From Harvard University Science: Scientists find signs of ‘snowball Earth’
Research suggests global glaciation 716.5 million years ago
Steve Bradt
Harvard Staff Writer
Geologists have found evidence that sea ice extended to the equator 716.5 million years ago, bringing new precision to a “snowball Earth” event long suspected of occurring around that time.
Led by scientists at Harvard, the team reports on its work in the latest edition of the journal Science . The new findings — based on an analysis of ancient tropical rocks in remote northwestern Canada — bolster the theory that the planet has, at times in the past, been covered with ice at all latitudes.
“This is the first time that the Sturtian glaciation [the name for that ice age] has been shown to have occurred at tropical latitudes, providing direct evidence that this particular glaciation was a ‘snowball Earth’ event,” said lead author Francis A. Macdonald, an assistant professor in Harvard’s Department of Earth and Planetary Sciences. “Our data also suggests that the Sturtian glaciation lasted a minimum of 5 million years.”
The survival of eukaryotic life — organisms composed of one or more cells, each with a nucleus enclosed by a membrane — throughout this period indicates that sunlight and surface water remained available somewhere on the surface of Earth. The earliest animals arose at roughly the same time, following a major proliferation of eukaryotes.
Even on a snowball Earth, Macdonald said, there would be temperature gradients, and it is likely that ice would be dynamic: flowing, thinning, and forming local patches of open water, providing refuge for life.
“The fossil record suggests that all of the major eukaryotic groups, with the possible exception of animals, existed before the Sturtian glaciation,” Macdonald said. “The questions that arise from this are: If a snowball Earth existed, how did these eukaryotes survive? Moreover, did the Sturtian snowball Earth stimulate evolution and the origin of animals?”
“From an evolutionary perspective,” he added, “it’s not always a bad thing for life on Earth to face severe stress.”
The rocks that Macdonald and his colleagues analyzed in Canada’s Yukon Territory showed glacial deposits and other signs of glaciation, such as striated clasts, ice-rafted debris, and deformation of soft sediments. The scientists were able to determine, based on the magnetism and composition of these rocks, that 716.5 million years ago they were located at sea level in the tropics, at about 10 degrees latitude.
“Because of the high albedo [light reflection] of ice, climate modeling has long predicted that if sea ice were ever to develop within 30 degrees latitude of the equator, the whole ocean would rapidly freeze over,” Macdonald said. “So our result implies quite strongly that ice would have been found at all latitudes during the Sturtian glaciation.”
Scientists don’t know exactly what caused this glaciation or what ended it, but Macdonald says its age of 716.5 million years closely matches the age of a large igneous province stretching more than 930 miles from Alaska to Ellesmere Island in far northeastern Canada. This coincidence could mean the glaciation was either precipitated or terminated by volcanic activity.
Macdonald’s co-authors on the Science paper are research assistant Phoebe A. Cohen; David T. Johnston, assistant professor of earth and planetary sciences; and Daniel P. Schrag, Sturgis Hooper Professor of Geology and Professor of Environmental Science and Engineering, all of Harvard. Other co-authors are Mark D. Schmitz and James L. Crowley of Boise State University; Charles F. Roots of the Geological Survey of Canada; David S. Jones of Washington University in St. Louis; Adam C. Maloof of Princeton University; and Justin V. Strauss.
The work was supported by the Polar Continental Shelf Project and the National Science Foundation’s Geobiology and Environmental Geochemistry Program.
vigilantfish,
Thanks for the heads up.
Interesting.
Interesting that a number of commentators here have laid into this article as if the authors are advocating significant CO2 influences on snowball earth conditions and even more interesting that the authors have made no reference to CO2 influences.
It has been interesting to note the way authors have written papers either purporting to suport the AGW case, if the evidence suggests it is consistent with AGW, or declaring that their study doesn’t actually contradict the AGW theory even though the evidence of their work appears to.
We had a paper here recently in which the authors felt obliged to say that the USA was not the whole world and the data was possibly indicative of a regional anomaly or some such.
As we move forward from climategate it would be interesting to see to what extent authors feel free not to have to make their work seem either to support or not actually contradict AGW.
Is this paper a sign of the times?
Heh, I love the creationism. Tough to have any understanding of climate, geology, or the bulk of science that involves time if you believe in world wide floods and creationism.
Thanks for the chuckles.
“This is the first time that the Sturtian glaciation [the name for that ice age] has been shown to have occurred at tropical latitudes, providing direct evidence that this particular glaciation was a ‘snowball Earth’ event,”
Fascinating!
Plus, I read several years ago that, prior to 550 million years ago, on three or four occasions, the Earth was so hot that all the water vaporized. (Or perhaps this was just a theory …?)
I’m off to try Kwik’s innovation of “grant-forcing”. How’s this for an intro:
“Carbon Dioxide is eeeevil. We must stomp it out ruthlessly …”
<<>>
I will recommend something else that you should love reading. It is the book, The Chilling Stars, by Svensmark and Calder. They describe a new theory that explains our climate history far better than any other factor. The theory came from the observation that showed that cosmic rays play a role in cloud creation. You can read a general explanation if you hit the download button at the link below.
http://www.scribd.com/doc/338170/svensmark-2007cosmoclimatology
If you like what is in the article I recommend the book very highly. The CRF explains the findings of very diverse disciplines and ties them in together.
It is interesting to note that the CRF theory predicted that there should have been glaciation during the periods in question and explains the faint sun paradox in ways that CO2 levels cannot. If you read the book you will never accept the false arguments from the AGW side again.
Thanks for the thoughtful responses. I am now reading Popper and Kuhn, after your “post normal science” debates of the last few weeks. There is never a shortage of interesting and challenging subjects on WUWT. I live in a drained glacial lake bed which is now some of the most productive farm land in the world. We have much more to fear from cooling than from warming.
D. Patterson (14:25:23)
Thanks for the useful info.
There was a theory that a too-close-for-comfort supernova caused the end of Ordovician extinction. Is there any mileage in that still? The Saharan-Andean ice age would seem to be a reasonable candidate by itself.
http://en.wikipedia.org/wiki/Ordovician-Silurian_extinction_event
Monique (18:17:05) :
Before anyone gets too excited over the “Snowball Earth” hypotheses, they should read the following carefully, noting the pros and cons of the evidence being brought forward in the papers.
http://www.palaeos.com/Proterozoic/Paleoproterozoic/Paleoproterozoic.html
phlogiston (20:59:21) :
It is hypothesized that a too nearby Gamma Ray Burst (GRB) would create a nitrous oxide smog as it destroyed the ozone layer. The nitrous oxide would soon rain out as acid rain, but the damage caused by UV-B from the Sun would already extensively damage DNA and temperatures would plummet. There is an interesting article on GRBs and an illustration of the effects upon the Earth. See:
Gamma-Ray Bursts – Putting It All Together
http://astronomyonline.org/cosmology/grbs.asp?cate=cosmology&subcate=grbs
(remove the spurious carriage return after the question mark)
Finding evidence of the GRBs in the geological periods may be a special challenge? Gamma ray traces are already being used extensively in geology to identify rock facies and more. Finding evidence of a particular ET source in the geological record may prove to be difficult. FWIW, the Apollo missions discovered unexpected sources of radiation on the Lunar Farside as they were orbiting above the Lunar surface surveying it with photography and a variety of instruments. I don’t recall the details now, but it does highlight how daunting a task it may prove to be to isolate a particular signal for GRBs.
jim (20:24:45) :
For another and different viewpoint on how the paleomaps should look, see also:
Regional Paleogeographic Views of Earth History
http://jan.ucc.nau.edu/~rcb7/globaltext.html
<<>>
This makes no sense. Ozone is created when ultraviolet radiation hits oxygen molecules and causes them to split into two free oxygen atoms, which then combine with O2 to form O3. The ozone layer is constantly being destroyed and replenished so any effect due to a temporary nitrous oxide formation would be limited.
Use a search engine with the search terms “ozone layer” “and “nitrous oxide”, but be careful to stand back when the results come tumbling out. Everyone in the green community from the IPCC, EPA, UK Environment Agency, WWF, Greepeace, BBC, NPR, and so much more flood the Internet and mainstream news media with reports about the dangers of NO(x) emissions destroying the Ozone Layer.
See for example:
In reply to Steve Keohane,
There is apparently no “missing link” between vegetation and crude oil, therefore it appears to be highly unlikely that crude oil comes from vegetation or animals or whatever.
There are 2 possibilities:
There was a truly bizzare event millions or even billions of years ago that caused the formation of “fossil fuels” and then stopped, and therefore the supply of such fuels is finite;
or
“Fossil fuel” production has nothing to do with decomposition of organic matter, and is an on-going process, but we are unsure of the rate at which the process happens, so we don’t really know if we are using it up faster than it is being produced or not.
I realize that limiting it to 2 possibilities is overly simplistic, but it would certainly SEEM that if oil came from some process of organic decomposition we would at least be able to see evidence of the process happening or be able to duplicate the process in a laboratory setting. As far as I know, they can (on a very small scale) duplicate abiogenic oil formation in a laboratory setting, but I have never seen anything on biogenic oil formation (if there even is such a thing) being duplicated in a laboratory setting. I am sure that someone will correct me if that is a wrong impression.
D. Patterson,
The study talks about N2O, and then your equations only show NO and NO2, neither of which are N2O. How would N2O behave?
I know that near ground level, organic compounds and NO/NO2 (also known as NOy) are thought to be precursors of OZONE FORMATION (not destruction).
So, is the EPA claiming that NO/NO2 simultaneously creates ozone near ground level while also destroying it higher up because the mechanisms are somehow different at different levels of the atmosphere?
Google “Ozone Precursors” to see the proposed mechanisms for ozone formation involving organic chemicals and oxides of nitrogen… seems to perfectly contradict the destructive pathways shown in your post….
PeterB in Indainapolis (10:13:06) :
Keep in mind that I am not proposing, defending, or critiquing the information coming from those sources. My post was “reporting” the sources which are being used by the named scientists to hypothesize the effect of a local hypernova on the proposed mass extinction events upon the Earth. Since the proposed gamma ray conversion of nitrogen compounds in the upper atmosphere are alleged to produce NO(x) catalysts that are destructive with respect to the Ozone Layer, the mainstream media has been prolific in linking the story to the alleged effects of similar air pollution sources. Since this involves the IPCC, UK government, US government, Greepeace, WWF, and the other usual suspects, the hypernova link to a proposed Snowball Earth has brought us full circle back to the IPCC et al. This appears to open multiple issues needing further investigation. The role of the nitrogen compounds can be expected to become yet more featured articles on WUWT (smile).
Personally, I haven’t gotten past the first step to address the cationics. I still want to see the proposed mechanisms for the gamma rays altering the compounds of nitrogen into laughing gas and so forth. Now, I’m not saying they do or don’t. Its only a matter of the publications not going into such details….
PeterB in Indainapolis (10:13:06) :
Note, you may find it worthwhile to look more closely at the two cited sources. I’ll let you draw your own conclusions, but the biographies and wide assortmnt of articles, news stories, and other information may prove to be very revealing for you. Search on their “surname” and “ozone” to find these sources. There are stories their awards such as the Nobel Prize, and stories about their activities in the environmental movements. For example:
ESA History
http://www.esa.int/SPECIALS/Space_Year_2007/SEM8IE9RR1F_0.html
Paul Josef Crutzen (1933)
Crutzen was unable to finance a university education and his grades were not good enough for a scholarship.
http://www.uu.nl/EN/research/halloffame/nobelprizewinners/pauljosefcrutzen/Pages/default.aspx
Paul J. Crutzen (1933-). “The influence of nitrogen oxides on the atmospheric ozone content”, Quarterly Journal of the Royal Meteorological Society 96, 320-325 (1970). (Manuscript received 5 November 1969, communicated by Dr. C. D. Walshaw)
http://web.lemoyne.edu/~giunta/crutzen.html
Martin, Brian. The Bias of Science. Canberra: Society for Social Responsibility in Science (ACT), 1979. Part II: Pushing of arguments in the work of Johnston and of Goldsmith et al. [pp. 25-36]; Chapter 1: Technical assumptions; Chapter 2: Selective use of evidence; Chapter 3: Selective use of results; Chapter 4: Method of referring to alternative arguments.
https://www.uow.edu.au/~bmartin/pubs/79bias/part2.html
D. Patterson (11:30:28)
Presumably a big / close enough super / hypernova would not necessarily need an intermediary like NO to cause extinctions – direct ionising effects on organisms would occur at high enough levels. The initial gammas might be very low LET due to high energy but by spallation would cause a cascade of lower energy more ionising particles and photons. But I guess the geologic record would show this clearly if such a high gamma (and derived) dose had been delivered.
D. Patterson (11:30:28)
Sorry – not spallation (wrong process) just Compton scattering and other interactions causing a cascade of secondary (delta) particles.
I think Prf Paul Josef Crutzen is the man who thinks we need to use rockets and artillery to load up the upper atmosphere with sulphur to counter GW, an idea that morphed, in other hands – the “eco-engineers”, into the idea of artificial volcanoes….
http://www.infowars.com/the-government-is-already-geo-engineering-the-environment/
Moon craters.
I was remembering the first maps of the far side, which did not show as much detail as is availible today.
My error.
Some of the discussion of the suspected GRB role in the Ordovician and other ice age and extinction events sees a more complex explanation that includes cosmic rays bringing about spallation in addition to the various effects of the gamma rays.
Discussion of the consequences of a GRB tends to focus mostly upon the production of NO(x) compounds in the Ozone Layer, because the effects of direct irradiation of lifeforms are limited to only the one side of the Earth facing the GRB and only the the exposed terrestrial and pelagic environments. By contrast, any global cooling caused by GRB ionizing and dissociating the nitrogen and oxygen compounds destructive of the Ozone are global in their effect upon lifeforms and must affect the whole Earth.
With respect to evaluations of the Snowball Earth scenarios of the Archean and Proterozoic Eons, the effects of a GRB on lifeforms are minimal because macroscopic lifeforms had not yet colonized the terrestrial landscapes. Since the effects of direct radiation are attenuated by the atmosphere and the upper few meters of the hydrosphere’s marine environment in the hemisphere facing the GRB, the other global effects become more important to the consideration of global cooling events. To the extent a GRB could have any contributing effect upon triggering global cooling and an ice age, any effects such as proposed NO(x) destruction of the Ozone Layer and reduced insolation tend to be the focus of so many investigations.
Now its a question of whether or not and to what degree do the works of the cited authors of the NO(x) hypotheses withstand scientific scrutiny versus environmental advocacy in the guise of science?
D. Patterson (10:22:52)
Thanks.
In reply to D. Patterson (06:39:37) :
I think that you are missing the point. I claimed that your statement, “The nitrous oxide would soon rain out as acid rain, but the damage caused by UV-B from the Sun would already extensively damage DNA and temperatures would plummet,” did not make sense because you are not accounting for ozone formation. Ozone is generated by ultraviolet radiation. As high energy ultraviolet photons react with a oxygen molecules in the atmosphere they cause each molecule to break into two oxygen atoms. Those atoms react with other oxygen molecules to make ozone.
What this means is that the nitrous oxides would not have the same impact that you are claiming because ozone formation is self regulating. This is why we see a reduction in ozone concentrations during the winter; while ozone destruction continues, there is less ultraviolet radiation to create ozone. That reverses in the summer when the greater intensity creates more ozone.