21 comments on “Antarctica 1 – Introduction to Antarctica’s Volcanoes

  1. Great introduction, I did not expect so much tectonic diversity around Antarctica, and not that many volcanoes. I really look forward to your series of posts! Thank you, agimarc!

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  2. Awesome post Agimarc. I have often wondered where the volcanism in Antarctica comes from with no apparent subduction around anywhere (apart from the South Sandwich Islands). This post explains it nicely! But how amazing is that about the Transantarctic Mountains being purely the product of rifting! And surviving all that ice! Maybe the flow is not all that extreme due to the low precipitation and, being the high point, there won’t be so much erosion happening… random thoughts. Great piece.

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    • Thanks, Bruce. There is weirdness out there, as the West Antarctica Ice Sheet (WAIS) appears to protect the shield volcanoes of Marie Byrd Land from erosion. Don’t think I understand that a lot, but found it in a couple places. Cheers-

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      • Antarctica is very, dry. So dry, that’s it’s often referred to as a polar desert. This may be a factor in the more limited erosion of many Antarctic volcanoes,

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    • Bruce, the TransAntarctic Mountains are not purely the result of rifting – just as the seafloor of Drake Passage is not purely the result of colossal icebergs carried by ocean currents. Study the size of the Eltanin Tsunami waves, do the math and you’ll begin to realize the forces that carved out the Ross Sea and ultimately resulted in the West Antarctic Ice Sheet – which is more accurately described as a giant ice SHELF – because relatively little land is holding it in place, mostly it’s held there by rapidly melting ice shelves.

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    • Howdy Bruce –

      They’re talking about the subglacial volcanoes below the West Antarctica Ice Sheet (WAIS) in the West Antarctic Rift System (WARS). The white image with the maroon dots in the article are the known, surface volcanoes. Talk about this a bit in Part 3 which I loaded Friday. Stay tuned. Cheers-

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      • cool. sorry about the hysteria added by the journalists. I was just interested in them finding so many volcanos. Definite parallels to the Rift Valley. The WARS has the East Pacific Rise and its southern extension (too lazy to hunt for the name – wait, no I wasn’t, its the Pacific Antarctic Rise (PAR)) to its north in the same way that the African rift valley has the Atlantic MORB to the west.
        There is no subduction to be seen anywhere till you get to Kamchatka/the Aleutians in the case of the WARS and the Andes for the Rift Valley (and the Kermadec Trench to the east)
        It always seems counterintuitive to me to have another spreading system on one side of a MOR, but this is the second example after the Rift Valley.
        The WARS must be a pretty significant system to create mountains of that size even before glacial erosion is considered, implying that something is driving the rifting other than slab pull, which is what drives mid-ocean ridges. In other words, it looks like a mantle plume must be driving the rifting like the one posited for the Rift Valley in Africa.
        Long story short, the one hemisphere from Afar through to the Ross Sea and beyond is spreading and most of the subduction is getting accommodated on the western Pacific rim, maxing out near the triple junction by Kamchatka.
        Given the scale of it all, it is not too far-fetched to consider a flood basalt in the WARS (in a geological timeframe of course), which could have massive implications I guess.

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        • then again, as you state.. it now appears to be very slow moving or dormant so maybe all the action is behind is.

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  3. Sorry for all the disjointed thoughts.. the place really is a conundrum. We have an inactive rift with it seems, not a lot happening within it, but a great deal of intraplate volcanism off the rift in Marie Byrd Land, much like seamounts form off an extensional zone, except in this case they are erupting under a piece of crust (another point you already allude to… you see I am just slowly catching up to points you have already covered!) Really looking forward to the next instalments.

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  4. Great post! I was really curious about how volcanoes formed here, especially with the new revelations of additional volcanoes found in this area.

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    • CBUS, the seafloor is cracked there because of “lithospheric flexure” which resulted from a huge weight pushing down on the seafloor – that huge force was the water-weight known as the Eltanin Tsunami waves which completely decimated the Antarctic ice and the Antarctic land, Australia, New Zealand, the South Pacific Islands, Hawaii, etc. – the exact date for this cataclysm is found in the historic documents – it wasn’t millions of years ago.

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      • well, 2.51 ± 0.07  million years ago according to Wikipedia. That is one hell of an impact. I’d love to see the modelling of a 200m high tsunami hitting the ice shelf. Hardly bears thinking about. Assuming the tsunami was a series of long-period surges, the ice would have lifted and dropped like a huge raft. And presuming a large section of the ice shelf disintegrated, the isostatic rebound must have been both immense and sudden. Or the ice was too much of a barrier to be lifted, even by such huge waves and they just bounced off. Very intriguing to say the least.

        OTOH, you are not going to get volcanism just by cracking the crust (if that is what happened). You will also need a source of hot mantle and/or presence of volatiles to induce melting. My guess is that there are pockets of melt left over from the ancient subduction and/or rifting that causes the intraplate volcanism in Marie Byrd Land

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        • Bruce, if you do the math on the water weight and the resulting force of the tsunami waves, you’ll be able to conceptualize more of the dynamics. Hopefully, you’ll get that aha moment when it all begins to make sense.

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  5. I see Bogosloff has started chugging.. might mean a gradual transition away from a transient eruptive state towards dome building

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