out in the sun, had taken a cold bath, and lunched while lying down, and was then working at his books. He called for his shoes and climbed up to a place which would give him the best view of the phenomenon. It was not clear at that distance from which mountain the cloud was rising (it was afterwards known to be Vesuvius); its general appearance can be best expressed as Continue reading

Guest Video: Volcanoes and Glaciers


Did you know that Yellowstone Supervolcano was covered by some 4,000 feet of ice during the last ice age?

According to the Yellowstone Volcano Observatory (YVO), the hydrothermal system at the volcano really “lit up” after all that ice melted away.

But what would have happened had the volcano erupted while a glacier sat on it?

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Guest Videos: Gakkel Ridge Volcanoes

Gakkel Rise, between Greenland and Siberia, is named after the Soviet geoscientist who first mapped the Arctic Ocean’s floor. It’s a long, underwater mountain range that hosts a complex of volcanoes with delightful names like Jessica’s Hill, Duque’s Hill, Oden, Thor, and Loke (not the Marvel spellings of “Odin” and “Loki,” but the same Norse-god reference).



While at least some of these volcanoes are active, Jessica and friends sit roughly 13,000 feet (4000 meters) below sea level–too far down to influence pack ice in any way.

The last known eruption, probably in 1999, scattered debris over Oden and Loke. A 2007 remote submarine expedition also found recent pyroclastic deposits, though that is not recognized as another eruption.

These were history-making discoveries. Until then, volcanologists hadn’t known that explosive eruptions can happen at such depths (slightly below the RMS Titanic wreck’s depth), where pressure is almost 400 times that on the sea surface.



But the Gakkel Rise has always surprised scientists, at first in the 1950s by being pretty much exactly where Yakov Yakovlevich Gakkel predicted it would be found.

When the plate tectonics era dawned, this northern extension of the Mid-Atlantic Ridge–a spreading center–was considered to be nonvolcanic. However, in 1999, nuclear subs detected volcanic activity there, and today Gakkel Ridge is known to be the slowest spreading center in the world–much slower than the Mid-Atlantic Ridge, and even more of a slowpoke than the Mid-Cayman and Southwest Indian ultraslow spreading ridges.



The potential mineral wealth that he mentions at the end of the video complicates the picture. Along with untapped gas and oil deposits, it’s a major motivating factor in the Arctic territorial claims we mentioned in yesterday’s post about the namesake of nearby Lomonosov Ridge.

The area needs exploration for scientific reasons, not just for geopolitical advantages.

What little is already known about Gakkel Rise volcanism is unusual. There may even be a giant caldera there, although I have only found one reference to it. I don’t know whether that’s because it is such a new paper (2017) or because this might not be a widely accepted hypothesis yet.

Anyway, as another WordPress blogger says (in a much better post):

The Gakkel Ridge is one of the most remote tectonic regions on the planet. Yet it has volcanic activity and life. It is a spreading center that connects the active Mid Atlantic Ridge to the non-spreading Eurasian Plate. Not unexpectedly, volcanic activity is found closer to the MAR, though hydrothermal vents are found in the half of the ridge closest to Greenland and the MAR. It is home to the deepest pyroclastic activity ever observed. It also has some of the thinnest oceanic crust ever observed and may even have mantle rocks exposed to the ocean. Like all our volcanic regions, the more we look at this, the more we find things that we never expected. Which is why we do this.



Sources:

Moran, K.; Backman, J.; Brinkhuis, H.; Clemens, S. C.; and others. 2006. The Cenozoic palaeoenvironment of the Arctic Ocean. Nature, 441(7093): 601.

Nikishin, A. M.; Gaina, C.; Petrov, E. I.; Malyshev, N. A.; and Freiman, S. I. 2017. Eurasia Basin and Gakkel Ridge, Arctic Ocean: Crustal asymmetry, ultra-slow spreading and continental rifting revealed by new seismic data. Tectonophysics, via PDF.

Piskarev, A., & Elkina, D. (2017). Giant caldera in the Arctic Ocean: Evidence of the catastrophic eruptive event. Scientific Reports, 7, 46248.


Guest Videos: Laguna del Maule Volcanic Complex


First off, here’s a skiing video, without a single mention of volcanoes. But everything they are travelling over, under, around and through is part of the Laguna del Maule volcano complex on the Chile-Argentina border.



Yes, it’s an active volcano. In fact, until last year it seemed the most likely candidate for the world’s next supereruption.

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Galapagos Volcanoes


Here is a 2013 post I did on the other blog that is relevant now because there are two eruptions going on there at the moment:

La Cumbre:

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and Sierra Negra:

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Ah, the Galapagos! Thinking of Darwin and giant turtles now?

Well, the land itself – a volcanic archipelago – is alive, too.
 

 
Per the accompanying text for that NASA Earth Observatory flyover, Straddling the equator approximately 1000 kilometers to the west of the South American mainland, the Galapagos Islands lie within the heart of the equatorial current system. Rising from the sea floor, the volcanic islands of the Galapagos are set on top of a large submarine platform. The main portion of the Galapagos platform is relatively flat and less than 1000 meters in depth. The steepest slopes are found along the western and southern flanks of the platform with a gradual slope towards the east. The interactions of the Galapagos and the oceanic currents create vastly different environmental regimes which not only isolates one part of the Archipelago from the other but allows penguins to live along the equator on the western part of the Archipelago [because of the cold Humboldt or Peru ocean current, shown in blue…Barb] and tropical corals around the islands to the north. The islands are relatively new in geologic terms with the youngest islands in the west still exhibiting periodic eruptions from their massive volcanic craters.

 

The Galapagos Islands are dramatic from the ground …

 

 

… or from a boat, at night, about a quarter-mile offshore (the military tries to evacuate tortoises and other animals at risk when there is an eruption): Continue reading