Study finds ‘Snowball Earth’ event gave rise to oxygen based life

Study shows planet’s atmospheric oxygen rose through glaciers, climate swung so extremely that the polar ice caps extended to the equator and the Earth was a snowball

snowball
From the UNIVERSITY OF WYOMING

A University of Wyoming researcher contributed to a paper that determined a “Snowball Earth” event actually took place 100 million years earlier than previously projected, and a rise in the planet’s oxidation resulted from a number of different continents — including what is now Wyoming — that were once connected.

“Isotopic dating of the Ongeluk large igneous province, South Africa, revealed that the first Paleoproterozoic global glaciation and the first significant step change in atmospheric oxygenation likely occurred between 2,460 and 2,426 million years ago, approximately 100 million years earlier than previous estimates,” says Kevin Chamberlain, a UW research professor in the Department of Geology and Geophysics. “And the rise of atmospheric oxygen was not monotonic but, instead, was characterized by significant oscillations before irreversible oxygenation of the atmosphere 2,250 million years ago.”

Chamberlain is the second author of a paper, titled “Timing and Tempo of the Great Oxidation Event,” which appears in the Feb. 6 (today’s) issue of the Proceedings of the National Academy of Sciences (PNAS). The journal is one of the world’s most prestigious multidisciplinary scientific serials, with coverage spanning the biological, physical and social sciences.

Ashley Gumsley, a doctoral student at Lund University in Lund, Sweden, is the paper’s lead author. Other contributors were from the Geological Survey of Canada in Ottawa; Swedish Museum of Natural History; University of Johannesburg, South Africa; and the University of California-Riverside.

The research relates to a period in Earth’s history about 2.45 billion years ago, when climate swung so extremely that the polar ice caps extended to the equator and the Earth was a snowball, and the atmosphere was largely isolated from the hydrosphere, Chamberlain says. Recovery from this Snowball Earth led to the first and largest, rapid rise in oxygen content in the atmosphere, known as the Great Oxygenation Event (GOE), setting the stage for the dominance of aerobic life, he says.

A later, and better known, Snowball Earth period occurred at about 700 million years ago, and led to multicellular life in the Cambrian period, Chamberlain says. The events show there was not one event, but an oscillation of oxygen over time that led to the Earth’s conditions today.

“So, both Snowball Earth periods had extreme impacts on the development of life,” he says. “It helps us understand the evolution of Earth and Earth’s atmosphere, and evolution of life, for that matter.”

Chamberlain’s contribution focuses on igneous rocks exposed in South Africa that record the existence of equatorial glaciers and contain chemical indicators for the rise of atmospheric oxygen. Chamberlain’s in situ method to determine the age of the rocks does not require removing baddeleyite crystals from the rock. This process allows for analysis of key samples with smaller crystals than previously allowed. Using a mass spectrometer, the age of the rocks is determined by measuring the buildup of lead from the radioactive decay of uranium, he says.

“The basic story had been worked out earlier by others, but our results have significantly refined the timing and duration of the ‘event,’ which is more of a transition actually,” Chamberlain explains. “With all the discussion of climate change in the present day, understanding how Earth responded and the effects on the atmosphere in the past may help us predict the future.”

Chamberlain points to a Wyoming connection in this research. From paleomagnetic data, many of the continents, at the time, including the basement rocks of Wyoming, were all connected into a single, large continent and situated near the equator. Other continents connected included parts of what are now Canada and South Africa. This situation is part of the trigger for the “Snowball Earth” conditions.

“There are glacial deposits exposed in the Medicine Bow Mountains and Sierra Madre that are from this same event,” he says.

These rocks, known as diamictites, have large drop stones that depress very fine-grained mudstone. The large stones dropped from the underside of glacial sheets as they spread out and melted over shallow seas, similar to sediments beneath the Ross sea ice sheet of Antarctica today.

“The fact that these sediments were at the equator at 2.45 billion years ago comes from the paleomagnetic data from associated igneous rocks,” Chamberlain says.

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121 thoughts on “Study finds ‘Snowball Earth’ event gave rise to oxygen based life

  1. many of the continents, at the time, including the basement rocks of Wyoming, were all connected into a single, large continent and situated near the equator.

    The Earth as freezing over seems to deploy the modern continental arrangement.

    Cameras were pretty primitive 2,260 million years ago, and satellites even more so, but couldn’t someone of more recent vintage have produced a time-appropriate illustration?

  2. Fascinating. What would the atmospheric pressure have been in those primordial times? How would those pressures affect precipitation and atmospheric circulation? What was the oceanic salinity then?
    Incidentally, the earth illustration is lacking cloud cover, which would seem necessary to have increasing glaciation.

      • How are you seeing the continental arrangements under all that ice?
        Presumably the first, and smallest earth is the most current time, then farther back as the globe’s get bigger

  3. I had heard about “snowball Earth”, but hadn’t realised that it was more than one event. Nor that it wasn’t as clean-cut as it was described.

  4. Wyoming is an amazing place to visit and there’s a lot more to it than Yellowstone. I have fossils of scallops that I pulled from a place near Medicine Bow at an elevation of nearly 8,000 ft.

    • Yes! Come visit Wyoming. (Not during the total eclipse this year, though.)

      There are all kinds of interesting fossils, Wind River Canyon is awesome—paleo layers are labelled throughout the canyon. If you want to see geology in real life, this is the place. I can’t spend enough time out checking these areas out. It’s living science.

  5. The Snowball Earth event discussed here is the Huronian glaciation of the Siderian and Rhyacian Periods of the Paleoproterozoic Era. It was the oldest and longest known glacial interval.

    Much later, during the Cryogenian Period of the Neoproterozoic Era, there were two more Snowball incidents, the Sturtian and Marinoan.

    • I will not dispute that glaciations favor Oxygen. I will dispute that true snowball condititions ever occurred. You can draw white circles and stuff for visual effect, but where is the EVIDENCE amigo? That Wyoming was supposedly at the equator 2.2bya?

      Apparent polar wander paths degenerate ridiculously before the Phanerozoic. True polar wander is definitely a possible factor. Even in the mid-Phanerozoic, magnetic apparent wander paths would have a microcontinent off the west coast of North America zooming thousands of kilometers south to the Southern Hemisphere, and then reversing field to migrate thousands of kilometers north to take up residence in B.C. as Wrangellia.

      Poco sal, qhi mo sabe.

      • Thank you. Had not seen that.Doubtless you have noticed that Wyoming is not on the equator in this reconstruction.

        We naked apes really don’t know that much, despite our posturing. You have a great mind. Onward.

      • Gymno,

        No, it isn’t. I’m not sure that the authors claim that it was, just that the continents were connected and that the supercontinent was centered of the equator.

        Columbia wasn’t, but Kenorland, the previous supercontinent seems to have been, to include WY:

        Columbia is now thought to have formed after the Snowball Earth episode.

      • Gymno,

        IMO the core of Rodinia is pretty well established based upon mountain-building episodes c. one billion years ago, but the arrangement of outlying cratons is controversial. Orogenic belts shown in green:

        You’re right of course that Columbia, Kenorland and earlier assemblages get increasingly more conjectural, although not without some pretty good evidence.

    • Excerpt from article:

      The research relates to a period in Earth’s history about 2.45 billion years ago, when climate swung so extremely that the polar ice caps extended to the equator and the Earth was a snowball, and the atmosphere was largely isolated from the hydrosphere,

      Don’t forget now, a horrendous amount of ocean water had to have been evaporated from the tropical latitudes and transported to the higher latitudes to create the aforesaid “polar ice cap extensions”. This undoubtedly resulted in a tremendous decrease in sea levels until such time that what remained of the tropical ocean surface simply “froze over” and the Snowball Earth creation process terminated.

      Excerpt from article:

      Chamberlain says. Recovery from this Snowball Earth led to the first and largest, rapid rise in oxygen content in the atmosphere, known as the Great Oxygenation Event (GOE), setting the stage for the dominance of aerobic life, he says.

      OK, but it had to have been a long, long time after said “recovery” began before a sufficient quantity of “meltwater” could refill the ocean basin ….. and then a long, long time before there was a sufficient quantity of ocean water residing “photosynthesizing” plant life that resulted in said Great Oxygenation Event (GOE).

      Excerpt from article:

      A later, and better known, Snowball Earth period occurred at about 700 million years ago, and led to multicellular life in the Cambrian period, Chamberlain says.

      I seriously doubt that the aforenoted Snowball Earth event had anything whatsoever to do with the occurrence of the “Cambrian Explosion”, …….which by the way, …… was a direct result of “horizontal or lateral gene transfers” (LGT) between the different life forms that existed during the per se Cambrian Period.

      “HA”, it should be obvious to most anyone that the only means possible for a Platypus to have evolved was via LGT.

      • HGT had nothing to do with the so-called Cambrian Explosion or the evolution of platypuses.

        The ancestors of all mammals laid eggs. Monotremes just happen to be the only group which still does. They survived in Australia because the only other mammalian group there, marsupials, can’t live in water, because of the joeys in their pouches. While not aquatic like platypuses, echidnas, the other monotreme suborder, do spend a lot of time in the water.

      • So responsith did: Gloateus Maximus February 7, 2017 at 5:09 am

        HGT had nothing to do with the so-called Cambrian Explosion or the evolution of platypuses.

        GMF, and just what is your problem with the following definition/description of the evolutionary events that have been determined to have occurred during the Cambrian Period that began around 541 million years BP, to wit:

        The following excerpted from: https://en.wikipedia.org/wiki/Cambrian_explosion

        The Cambrian explosion or Cambrian radiation was the relatively short evolutionary event, beginning around 541 million years ago in the Cambrian period, during which most major animal phyla appeared, as indicated by the fossil record. Lasting for about the next 20–25 million years, it resulted in the divergence of most modern metazoan phyla. Additionally, the event was accompanied by major diversification of other organisms. Prior to the Cambrian explosion, most organisms were simple, composed of individual cells occasionally organized into colonies. Over the following 70 to 80 million years, the rate of diversification accelerated by an order of magnitude and the diversity of life began to resemble that of today. Almost all the present phyla appeared during this period,

        Gloateus Maximus, do you actually and/or seriously believe that ….. “random gene mutations” within the DNA ……. and/or “natural selection” of pro-creating partners …… is sufficient explanation for the
        major diversification of other organisms, ….. namely the origin and survival of all present day major animal phyla, …… which is attested to by their first appeared in the fossil record.

        IMLO, ……. random gene mutations ….. is neither a logical or intelligent reasoned explanation for the origin of all major animal phyla within a 20–25 million year “window” ,,,,, and then no further major diversification occurring during the next 541 million years.

        GMF, in that you disagree with my claim of HGT ….. then I have to assume that you have a better explanation for the animal diversity arising during the Cambrian Period, ……. right

      • Samuel,

        Random gene mutations happen all the time, although more cosmic rays and other environmental factors can increase mutation rates.

        What causes evolution to occur more rapidly or slowly is processes like natural selection or reproductive isolation. In the case of the Cambrian, selection worked rapidly because of innovations such as vision, predation and the consequent development of calcareous shells and other hard body parts. Not to mention more oxygen.

        But the novelty of the Cambrian has been shown to be less sudden than first thought in the 19th century. Phyla previously assumed to have arisen then are now known to have existed in the Precambrian, specifically the Ediacaran Period. Until the 1950s, it was believed that there were no Precambrian fossils, but every year since then has brought more and older discoveries. It’s just that even the macroscopic fossils are small and mainly soft body part impressions.

        That calcareous body parts evolved to defend againsst predators should not surprise anyone. Even sponges have spicules. The oldest fossil sponges date from over 600 Ma, ie about 60 million years before the Cambrian. Tjhey are already recognizable, but tiny, so animal evolution must have started well before that time, as molecular clocks indicate.

        Thus, no need to posit HGT to explain the rapid evolution of animals in the Cambrian.

      • Random gene mutations happen all the time,

        Maximus, …… “yup”, noninfrequently all the time, …. and which are the primary cause of most every type of human cancer.

        Gloateus Maximus, this is not my first rodeo, ya know. I am somewhat learned and/or familiar with most everything ”evolutionary” that you were, per se, mimicking, in your above posted verbiage. I earned my Degrees in both the Biological and Physical Sciences more than 50 years ago and the “evolution of the species” has all these past years been one (1) of my favorite subjects of discussion, ….. with the evolving of Homo sapiens sapiens as my most preferred topics that is 2nd only to ….. the evolution of the human brain/mind.

        And Gloateus M, just how was it possible for your noted processes like natural selection and/or reproductive isolation that resulted in “decent with modification” manage to create the physical attributes possessed by the Platypus?

        Gloateus M, here is an example of the ”circular reasoning” that you were nurtured to accept as scientific fact by your mentors, …… and which irritates the ell out of me when presented as a legitimate argument, to wit:

        In the case of the Cambrian, selection worked rapidly because of innovations such as vision, predation and the consequent development of calcareous shells and other hard body parts.

        Woweee, rapid selectivity was the driver of the aforesaid evolved innovations ,,,,,, and the evolved innovations was the driver of the aforesaid rapid selectivity. YUP, got your cake and ate it too, right?

        Me thinks you are confusing “random mutations” that rarely result in being highly beneficial to “survival of the species” …… with the “inherited instinct” that drives one’s desire for procreation of their species.

        Be an “original thinker”. ……. not just a quoter, mimicker, paraphraser, adlibber, etc., of another author’s commentary.

      • Samuel,

        If your idea of original thought is to posit HGT for which there is zero evidence, then on your planet “original” must mean “nonsensical”. You presumptuously claim without demonstrating any information or ability to understand evolution, but clearly you’re hopelessly out of date, assuming you ever were up to speed, which you’ve provided no reason to conclude.

        I don’t know what you find so inexplicable about the platypus. As I said, the ancestors of all mammals laid eggs. The evolution of marsupials and placentals is fairly well known. True placental mammals (the crown group including all modern placentals) arose from stem-group members of the clade Eutheria, which had existed since at least the Middle Jurassic period, about 170 Ma). These early eutherians were small, nocturnal insect eaters, with adaptations for life in trees.

        http://www.nature.com/nature/journal/v416/n6883/full/416816a.html

        True placentals may have originated in the Late Cretaceous around 90 Ma, but the earliest undisputed fossils are from the early Paleocene, 66 Ma, following the Cretaceous–Paleogene extinction event.

        http://science.sciencemag.org/content/339/6120/662

        I told you why monotremes survived on Australia while going extinct everywhere else from competition with aquatic placentals.

        http://www.pnas.org/content/106/40/17089.abstract

        There is nothing mysterious about platypus evolution, so no baseless conjecture as to HGT is required to explain it.

        Nor is there any need to invoke evidence-free HGT to explain evolution of large animals with hard body parts in the Cambrian and Precambrian. Please get current on animal evolution in the Cambrian.

        The burden of proof is on you to show which genes you imagine were transferred horizontally from what other organisms to account for which Cambrian evolutionary developments. Your conjecture is totally lacking in support from any discipline, whether genetics, comparative anatomy, embryology, paleontology or any other relevant source. You won’t even try, because you can’t. No such evidence exists.

        Many innovations formerly observed in the Cambrian are now known to have occurred in the Ediacaran. Looking more closely at the Burgess Shale and other fine-grained Cambrian sediments has also revealed the small, shell-less ancestors of trilobites, for instance.

        If instead of flights of fancy free of observed reality you instead had spent time studying the Precambrian discoveries of the past 60 years, especially the past 20, you wouldn’t have so embarrassed yourself.

        Since you have stooped to citing Wikipedia, here’s a good place for you to start educating yourself on paleontological, genetic, embryological and other biological advances since your undergrad days:

        http://www.pnas.org/content/106/40/17089.abstract

        Mutations can be beneficial, neutral or deleterious. People each have on average four somatic mutations and they accumulate in germ cells, which is why old fathers are important to evolution. When conditions change, previously lethal mutations can become beneficial, as was the case with nylon-eating bacteria. The single point mutation which turns sugar-eating bacteria into nylon-consuming microbes must have happened countless times before nylon entered the environment, but was always deadly. Now it has opened up a whole new bacterial food source.

        Selection and reproductive isolation are repeatedly observed facts.

      • A recent analysis of the Ediacaran Biota (575-541 Ma), and the relationship of some of its members to Phanerozoic Eon phyla. No surprise poriferans are found, since sponge fossils have been found from much earlier in the Precambrian, ie over 600 Ma:

        http://www.pnas.org/content/112/16/4865.full.pdf

        Significance

        Patterns of evolution, origination, and extinction of early animal life on this planet are largely interpreted from fossils of the soft-bodied Ediacara Biota, Earth’s earliest multicellular com-
        munities preserved globally. The record of these organisms predates the well-known Cambrian Explosion by nearly 40 million years and provides critical information concerning early
        experimentation with complex life-forms on Earth. Here we show that, although in appearance, these organisms look very strange and unfamiliar, many of them may have had a biology
        and/or ecology similar to animals today, and some were most certainly bilaterians, cnidarians, and poriferans.

      • You presumptuously claim without demonstrating any information or ability to understand evolution, but clearly you’re hopelessly out of date, assuming you ever were up to speed, which you’ve provided no reason to conclude.

        Gloateus, your above verbal tirade was 100% equivalent to that of an avidly believing proponent of CAGW or CAGWCC …… telling a real scientist that he/she is stupid, ignorant, uneducated and is ignoring the actual factual “scientific evidence” that is unquestionable literal proof that their claims of CO2 causing Anthropogenic Global Warming …… are “right as rain”.

        The evolution of marsupials and placentals is fairly well known.

        “YUP”, shur nuff is “fairly well known”, Gloateus, ……. and so is the abundant fossil evidence that definitely supports the claims of the “experts” concerning the evolution of the unique physical and mental attributes of Homo sapiens sapiens. Except for the FACT their claims “don’t pass the smell test”.

        Your conjecture is totally lacking in support from any discipline, whether genetics, comparative anatomy, embryology, paleontology or any other relevant source. You won’t even try, because you can’t. No such evidence exists.

        Good grief, ,,,,,,, Gloateus, …… I sure as hell wouldn’t be the first person in the last 150 years (Charles Darwin) that your “so called” experts in various disciplines ……. ignored, berated, admonished, badmouthed and/or publicly discredited, …… only to be later proven they were 100% correct.

        Gloateus, when your mimicked claims of accepted factual science of the natural world, ……. and/or the likewise claims of your beloved and adored mentors …… “don’t pass the smell test”, ….. meaning, …… said claims are not, and can’t be, …… supported via “common sense thinking, logical reasoning and/or intelligent deductions” ……. then physical or even mathematical evidence is an unnecessary requirement to discredit or disprove the aforesaid claims.

        I really don’t think that you comprehend the fact that “You are what your environment nurtured you to be”, ….. but your ignorance of that knowledge might somewhat be “corrected” iffen you take a few minutes to read and comprehend the contents/context of this published commentary by “clicking” the following hyperlink, …… A View of How the Human Mind Works

        Cheers

      • Samuel,

        It appears that you don’t get how science works.

        Other people with ideas present supporting evidence for them. You have zilch, zip, nada.

        For it to qualify as a scientific hypothesis, you would need to make testable, falsifiable predictions based upon your totally evidence-free conjecture.

        When you can do that, write your wild-@$$ed guess up as a scientific paper. Good luck with that.

        It’s not the workings of my human mind which need concern you but your complete lack of any scientific rigor at all.

      • YUP, shur nuff, Gloateus, ,,,,,,, and the early dinosaurs evolved feathers because they really hated falling out of trees and busting their arrses on the rocky ground ……. and your beloved mentors have tons of physical evidence that proves without a doubt that their evolutionary “feather” claims are 101% correct.

        I believe, ….. I believe, …… anything you want to tell me, ….. Gloateus Maximus, ….. anything you want to tell me.

        “I believe” because ……. I’m now far too damn old to be getting “F grades” from silly people who demand I believe everything they tell me.

        I’ve got my career ta think of, ya know.

      • Samuel,

        All the evidence in the world supports the observation that theropod dinosaurs evolved feathers, and no evidence contradicts this fact.

        Apparently you’ve never seen the fossils of feathered dinosaurs, nor observed their development in embryos nor the beta keratin of which they’re made in both modern birds and Mesozoic dinosaurs, nor the host of other features shared by birds and maniraptoran dinosaurs.

        Clearly, evidence is not your thing. Baseless, fact-free speculation is.

      • The Thermopolis, WY specimen of the dinobird Archaeopteryx, which I’ve been allowed to examine:

      • Gloateus, ,,,,,,, reading comprehension is not your forte, ……. is it?

        Me thinks you should quote my exact statement about “dinosaurs evolved feathers” before getting a case of “diarrhea of the mouth” and proving to the world what a devious character you are when confronted by someone who is far more intelligent than you are.

        And ps, your ability of mimicry of a subject matter does not constitute intelligence of said subject matter,

        Tape recorders, videos and Jukeboxes are super-duper “mimickers” of recorded subject matter but their intelligence and/or IQ rating is that of a box-of-rocks.

      • On what possible basis can you imagine yourself smarter than I?

        You’ve hatched an entirely evidence-free conjecture that HGT somehow accounts for the Cambrian explosion and platypus evolution. Not only have you no evidence for this wild speculation, but you can make no testable, falsifiable predictions based upon it, so it is the opposite of science.

        Making WGAs without any basis is not thinking outside the box. It’s not thinking, period.

        Clearly the mentally defective loon suffering delusions of competence in this discussion is you.

      • Thanks Pat. Modern plants both photosynthesise and respire. Was it the same back then? Or did it start as photosynthesis which produced oxygen and life then found a way to use the oxygen?

      • A very corrosive and toxic pollutant oxygen is… thankfully. O2 is the final electron receptor in the mitochodrial aerobic respiration electron transport chain.

        Now take a deep breath. Ahhh….Oxygen.

      • If I recall, the only source of oxygen that far back was the stromatolites, structures built up by layers of cyanobacteria.

      • Forest Gardener, good question. Modern photosynthesis has two parts, that evolved separately. The first to appear was Photosystem II, which uses sunlight to oxidize water into O2, and extract the electrons for use in their energetic metabolism.

        This ability evolved in cyanobacteria. It’s doubtful these bacteria used oxygen for their respiration (there wasn’t enough early-on). Most likely, they used sulfate or perhaps nitrate as their terminal electron acceptor. Both sulfate and nitrate reducing bacteria remain ubiquitous today.

    • What chemical reaction produced the oxygen?

      I suggest H2O provided the oxygen in the end. The hydrogen is partly stored in underground and underwater methane, and big part of the hydrogen just escaped the Earth.

      The amount of black carbon does not explain the large amount of free oxygen.

      Or did it start as photosynthesis which produced oxygen and life then found a way to use the oxygen?

      I think the starting part is complicated. Oxygen is a very poisonous gas, so the first phase is to protect from oxygen, which can be done by using it if it happens to available. Photosynthesis is possible only after there are some measures to handle the freed oxygen. However, freeing oxygen is a tool for bacteria, because if they can both tolerate some oxygen and create some oxygen, they can protect their environment from other competing bacteria which don’t handle free oxygen well. So using oxygen actively and protecting oneself from oxygen are not completely separate things. Efficient photosynthesis is done by chloroplasts which are kind of endosymbiotic bacteria inside an eukaryote. Efficient oxygen use is executed in mitochondria, which are another sort of ancient bacteria. Use of oxygen for good and bad is tightly bound to the evolution of complicated cells.

      • Resposting messed message, sorry mod.

        What chemical reaction produced the oxygen?

        I suggest H2O provided the oxygen in the end. The hydrogen is partly stored in underground and underwater methane, and big part of the hydrogen just escaped the Earth.

        The amount of black carbon does not explain the large amount of free oxygen.

        Or did it start as photosynthesis which produced oxygen and life then found a way to use the oxygen?

        I think the starting part is complicated. Oxygen is a very poisonous gas, so the first phase is to protect from oxygen, which can be done by using it if it happens to available. Photosynthesis is possible only after there are some measures to handle the freed oxygen. However, freeing oxygen is a tool for bacteria, because if they can both tolerate some oxygen and create some oxygen, they can protect their environment from other competing bacteria which don’t handle free oxygen well. So using oxygen actively and protecting oneself from oxygen are not completely separate things. Efficient photosynthesis is done by chloroplasts which are kind of endosymbiotic bacteria inside an eukaryote. Efficient oxygen use is executed in mitochondria, which are another sort of ancient bacteria. Use of oxygen for good and bad is tightly bound to the evolution of complicated cells.

      • The sun is thought to get weaker by about one percent per 110 million years back in time. Thus, at 2.4 Ga, it would have been some 22% dimmer than now.

    • See
      http://www.leif.org/EOS/2011RG000375.pdf

      Gough’s formula gives

      L(t)/L(0) = 1/( 1 + 0.4( 1- time/4.6 billion years))

      So 4.6 billion years ago the sun had a luminosity of about 0.714

      2.25 billion years ago, the sun was 2.35 billion years old and had a luminosity of about 0.836

      700 million years ago the sun was about 3.9 billion years old and had a luminosity of about 0.943

      0 billion years ago the sun is about 4.6 billion years old and has luminosity of 1.000

  6. Everything has an uncertainty in analytical science. The further back, the larger the uncertainty. Take this paper with a grain of paleoproterozoic salt.

    • The sad truth is, we really don’t know. The best course of action for mankind would be to increase our technology as quickly as possible so that we could survive it. And in that regard, abundant, cheap energy will be the key.

  7. I 2nd joelobryan’s thoughts.

    What are the chances that the paleomagnetic data that appears to place South Africa near the equator at the time of the dropstone deposition in Wyoming was actually due to the Earth’s magnetic field being in a state of transition/reversal?
    Also, Every reconstruction of prior supercontinents has North Africa butting up against North America, placing South Africa thousands of miles away from Wyoming.

    SR

    • Also, how does covering the Earth’s oceans with ice correlate with cyanobacteria proliferation?

      SR

      • Stevan
        That’s the interesting question the article fails to address – why did the Huronian glaciation and isolation of the atmosphere from the hydrosphere lead to enough photosynthesis to oxygenate the atmosphere? What was the chain of causation? And why is the report shy of giving this glaciation its proper name, the Huronian?

        Since it is in PNAS it should be without a paywall so maybe the actual paper addresses these points (and mentions “Huronian”)?

      • hypothesis: cyanobacteria produced oxygen anyway, rock weathering prevented oxygen build-up, glaciation prevented rocks oxidation, deglaciation made it happen again, hence oscillations

      • If the equatorial belt never froze or cyanobacteria produced oxygen anyway during Snowball Earth then Snowball Earth was just coincidental with the production of oxygen and the hypothesis implied in the title is, at best, misleading.

    • That configuration applied to Pangaea 200 Ma, but not to reconstructions of the Supercontinent Columbia, which formed around the time of the GOE or shortly thereafter (in geologic time).

      • Yep. That’s the earliest paleomap I found looking around the Internet. But the map is of an Earth about 470 million years younger than the time period the article refers to. Judging from our most recent 470 million years, a lot can happen in 470 million years. Our present continental configuration is surely vastly different than that of the mid to late Ordovician 470 million years back. My guess guess on this. The dates are probably valid. Baddeleyite is Zirconium Oxide and presumably is radiometrically dateable. The paleogeography is probably questionable. Small sample? No longitude information. Latitude estimates based on the assumption that everywhen and always the Earth’s magnetic field and rotational poles coincide?

  8. This never seemed to register with anyone else, but one of the most preposterous predictions of the climate models a while back, and the most important indication to me that the models were out to lunch, was a run by Andrew Lacis published at NASA (2012) where he took all the CO2 out of his model and it dropped GMAT 4.6C in the first year! In a decade he had a snowball earth and a 20C drop.

    Wow. Still doesn’t work for me.

  9. Perhaps snowball Earth is an endothermic reaction from water electrolysis…. and Oxygen production back then was electrochemical rather than biological?

    I can’t see there being much in the form of green plants or algae when most of the planet is frozen solid?

    • There were no green plants until much later. The photosynthetic organisms at that time were cyanobacteria, the so-called blue-green algae, which aren’t algae.

      Snow, ice and cold don’t deter cyanobacteria, as long as photons can still reach them.

  10. Using a mass spectrometer, the age of the rocks is determined by measuring the buildup of lead from the radioactive decay of uranium

    Serious question. I do want to know.

    How does the method distinguish Lead from decay of Uranium and basline Lead that’s in the ground anyway?

      • So zircon (or in this case baddeleyite) selects against absorption of lead and thus any lead found in it must be a result of radioactive decay.

        Sounds good as baddeleyite crystals should have time to equilibrate over millions of years.

        But it also sounds bad as any disturbance to the crystal matrix will bring about to contamination. And over millions of years you would expect there to be some damage. If only from the radioactive decay without needing any mechanical or thermal damage.

        Not saying that I disbelieve this process has any value. But the number of independent samples required to gainany confidence that gross contamination has been avoided… Well, this isn’t as good as Carbon 14 dating

  11. The snowball Earth hypothesis has a serious problem in that nobody can figure out how the planet can recover from that situation. It is sort of a dead end for a planet, that continues losing atmosphere and water over billions of years until it reaches a Mars state.

    It is impossible to demonstrate that the entire planet was frozen, only that certain places were frozen, but we do not know where the poles were exactly at those times.

    Alternatively the tropical band was never frozen and the atmosphere and oceans were never isolated.

    I don’t think we can know, and it is surprising that some researchers display such security that their theory reflects what actually happen, given that theories cannot be proven right, just explain evidence and not being falsified.

    • @Javier February 7, 2017 at 1:24 am
      “The snowball Earth hypothesis has a serious problem in that nobody can figure out how the planet can recover from that situation.”
      The answer seems straightforward once you realize that the geothermal flux (GF) of 100 mW/m^2 is sufficient to bring the current average ocean column (~3700m) from freezing to boiling in about half a million years.
      An ice cover and/or a solar heated warmer surface layer is sufficient to prevent the deep oceans from releasing the GF energy to the atmosphere so they warm up.
      To me this explains the very high temperatures on Earth, and could also explain the high temperatures on Mars, as long as it was mostly covered with water.

      • Yes, I agree too, Ptolemy2. Some of the explanations for coming out of a snowball Earth like geothermal energy, or volcanism, if powerful enough should have prevented a completely frozen planet for existing for tens to hundreds of millions of years. Ice-free tropical oceans were probably a feature of those deep ice ages of the past.

    • IMO getting out of a Snowball Earth scenario is easy. Just wait for the continents to move.

      Also, not all Snowball events are created equal. Three states are possible, ie 1) Iceball Earth, similar to a giant Jovian or Saturnian moon covered in solid water ice, 2) a true Snowball Earth, with land and sea ice down to low latitudes, but not necessarily permanent continuous drift ice, and 3) Slushball Earth, with at least seasonally ice-free conditions in tropical seas and even at low elevations on land at low latitudes.

    • Javier February 7, 2017 at 1:24 am

      The snowball Earth hypothesis has a serious problem in that nobody can figure out how the planet can recover from that situation.

      Javier, …… you should have asked me, ….. because I would have told you “how it was possible” for the earth to “recover” from a “snowball” situation.

      And the simple answer is …… “volcanism”.

      The rocks, dirt and dust particulate being emitted by erupting volcanoes would “settle” on the snow/ice surfaces which would then exacerbate the melting via solar irradiance.

      The same as the current claims of Arctic ice melting due to ….. airborne dust particulate from China and/or airborne “black carbon” from Russia.

      • Even simpler explanation, the cold sun, warmed. Why is the better question. A young sun, with all the necessary ingredients, would have been hotter, not colder. Further expanded, towards us, earth, in our orbit. Why did the sun change? It stopped feeding as its orbit path took it to less dusty areas? And space became cleaner? Or, as our star aged, chemical composition changed to something less heat producing? All fuels reduce, some faster then others.
        Another odd thing, the billions of years where there was apparently no plate tectonics? Then, what started it? Must have been a big old bump. That would have changed our orbital parameters, but, then no one was here to record it.

      • Jim,

        Plate tectonics started early in Earth’s history, probably since after the moon-making impact.

  12. Not sure what to think of this and not helped by the name of the area, ‘ongeluk’. It’s Dutch for ‘accident’ or ‘bad luck’.

  13. Another issue is the natural heat of the Earth: it is presumed that non-withstanding the weak Sun idea that the Earth’s internal heat was greater further back in time and that there was much more volcanic activity. This is also how it is claimed the Earth gradually escaped the Snowball effect, by spewing out gases and volcanic dust that eventually greyed or blackened up the ice and warmed the planet slowly out of the ice.
    But it does raise the issue of why the greater internal heat didn’t halt the snowball process in the first place.

    • Also 2.5 G Y ago the Earth was less than half of its present age, its crust must have been much thinner and as a consequence the geothermal radiation would have been by far greater than it is currently.

    • The natural heat of the Earth has an amusing tale.

      Lord Kelvin reckoned that Earth must have begun completely molten, and calculated that therefore Earth could be no older than 40 million years. This of course upset the geologists who saw, via sedimentation alone, that it had to be much older; Kelvin recalculated 20 million years and said he could take it even lower.

      Later, in 1904 Rutherford gave a talk about the new phenomenon of radioactivity. He was going to address how this energy affected our understanding of the age of the Earth. To his dismay, Lord Kelvin chose to attend. To his relief, the elderly scientist dozed off. To his dismay, Kelvin woke back up just as Rutherford reached the critical point of his talk.

      In his own words,
      “To my relief, Kelvin fell fast asleep, but as I came to the important point, I saw the old bird sit up, open an eye and cock a baleful glance at me.

      “Then a sudden inspiration came, and I said Lord Kelvin had limited the age of the Earth, provided no new source [of heat] was discovered. That prophetic utterance referred to what we are now considering tonight, radium! Behold! The old boy beamed upon me.”

  14. Evidence of glacial activity in the tropics does not necessarily mean the ocean was frozen as well.
    Re. link from ptolemy2….to note the “importance of tectonic preconditions under which glaciologist-epochs develop”. Snow tends to settle on mountain tops even in the tropics.

    • They seem to infer glaciation and glacial ice moving out over the seas from the presence of dropstones. My understanding is that dropstones are chunks of rock grabbed up by glaciers and dropped into otherwise undisturbed marine or lacustrian sediments when the ice eventually melts.

      • Yes, and often not until glaciers have become icebergs and floated hundreds or even thousands of miles from say….Antarctica?

  15. Hmm. I thought that ocean photosynthesis had been producing O2 for a long time, hundreds of millions of yrs or more, oxidizing dissolved iron in the ocean (the huge iron oxide deposits everywhere), before the iron was finally used up and starting accumulating in the atmosphere.

    • That’s my understanding . That the O2 came from a > 20% CO2 , 0% O2 atmosphere by biological sequestration as coal , gas , and limestone .
      How a “snowball” period would do anything other than retard that conversion I fail to understand .

  16. Ever since my first years studying geology I have been fascinated with globally extensive glaciation. So, it’s no surprise the first book I wrote taps on this idea. (published this week! Shameless plug for Icefall! Yay!) The causes I used in my story for global glaciation ending modern humanity along with most of the life on Earth are about as scientific as explaining how fast zombies came to be, but that doesn’t make me any less fascinated for the scientific study of actual *global* glaciation.
    Great reading the comments in the thread, as well as ptolemy2’s pdf link.

  17. There is some observational data that indicates the subject did happen. Arguing climatic reasons why it could or could not have happened makes no sense given the different conditions 2.5 billion years ago ie, earth orbit, obliquity, precession, solar tsi production, atmospheric density and composition, ocean depths and composition, lunar orbit and influences, etc., just to name a few. An interesting subject, none the less, when one then begins to consider future ramifications beyond that 2.5 bya.

    • It could very well have contributed. Oxygen in the atmosphere means also ozone, that alters the temperature gradient of the atmosphere, warming the stratosphere and cooling the troposphere.

  18. I had the pleasure of working for Dr. Chamberlain. I spent many hours at the microscope picking zircons much smaller than the tip of a human hair. The zircons were chosen for size, double termination,a lack of cracks and other defects. After enough zircons were pulled from a sample they were abraded down to a core to remove any part that might have been contaminated by other uranium/lead sources. The zircons were then dissolved in nitric acid and run through a mass spectrometer to obtain ratios of daughter products which were compared to half life ratios to determine the age of the samples. It took several 5 gallon buckets of rock to produce a couple of tiny samples, if we were lucky. Dr. Chamberlain and the students that work for him do some meticulous work.

    • Not that I expect, or even want, an answer – but just how does one go about picking a microscopic zircon crystal from a rock?

      • Sorry about taking so long to reply. Rock is crushed in a ball mill using steel balls or chains to break down the rock to fine particles. Some small Zircon crystals with a hardness of about 7.5 manage to stay intact through the process of milling and separation. Under a microscope they looked like a king’s ransom in jewels.

      • Yes, John, sorry but observations of nature are how science is done. Your cult however is based upon made-up stories. That’s myth, not science.

        Where the man-made-up supposed Word of God differs from the actual Work of God, you have to go with the observations. That is, unless your god is unspeakably evil, sadistic, incompetent and deceptive.

      • My favorite part;

        “With all the discussion of climate change in the present day, understanding how Earth responded and the effects on the atmosphere in the past may help us predict the future.”

      • Yes. It describes the unavoidable conclusion of attempting to believe literally in biblical passages when comparing them with objective reality.

      • JohnKnight
        February 8, 2017 at 1:05 pm

        That obeisance to the prevailing paradigm is not the heart of the paper.

        Diamictite drop stones at low latitudes are observations scientific evidence. Your biblical myths are fantasies. Not being able to grasp the difference and confusing fact with fantasy could be considered a mental health issue, were it not a religious cult.

  19. The snow-line in the tropics is about 5km high. So even today if an equatorial continent was big enough and high enough an ice sheet could easily form at the equator but would still leave the surrounding warm sea free to provide the moisture for snow.

  20. Question to the geologists on this thread:
    Is any evidence available for a massive magmatic event in the oceans around the peak temperatures in this graph?

    The latest warm period can be linked to the Ontong Java event.
    Given the maximum age of the current oceanic crust I’m afraid older events can not be traced anymore, but who knows.

  21. What I’m interested in, and doesn’t seem to be addressed, is by what mechanism or theorized mechanism was oxygen generation caused by snowball Earth events? They certainly seem to be implying it was a causative factor.

    • During a low-latitude ice-age large amounts of hydrogen peroxide produced by UV light gets incorporated into the ice. When the temperature rises and the ice melts the hydrogen peroxide breaks down into water and oxygen. There is actually some H2O2 in Antarctic snow today, but not enough to matter because there is not enough UV light at high latitudes.

      • On actually reading the paper I see that he ascribes the oxygenation to increased photosynthetic activity causing drawdown of methane and carbon dioxide and hence glaciation. However this is probably just a genuflection to the almighty power of greenhouse gases, since elsewhere in the paper it is clearly shown that “the great oxygenation evant” actually happened just after the glaciation, so I tend to believe in the proxide mechanism instead, particularly since the (relatively) high-oxygen stage seems to have been short. Cyanobacteria would presumably have gone on producing oxygen.

  22. “These rocks, known as diamictites, have large drop stones that depress very fine-grained mudstone. The large stones dropped from the underside of glacial sheets as they spread out and melted over shallow seas, similar to sediments beneath the Ross sea ice sheet of Antarctica today.”

    I wonder how he determined that they were from the underside of a shelf-ice rather than from melting icebergs (which is usually the case)

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