From the UNIVERSITY OF SOUTHAMPTON the “splode” department comes this interesting claim that tries to make CO2 the driver rather than volcanoes themselves. It looks like a big leap of speculation to me.
Around 720-640 million years ago, much of the Earth’s surface was covered in ice during a glaciation that lasted millions of years. Explosive underwater volcanoes were a major feature of this ‘Snowball Earth’, according to new research led by the University of Southampton.
Many aspects of this extreme glaciation remain uncertain, but it is widely thought that the breakup of the supercontinent Rodinia resulted in increased river discharge into the ocean. This changed ocean chemistry and reduced atmospheric CO2 levels, which increased global ice coverage and propelled Earth into severe icehouse conditions.
Because the land surface was then largely covered in ice, continental weathering effectively ceased. This locked the planet into a ‘Snowball Earth’ state until carbon dioxide released from ongoing volcanic activity warmed the atmosphere sufficiently to rapidly melt the ice cover. This model does not, however, explain one of the most puzzling features of this rapid deglaciation; namely the global formation of hundreds of metres thick deposits known as ‘cap carbonates’, in warm waters after Snowball Earth events.
The Southampton-led research, published in Nature Geoscience, now offers an explanation for these major changes in ocean chemistry.
Lead author of the study Dr Tom Gernon, Lecturer in Earth Science at the University of Southampton, said: “When volcanic material is deposited in the oceans it undergoes very rapid and profound chemical alteration that impacts the biogeochemistry of the oceans. We find that many geological and geochemical phenomena associated with Snowball Earth are consistent with extensive submarine volcanism along shallow mid-ocean ridges.”
During the breakup of Rodinia, tens of thousands of kilometres of mid-ocean ridge were formed over tens of millions of years. The lava erupted explosively in shallow waters producing large volumes of a glassy pyroclastic rock called hyaloclastite. As these deposits piled up on the sea floor, rapid chemical changes released massive amounts of calcium, magnesium and phosphorus into the ocean.
Dr Gernon explained: “We calculated that, over the course of a Snowball glaciation, this chemical build-up is sufficient to explain the thick cap carbonates formed at the end of the Snowball event.
“This process also helps explain the unusually high oceanic phosphorus levels, thought to be the catalyst for the origin of animal life on Earth.”
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It would seem to me that the original assumption of “Snow Ball Earth” conditions is incorrect. There must be another explanation for the deposits sited…pg
Please suggest an alternative explanation of the evidence for Snowball Earth episodes. No geologist has been able to do so despite decades of trying. Too bad there isn’t an Earth Science Nobel for you to win.
Oh yeah.
If plausible there was a recent volcanic event, such as described, at the North Pole back in 1998 or so.
Under water camera brought back evidence of pyroclastic flows in the recent past.
So did unusual amounts of CO2 or Phosphate show up there?
kind of strange how “the volcanoes done it ” back then, yet we are assured that today underwater volcanoes have minuscule effect.
This kind of handwaving gets dangerous, the hysterics had better calm down before someone loses an eye.
So where was the location of super-continent Rodinia?
How about it was centred right over the South Pole. As in Antarctica times 20. Which is where it was.
Glaciers build up 5 kms high over the centre load-points, spread across all of the land that it is within reach – Albedo rises to 45% – even more glaciers build up everywhere except the 20S-20N tropics – ie Snowball Earth. 635 million years ago, the average Earth temperature is -25C from today.
Snowball Earth ends when super-continent Rodinia starts breaking apart – as all super-continents do eventually – super-continents eventually heat up the underlying mantle and do not allow energy from the mantle to escape. Super-continents depress the mantle in central loading areas. ie. the heat builds up until rift valley volcanism breaks out and breaks the super-continent apart and starts the next cycle of continental drift.
Rodinia splits apart into several pieces which gradually move away from the South Pole and the glaciers start melting and Albedo goes down to 40% – more glaciers melt – Albedo goes down to 30% and the landmasses have left the South Pole. The South Pole is now ocean covered where glaciers cannot build up.
Snowball Earth ends – volcanoes have been erupting for 50 million years as the super-continent is slowly split apart and replaced by ocean.
Now take Rodinia and place it centred over the Equator as in Pangea instead of the South Pole. Now the Earth is as hot as it can get – as in 265 million years ago with Pangea when the average Earth temperature was +10C from today.
No CO2 needs to be involved in this explanation at all.
Plus many.
Bill,
Well said, as usual.
The continents were arranged a little differently during the two Cryogenic megaglaciations, but your geologic explanation for termination is far more plausible than the magic gas as cause.
Thanks!
Bill
Could you put all your thoughts on climate and geology into a book? (Or several?)
Or have you already?
It is quite well established that there was extensive glaciation quite close to the equator during the Cryogenian. This is shown by the “frozen in” magnetism in glacial deposits that show that they were emplaced at low latitudes (though on an “iceball earth” no glacial deposits could form – they are formed by moving glaciers, which requires snowfall).
I’ve pointed this out to the science-lite participants in the effect of volcanoes on the chemistry of the ocean. Basalts are MAGNESIUM SILICATES. Calcium is largely contributed from land erosion.
Yup. Even explained by rock type upthread.
Excellent discussion here, many good points presented for and against the snowball/slushball Earth. I will bookmark this topic for later review. 🙂
The uncertainties are so large any conclusions are not much more than mere hand waving magic induction.
Although I’ve always been skeptical of the ‘snowball Earth theory, I’ve tried to keep an open minding while waiting to see the evidence for the concept. So far, all I’ve seen is wild, mostly absurd, speculation and no conclusive evidence. Maybe I just haven’t seen the right paper with definitive data. What I do know, is that CO2 ALWAYS lags temperature in ice cores, so the notion that CO2 was responsible for a super ice age that covered the entire Earth with ice for millions of years is sheer geofantasy.
It’s easy to find papers offering compelling evidence of at least three such global glaciations of varying intensity:
Huronian (article relies IMO too heavily on CH4 as an explanation, but evidence for low latitude and altitude glaciation is convincing):
http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3121.2006.00672.x/abstract;jsessionid=ACBBAEDB8478C9AA12B5E4EEB9F516E8.f01t04
Sturtian
http://science.sciencemag.org/content/327/5970/1241
Marinoan:
http://science.sciencemag.org/content/327/5970/1186
There were also papers in 2005 on Ir spikes which coincided with the Sturtian and Marinoan deglaciations, as Ir-enriched space dust which had accumulated on the ice sheets was washed into the sea or left behind on land after the ice melted.
I live on a glacial bench. There’s nothing passive about ice. Speculation about the unknowable isn’t science, it is guesswork. I have an awful feeling taxpayers funded this fishwrap.
Dear Scientists – please stop tweeting your speculations and suppositions about the unknowable. And if you ever write that something “may” happen have the brass to write that same something may not happen.
Just another “stunning ” example of There’s nothing CO2 can’t do. Amazing gas that CO2.
Can we just stop calling “climate science” science?
This is nonsense. The mid oceanic ridges (spreading centers) Gernon is referring to are characterized by the nonexplosive eruptions typical of basaltic magmas with low viscosities and low gas content. Under water they form the famous pillow lavas. The explosive eruptions are common with andesitic-rhyolitic magmas with high viscosities and high gas content.
Indeed this is nonsense, pure and simple. Hyaloclastite is normally formed when volcanoes erupt under glaciers, not under water. it is very common on Iceland (it is called móberg in Icelandic).
As a matter of fact the linkage to glaciation is so close that the distribution of the móberg can be used to map the extent and thickness of the ice at the time of the eruption. As soon as a volcano penetrates the top of the ice it changes eruptive style and starts producing ordinary lava instead. Herdhubreidh volcano is a beautiful example, it looks almost like a western mesa but is actually a móberg cone with a “conventional” lava plateau on top.
http://mw2.google.com/mw-panoramio/photos/medium/57268695.jpg
For this harebrained scheme to work would require:
1. Mid ocean-ridges subaerial or at very shallow depth
2. A completely different style of eruptions than is normal at ridges (explosive rather than the normal effusive or dyke intrusion)
3. A completely different chemistry at the ridges with ultrabasic/carbonatitic magma, normally found only in intra-continental or island-arc settings.
The last is the killer since it requires a planet with a completely different chemistry of the mantle than the Earth has.
Not having read the paper I can only comment on what is written on this thread. Gernon points out:
He seems to forget that there are two sides to a coin: when new crust is formed along the mid-ocean ridges somewhere else crust is being consumed. That “somewhere else” are the subduction zones along which there is another type of volcanism, the explosive type. Most of todays explosive eruptions are taking place there (along “the ring of fire”) e.g. Krakatoa and Pinatubo etc.
“This is nonsense. The mid oceanic ridges (spreading centers) Gernon is referring to are characterized by the nonexplosive eruptions typical of basaltic magmas with low viscosities and low gas content. Under water they form the famous pillow lavas. The explosive eruptions are common with andesitic-rhyolitic magmas with high viscosities and high gas content.”
Not so fast there 🙂
The mid ocean ridges DO explode violently, and have even been recorded happening “live”. Known about it for 8+ years or so now.
http://www.noaanews.noaa.gov/stories2009/20091217_volcano2.html
“Water from the volcano is very acidic, with some samples collected directly above the eruption measuring somewhere between battery acid and stomach acid. Julie Huber, a microbiologist at the Marine Biological Laboratory, found diverse microbes even in such extreme conditions.”
“Mission scientists believe 80 percent of eruptive activity on Earth takes place in the ocean, and most volcanoes are in the deep ocean. Until this discovery, NOAA and NSF had sponsored research on submarine volcanoes for 25 years without observing a deep-ocean eruption. Scientists believe further study of active deep-ocean eruptions will provide a better understanding of oceanic cycles of carbon dioxide and sulfur gases, how heat and matter are transferred from the interior of the Earth to its surface, and how life adapts to some of the harshest conditions on Earth.”
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So, 80% of ALL of the eruptive activity on Earth takes place in the ocean…and these eruptions are spewing out stuff that is somewhere between battery acid and stomach acid….acid…..ACID….”acidifying the oceans”.
WHEN will the climate scientists LISTEN? If oceans are acidifying and warming, isn’t the Occam’s Razor point where we go…Um….it’s coming from IN the oceans instead of magically somehow in a not explainable way coming from the atmosphere above the ocean?
4 TIMES the amount of Co2 and heat and sulfurs and chemicals and acids that are “put into the air” by land volcanoes is being pumped into the ocean 24/7 !! And both “hot” water AND hot Co2 rises….to warm higher layers than bottom ocean layers. Right? And sea creatures are LIVING and THRIVING in the mineral rich and VERY warm water around hydro thermal vents in the ocean floor.
I refuse to take ANY climate scientist seriously until we have mapped the entire ocean floor, quantified the amount of heat/CO2/acid being pumped into the oceans by marine volcanism, quantified how THAT underwater stuff is cycled into our atmosphere, and then entered into the models along with every other thing we haven’t put into them yet.
Aphan, I am not saying that submarine volcanos cannot be explosive, I am saying that mid-atlantic ridges where new crust is being formed are basaltic (Iceland for instance) and that those are not explosive, in contrast to the ones around the Pacific (submarine or not) which are lining the subduction zones where crust is being consumed.
You don’t seem to understand the difference between the two types.
You did not say “mid atlantic”, you said mid-oceanic.
And ANY kind of magma becomes explosive depending upon chemical concentrations in it and the pressure/force driving it.
http://www.nature.com/ngeo/journal/v4/n4/full/ngeo1104.html
“The abundance of volatile compounds, and particularly CO2, in the upper oceanic mantle affects the style of volcanic eruptions. At mid-ocean ridges, eruptions are generally dominated by the gentle effusion of basaltic lavas with a low volatile content. However explosive volcanism has been documented at some ocean spreading centres1, 2, 3, indicative of abundant volatile compounds. Estimates of the initial CO2 concentration of primary magmas can be used to constrain the CO2 content of the upper oceanic mantle, but these estimates vary greatly4, 5. Here we present ion microprobe measurements of the CO2 content of basaltic melt trapped in plagioclase crystals. The crystals are derived from volcanic ash deposits erupted explosively at Axial Seamount, Juan de Fuca Ridge, in the northeast Pacific Ocean. We report unusually high CO2 concentrations of up to 9,160 ppm, which indicate that the upper oceanic mantle is more enriched in carbon than previously thought. We furthermore suggest that CO2 fluxes along mid-ocean ridges4, 5 vary significantly. Our results demonstrate that elevated fluxes of CO2 from the upper oceanic mantle can drive explosive eruptions at mid-ocean ridges.”
I’m not disagreeing with the point that basaltic eruptions OFTEN create pillow lava at mid ocean ridge points. BUT it is FALSE to claim that basaltic magma entry at the mid ocean ridges is never explosive or violent.
Aphan, you start splitting hairs. There was no Atlantic during snow ball earth so I have to generalize and call it mid-ocean ridges (places where new crust is being formed). The point I am making is that Gernon was assuming that during crust formation most if not all volcanoes were explosive and that is false as the quoted text you posted confirms:
Not splitting hairs at all. There is evidence of violent submarine explosions in places where scientists believed there never could be due to depth and pressure. That discovery has changed the way ocean scientists look at volcanic activity on the ocean floor.
You claimed that basalt eruptions at the mid ocean ridges are not explosive, and I demonstrated that they can be and have been. I am not saying anything about snowball earth or whether the authors conclusions are valid or not. Simply pointing out that your conclusion about basaltic eruptions, was not.
Research by the OU many years ago discounted the Snowball Earth theory due to drop stones found in sediments of the correct age. Drop stones fall from icebergs as they melt.
There still would have been icebergs in a snow ball earth scenario.
For anyone interested in Snowball Earth some detailed discussion here with the general conclusion of don’t know how/why it started and don’t know how/why it ended..
http://geosci.uchicago.edu/~dkoll/PAPERS/annurev-earth-040809-152447.pdf
I suspect that things were more complicated than Gernon suggests.
For example if the break up of Rodinia caused planet wide glaciation why did the break up of other supercontinents, for instance Pangea, not lead to similar massive glaciation ?
Rodinia wasn’t in the same geographical position as Pangaea. It might be more accurate to state, as per Bill Illis above, that the formation of Rodinia may have facilitated the creation of a Snowball Earth, while its breakup may have hastened exit from the global grasp of ice. However, there were apparently two snowballs or slushballs during the Cryogenian, ie the Sturtian and Marinoan.
Also, Pierrehumbert, et al, rely IMO far too heavily on CO2 and CH4 in explaining global glaciations.
Sorry, don’t have time to read, but. Has the paper calculated 1) where Earth/our Solar System had “orbited/traveled” in the Milky Way galaxy (Svensmark) and 2) where the continents were located? Absolute musts (probably among others — including the science of CO2) — if there is to be any science.
These guys invoke weathering drawdown and volcanic production of CO2 in ad hoc fashion, whichever suits their immediate need. They don’t consider the amount of ridge volcanism that would be required push all the continents into a pile at the south pole and keep them there. They consider only the weathering of the mountains resulting from the collisions to plunge the planet into snowball, but then conveniently invoke the ridges again to burn us out of it.
If a drop in CO2 levels caused worldwide glaciation, why do we not have world wide glaciation today, despite the fact that CO2 levels are lower today than they were then?
The breakup of Pangea caused a warming spike and the end-Triassic extinction event.
So why would a Rodinia breakup cause cooling?
Its all too familiar, simply more “CO2 is the answer now what’s the question”.
The reduction of CO2 would be the result of glaciation why would anyone claim otherwise? Volcnoes could cause a glaciation regardless of the amount of CO2 in the atmosphere by way of Gay-Lussac’s law – which simply states that pressure is inversely proportional to temperature… I find it difficult to believe there are scientists who think that CO2 does not conform to the environmental temperature conditions that it is found in… the other thing I was thinking about is, what could cause a large up tick in volcanic activity? Some kind of core movement caused by a shifting polar field??
I believe that submarine vulcanism probably does play a role in ice formation that results in the growth of continental glaciers. Somehow water is transported from the oceans to the land masses where it remains locked in a frozen state. The ocean levels drop anywhere from 350 to 500 feet during glacial epochs. Something has to put that extraordinary amount of water into the atmosphere where it can become ice crystals that are deposited on land over time.
El Nino events are a good example of how it might occur. Look at the huge amounts of snow being deposited in the Sierra Nevada mountains presently. During El Ninos, what causes the water to warm in the Pacific? Do we have a good explanation for that?
The other part of the theory, where CO2 warms the atmosphere sufficiently for melting to begin, seems a bit of a stretch, however.
How could you design a planet at Earth distance from the Sun so entire planet is covered by ice?
It seems the easiest way is to put dust at Sun/Earth L-1. Or stop the sunlight from reaching Earth.
The L-1 has larger volume of space than compared to Earth.
If you had .1 of gram per cubic meter, a column 1 by 1 meter by 1 km has 100 grams of dust, and if
10,000 km, it’s 1 million grams of dust or 1000 kg. And 2500 kg is 1 cubic meters of solid dust and 10 cm deep is 250 kg, or 1000 is equal to 40 cm deep by meter square. So if had density of .1 of gram per cubic meter filling entire zone of L-1 that would block nearly all the sunlight and make such planet colder than Pluto. Or one could say that one needs less then .1 grams of dust per cubic meter.
And volume of say 20,000 km sphere is 4.19×10^21 cubic meters. Which .1 gram per cubic meter
is 4.19×10^17 kg. In comparison our Moon 7.3 ×10^22 kg. Or our Moon is more than 5 orders more massive. Or Mars moon, Phobos, is 1 x 10^16 kg, or this dust would be mass of about 40 Phobos moons. So one has so much dust that it’s a problem [in long term] is terms of have too much gravity
to remain as dust, but probably don’t need a planet colder than Pluto.
Let’s say instead you want it as cold as the dwarf planet Ceres [much warmer than Pluto] and say after sunlight goes thru the atmosphere it’s 100 watts per square meter with clear skies and sun at zenith.
This has sunlight which is strong enough to evaporate ice and one would have some water vapor in an atmosphere. So this might be around .01 grams per cubic meter, 4 cm thick, or about 4 Phobos moons of mass of dust. And it seems this would give you planet completely covered in ice.
But let’s use even less dust, so that one gets 500 watts per square meter at the surface when sun is at zenith, and we have something like Mars rather than Ceres. Now, it’s something like Mars but it also quite different as we roughly assuming it’s earth size, has earth atmosphere, has the Moon and is tilted and rotating like Earth [though rotation and tilt would like Mars].
With a denser atmosphere one could similar amount sunlight when sun is at zenith, but with earth one has less sunlight reaching the surface when sun is not at zenith. Or summertime on Earth is more similar to summertime on Mars, but Spring, Fall, and Winter have more of a difference.
Or one could also say that is more similar if just comparing earth and mars tropics, and much greater difference if comparing their Temperate and Polar Zones.
So with earth at equator at noon in equinox, and clear skies one gets 500 watts per square meter, and with Mars equator with same conditions it’s +500 watts. And with Earth 3 hours before and after zenith it’s about 400 watts and with Mars it’s still +500 watts.And when at 4 hour +/- of zenith and level ground, the sunlight is being spread over about twice as much area, so instead 400 it’s about 200 watts per square reaching surface. Plus in addition sunlight is passing thru more atmosphere when at 30 degree angle plus the atmosphere is reflecting more sunlight- and the latter aspects are different than Mars.
So similar when sun is at zenith and becomes more dissimilar as sun moves significantly away from zenith but most similar at equator or tropics.
Now were Earth to get 500 watts per square meter at zenith at it’s surface, I have little doubt that outside
the tropics is going to be a frozen Hell- on Earth [but btw, less so on Mars] but even under such an extreme change I am uncertain about the tropics. Or were there a huge wall at Tropic of Cancer and Capricorn, it seems average temperature could be well above freezing. Now without the large walls the factor of greatest uncertainty seems to be evaporation heat loss from the tropics [or biggest way of transporting heat from the tropics via ocean circulation would blocked by rest of the planet being a frozen Hell [ocean would be frozen in these regions]. And assuming this evaporation at any rate, and given enough time- thousands of years, all the water could migrate poleward where it remains frozen
Or we could have started point of completely frozen earth and then turn on the Sun and evenually all water would be evaporate from the tropics.
Or other thing to start with is the tropics completely covered with land. Tropics is 40% surface area of Earth, and total land area is 30% and currently 80% of earth’s tropics is ocean. But were we to have 40%
land area and all of it in the tropics, one gets about the same thing- blocks heated tropical ocean [because there isn’t one] and prevents a lot of evaporation from the tropics from transporting to rest of the world.