Snowball Earth

There is a theory called the "Snowball Earth" that I think leads to some serious problems for the young earther. Let's take a look, shall we.

For decades, it has been recognized that there was evidence of worldwide glaciation in the Neoproterozoic era (ending about 543 million years ago). Glacial deposits have been found nearly worldwide from this time. One difficulty in making the leap to global glaciation was that it needed to be ruled out that the deposits could have been formed when the landmass was far from its current location and that the glacial deposits could be local and due to the land being at high latitude at the time.

What was needed were deposits that had convincing data that they were formed at tropical latitudes. In the 1960's, Harland found glacial deposits that showed indication of being formed in the tropics due to the association of the deposits with certain sedimentary strata normally formed at low latitudes. This was a start.

"The Great Infra-Cambrian Glaciation," Harland and Rudwick, Scientific American, Vol. 211, No.2, pages 28-36, Feb. 1964.

Later, Kirschvink found deposits that were even more convincing. The first step was to test the rocks with a method called natural remnant magnetization (NRM). With NRM, you measure the remnant magnetic field through the deposits in question. If they formed near the poles, the magnetic field lines will tend to run up and down. The lines will become oriented more and more horizontally the closer you get to the equator. You must also make many many measurments of different rocks. What he found was that the sedimentary deposits from the glaciers were formed in the tropics. The other crucial step was to establish that they were formed at sea level. This is important since even today, some glaciers exists at high altitude at low latitude. The deposits were associated with deposits that were tidal in nature and therefore had formed near sea level.

"Late Proterozoic Low-Latitude Global Glaciation: The Snowball Earth," Kirschvink, The Proterozoic Biosphere, Cambridge University Press, Cambridge, pages 51-52, 1992.

To look at the other evidence for the Snowball Earth, we need to consider what the effects of a global covering in ice would be.

With most of the surface water of the earth covered in ice, gas exchange between the ocean and the atmosphere would cease. The ocean would largely become anoxic, that is very low in oxygen. This in turn would change the solubility or iron in the water. Oxidized iron is rather insoluble while reduced iron is more soluble in water. The anoxic water would allow for a buildup of iron in the oceans. When the ice was removed, the sudden influx of oxygen into the oceans would cause the iron to rapidly fall out of solution. And indeed we find that banded iron formations (BIF) from the Neoproterozoic era are associated with the glacial deposits.

With the continents covered in ice, the normal mechanisms for removing CO2 from the atmosphere would stop. Typically, small amounts of CO2 are dissolved in rainwater. This reacts with the rocks of the continents and geologically locks up the CO2. With the rocks covered in ice, the CO2 from geological sources would continue to pour into the atmosphere and build up.

During the Snowball Earth, this CO2 built up in the atmosphere until the global warming effect was great enough to melt the ice and send the earth into the hothouse. The level of CO2 calculated to be needed to end the global glaciation is about 12% of the atmosphere. Once this was achieved, rapid warming would melt the ice and cause a rapid warmup in the earth's temperature, much warmer than today even. Estimates of sea surface temperatures are about 120 F. All this atmospheric CO2 would also be rapidly removed from the atmosphere and rapidly deposited over much of the world.

And we see just this in the rocks. These worldwide glacial deposits are covered in thick cap dolostones as would be expected if large amounts of CO2 were nbeing removed. These dolostones also preserve another record of the expected warming. The warm waters would drive extreme weather. High levels of rainfall and glacial melt combines with the fractured and groung rocks from the glaciers would lead to rapid erosion of the land. The higher levels of the cap dolostones are mixed with clays. The dolostones also preserve features such as crystal fans and gas escape tubes that indicate formation by precipitation from water saturated with carbonates.

There is an even more curious feature of the layers. The CO2 outagssed from volcanoes contains about 1% C13 and the remainder C12. However, plants fix C12 at a higher rate than C13. By looking at the ratio of C12 to C13 in deposits, it is possible to tell how much of the carbon was removed through organic processes and how much through non-organic processes. The ratios just below the glacial deposits show ratios that indicate that about half of the carbon deposited was from organic sources. (Today that number is about 25%.) But in the glacial deposits and the cap dolostones, the ratio changes to essentially that of the volcanic gasses showing that the carbon being removed was almost all through non-organic processes. The ratios then return to normal. This is to be expected. With the earth covered in ice, biological activity would decrease tremendously. Once the ice started to melt, even though biology would be expected to take off in the warm waters, the rapid geological processes would have swamped any biological effects.

One of the strongest oppositions to the theory came from biology. Just how could life that required photosynthesis have survived the Snowball. Recently life has been found under thick layers of ice in the antarctic that gives clues about how life could have survived. Ice in such regions has also been shown to transmit enough light for photosynthesis to much deeper layers that previously thought. Combine this with local oases such as undersea vents, hot springs, and areas of open water and life manages to survive the snowball.

"A Neoproterozoic Snowball Earth," Hoffman, Kaufman, Halverson, Schrag, Science, Vol. 281, pages 1342-1346, August 28, 1998.

The Snowball Earth theory seems to be the only one that can explain the tropical glacial deposits, the cap dolostones, the paradox having these two close by implies (extreme cold followed by extreme warmth), the associated BIF, and the excursions of the carbon isotopes through this period.

The obvious answer for YEers is to invoke the flood. But this has several problems. How does a flood result in glacial deposits? How does a flood result in such thich caps of carbonates? (Where did all the CO2 come from?) How do you make the ocean anoxic in order to dissolve all that iron with the oceans and atmosphere in continuous contact and exchange? If the oceans were anoxic, how did the fish survive? How are the carbon isotope anomolies explained?

Provided that reasonable solutions can be reached for all of those, there remain two more. First is that there are at least four such events recorded worldwide. How do you work all of these into one event? Second, life on the surface could not survive 12% of the atmosphere as CO2. Respiration would be impossible. Your lungs would be unable to discharge waste gas from your lungs. Just not enough driving force to get the gasses out of the blood by overcoming the partial pressure.

 

I think I have the evidence a lot closer to what I posted than the response.

Just skipping to the conclusion.

"1. The rocks in the diamictites show very sharp angles and rough sides and more roundedness on others, indicating they have been rolled by water. Glaciers are very slow moving, and tend to polish off the rocks they move. "

Which way to look at this?

These results have been published. What is it that made them think these were dropstones to begin with? I am not a geologists but they are. I am guessing they know what one looks like and if not that would have been the first objection of peer review if all this was based on such a simple mistake. And we are not talking about what was at the time a widely held theory. It was, may still be, controversial and people were looking for holes in it. Surely something so simple did not slip through.

Just how quickly do you think rocks would be made round in rolling water?

I would tend to think that the grinding of a glacier could produce sharp edges where two sides that were ground meet. The rough and rounded edges were then not exposed to the grinding.

If they were rounded by rolling in water, should not the whole rock be rounded? This would seem to be even less likely to be able to round AND leave rough and sharp edges.

Anecdotally, on a recent trip to the Tetons, a large fraction of the rocks in the glacial moraigne I saw had been rounded.

"2. The presence of large stromatololites. Current stromatolite activity can be seen at Hamelin Pool in Western Australia. These stromatolites form in warm water."

Yes and there were periods of warmth between the ice periods. Periods of extreme warmth.

Not sure about this one but... Watched a special on Lake Vostok a few months ago. I thought they found some stromatolites growing on the underside of the ice.

"3. The carbonate cap (limestone). The formation of a carbonate cap requires warm greenhouse conditions. The Brighton limestone is right in the middle of the "Snowball Earth" strata. The only way the Snowball Earth advocates can explain this is via a series of sudden changes in the earth's atmosphere several times during this period of presumed glacial activity."

And...?

It would be unavoidable to have such greenhouse conditions following the period of ice. The contribution of CO2 to the atmosphere from geologic processes would continue while weathering would be unable to remove it. The intervening periods of heat would be necessary a consequence.

"4. The obvious indication of liquid water rather than ice in some of the layering."

The dropstones were dropped from ice, through water, into the sediments. So, yes, they should show some evidence of water. They wouldn't be dropstones if they were not dropped by rafts of ice.

"2. Paleomagnetic data indicating that a number of rocks in South Australia originated at or near the equator. What else besides glaciers could have dragged these rocks so far?"

THey were dragged there by plate techtonics. The paleomagnetic data shows that the tillites themselves, not the dropstones, originated at the equator.

From the first page.

"It would have to be the entire earth, for if there were glaciers at the equator which could recede to the south, carrying equatorial rocks to Australia, then there must have been glaciers everywhere. What else besides glaciers could have done this? "

Covered above. The rocks were not dragged there from the equator. They sedimentary rocks themselves formed at the equator and were transported whole by plates.

The attempt at an alternate explanation does not really address the evidence for the Snowball Earth. It tries to say that a few things are incompatible which in reality are compatible and are even an important part of the theory.

The alternate explanation does not explain where the thick layers of carbonates could have originated. It does not explain why the carbonate caps only begin having clays and such mixed in at higher layers. If you use a global flood explanation, the whole carbonate cap layer should have been heavily mixed with sediments.

It does not explain the peculiar excursion in the carbon isotope ratios.

It does not explain how the oceans could have become anoxic, filled with reduced iron, and then formed the banded iron deposits.

It does little to give an alternate to the theory to better explain the observations and does little to give us factual objections to the theory.

 

I paid attention, but the response made objections that were not objections to the actual theory and did not attempt to better explain any of the details that it explains so well.

I also forgot to mention that there was not an explanation of why there are at least four such layers from one big flood.

 

I have a response, but first a question.

What exactly do you mean when you say "the second layer above the carbon rich layer (which is attributed to snowball earth)?" I have yet to notice any references to such a carbon rich layer in anything I have read. Could you please provide some references for this? The context seems to indicate that you mean the carbonate layer itself. I really hope not. That generates some problems. The first is do you have a chemical method to turn all that buried organic carbon into carbonates? But the more critical question is to ask why the carbonates have a carnon isotope ration that indicates geologic and not organic origins for the carbon?

"Just for the heck of it, here:

http://www.geology.ucdavis.edu/~cowen/HistoryofLife/CH04.html

http://www.nature.com/news/1998/981210/pf/981210-1_pf.html

Also, in The Australian Geologist, no. 117, there is an article by Australian geologist George Williams Ph.D. in and professor of, geology at Adelaide University, entitled "Snowball Earth -- A Snowball's Chance" in which he presents a very complete refutation of the Snowball earth idea. In it, he lists ten major points showing the snowball earth scenario disagrees with the evidence."

For those that are interested, the full citation for Helen's reference above is

Williams, G. & Schmidt, P., 2000. Proterozoic equatorial glaciation: has "Snowball Earth" a snowball's chance? Australian Geologist, 117, 21-25.

There is a refutation of it from the authors at

http://www.people.fas.harvard.edu/~maloof/bigtilt.pdf

But we will return to that in a moment.

The first answer is that these references do absolutely nothing to advance your case. You cannot simply say that this one old earth idea is wrong because these other old earth references show something different. When advancing a young earth position it is not suficient to merely substitute one old earth theory for another. I could easily concede the point here and ask why it is that the old earth theory you advanced is wrong and why you advanced a theory that you do not accept. But I do not have to do that as the references do not adequately address the subject.

The first reference is to an alterantive called the Slushball earth. In it, the earth oceans are not completely frozen; a fraction remains ice free. The article deals largely with biology. A more direct link can be found here. http://www.geology.ucdavis.edu/~cowen/HistoryofLife/slushball.html It is an interesting idea and it can explain some of the evidence for the Snowball earth. Indeed it is a similar idea though with some important differences. But it most certainly not a global flood! It is worth a read to those interested.

The second reference seeks to explain the evidence by a shift in the angle of inclination of earth's rotational axis. Even the author or the article claims that "this research will not be greeted with approbation everywhere, and runs counter to other evidence that obliquity underwent no massive shifts." This high tilt theory runs into other problems. There does not seem to be an acceptable mechanism for producing such a rapid shift in obliquity. It would be unable to produce the global glaciation. It is not clear that it would even be able to produce the most important part, the low latitude glaciation. The high obliquity would cause very cold winters at the equators, but the summers would be just as sun drenched as today wit hte sun passing directly overhead. Cool summers seem to be even more important than cold winters in producing glaciers. Hot summers eat away at the ice through ablation. Without covering the earth in ice, it also fails to provide a mechanism for the banded iron formations. That is enough on that since it still, too, is not a global flood.

The final mention was of a paper giving ten specific problems with the snowball earth. The rebuttal to that has been linked to above. It seems that most of the "problems" were due to a lack of understanding of the theory. I'll just quote the introduction here, the reader is free to go read the whole paper. It is only about 8 pages long.

"Barry looked at UTE's response and mostly just smiled..."

Smile if you wish but I do not yet see discussion of the evidence I presented. Where is the explanation for the carbonates and the banded iron and the carbon isotope ratios for a start?

"...but he did mention that in South Australia there is the interesting phenomenon of the Whyalla Sandstone which phases into the diamictite which is supposedly evidence of snowball earth. The trouble is that the Whyalla Sandstone is a windblown sand -- and a LOT of it! So to have windblown stand does not agree with an earth totally covered in ice. Both cannot exist at the same time."

Except that the sandstone seems to be an unconformity as near as I can find out about it. Here is one mention. http://www.pir.sa.gov.au/pages/minerals/commodity/cobalt.htm:sectID=245&tempID=7 "Mineralisation is principally in the upper surface of a palaeo-permafrost brecciated sandstone of the pre-Adelaidean Pandurra Formation, which is unconformably overlain by Adelaidean Whyalla Sandstone." Emphasis added.

So they did not have to exist at the same time.

"Another point Barry makes here, reading this, is that the diamictite, which is meant to be evidence of ice age activity, has a dolomitic cement around all the debris cobbles and boulders, and dolomites only form in warm water."

I'll use for first reference above for one answer. It describes how methane released and trapped under the ice could have contributed to the carbonates. So there is one answer. Another answer would be that they formed at the boundary between the cold and hot periods. Or, dolomite formation can be enhanced by high alkalinity in sea water.

"About the 'four layers.' Many geologist around the earth are now saying that the four layers are only two layers and that our dating procedures are at fault here."

Really?

"New constraints on the ages of Neoproterozoic glaciations in south China," Zhou et al, Geology: Vol. 32, No. 5, pp. 437–440.

Published this year. "The most complete Neoproterozoic successions in south China contain three diamictite intervals in the Changan, Tiesiao, and Nantuo Formations."

In an press article...

http://www.sciencedaily.com/releases/2004/04/040421234349.htm

"However this second layer of diamictites or drop stones appears to be much more from mudslide activity as the result of earth movements."

And in the rebuttal from Hoffman and Maloof linked above, they say that they expect and observe submarine slumps in connection with the snowball earth.

 

Bump.

Anyone else want to make a go at explaining the data?

 

This subject came up in another thread and it was requested that that thread not be taken off topic. I will honor that request and bump this thread instead to allow the discussion to continue.

Helen posted that "3. Snowball earth is a desperate assumption by a few geologists to account for what is actually the Flood layer of Noah. The diamictite layer under the carbon rich layer is in a cement matrix which required warm water to form. That's hard to account for when stuff is supposedly frozen!"

I responded.

Would like an answer as to a YE explanation that fits all of the data and an answer to the outstanding question of whether the cap dolostones are supposed to be the oft mentioned carbon rich layer and if not, which layer is.

 

Anyone yet have a YE explanation for the layers that are associated with the Snowball Earth hypothesis?

 

Nice parody. That somehow sounds familar...

 

Are the cap dolostones supposed to be the oft mentioned carbon rich layer and if not, which layer is?

 

And again, are the cap dolostones supposed to be the oft mentioned carbon rich layer and if not, which layer is?

----------------------

And some other outstanding questions...

If so, how do you account for the evidence which shows this layer to be inorganic in nature? One, as mentioned, is that there is an excursion in the ratio of carbon isotopes that indicate a non-organic origin for the carbon in the dolostones. Second, the dolostones also preserve features such as crystal fans and gas escape tubes that indicate formation by precipitation from water saturated with carbonates, not an organic origin.

And how do you explain the data including the multiple layers? There are at least three such layers and perhaps four.

"New constraints on the ages of Neoproterozoic glaciations in south China," Zhou et al, Geology: Vol. 32, No. 5, pp. 437–440.

Published last year. "The most complete Neoproterozoic successions in south China contain three diamictite intervals in the Changan, Tiesiao, and Nantuo Formations."