Growth rings on rocks give up North American climate secrets

3 millimeters of soil deposits detail 120,000 years of climate history

From the  UNIVERSITY OF CALIFORNIA – BERKELEY

This is a map of the predominant weather patterns in mid-latitude North American from 70,000 to 55,000 years ago. The large ice sheet covering the northeastern portion of the continent caused a strong high pressure system to persist above it, which drew Gulf of Mexico-sourced precipitation (red arrows) into the mid-continent and Wyoming (white star). The result was rainy summers during this time, and possibly drier winters. CREDIT Erik Oerter

This is a map of the predominant weather patterns in mid-latitude North American from 70,000 to 55,000 years ago. The large ice sheet covering the northeastern portion of the continent caused a strong high pressure system to persist above it, which drew Gulf of Mexico-sourced precipitation (red arrows) into the mid-continent and Wyoming (white star). The result was rainy summers during this time, and possibly drier winters.
CREDIT Erik Oerter

Scientists have found a new way to tease out signals about Earth’s climatic past from soil deposits on gravel and pebbles, adding an unprecedented level of detail to the existing paleoclimate record and revealing a time in North America’s past when summers were wetter than normal.

A research team led by soil scientists at the University of California, Berkeley obtained data about precipitation and temperature in North America spanning the past 120,000 years, which covers glacial and interglacial periods during the Pleistocene Epoch. They did this at thousand-year resolutions — a blink of an eye in geologic terms — through a microanalysis of the carbonate deposits that formed growth rings around rocks, some measuring just 3 millimeters thick.

“The cool thing that this study reveals is that within soil — an unlikely reservoir given how ‘messy’ most people think it is — there is a mineral that accumulates steadily and creates some of the most detailed information to date on the Earth’s past climates,” said senior author Ronald Amundson, a UC Berkeley professor of environmental science, policy and management.

The study, to be published Monday, Jan. 11, in the Proceedings of the National Academy of Sciences, shows the rich potential held within soil deposits known as pedothems, which form growth rings on rocks. The samples used in the study came from Wyoming’s Wind River Basin.

Because these soil deposits are commonly found in drylands all over the world, they can provide a rich source of data for paleoclimatologists, the authors said.

“We can now begin to develop records of how local and regional climate boundaries have shifted through time and in response to worldwide warming or cooling,” said study lead author Erik Oerter, who conducted the research as part of his UC Berkeley Ph.D. dissertation.

120,000 years of history in 3 millimeters of rock

Pedothems are a powerful complement to existing geological records of past climate, including ice cores, lake and ocean sediments, and stalactites and stalagmites in caves. They have the advantage of being fairly ubiquitous in regions now populated by humans, unlike the polar regions where ice cores are often obtained.

Key advances in the ability to precisely analyze micro-samples of soil deposits enabled researchers to extract telltale signs of climate change.

“By using micro-analytical measurements on spots as small as 0.01 mm in diameter, we can develop time series of past climate conditions in a way that no one has done before,” said Oerter. “It is evident that the carbonate coatings formed in concentric bands around the rocks, much like the annual growth rings in a tree, except that these laminations form over timescales of several hundred years.”

The researchers used laser ablation and an ion microprobe, much like a tiny dental drill, to obtain microscopic samples for analysis. Uranium isotopes were used to date the deposits, while oxygen and carbon isotopes revealed clues about the precipitation, temperature and soil respiration at the time the mineral was formed.

For instance, warmer rain from the Gulf of Mexico will result in higher levels of oxygen 18 compared with the cold precipitation from snowstorms blowing eastward across the Rockies. The ratio of carbon 13 and carbon 12 isotopes reflect levels of soil respiration, which is a proxy for plant productivity.

Uranium isotopes were used for dating the sample, but they can also be used to calculate how much rain the soil receives, serving as a type of “paleo rain gauge,” said Oerter, who is now a postdoctoral researcher at the University of Utah.

Finding what other records couldn’t

The new data revealed that 70,000 to 55,000 years ago, in the midst of a minor ice age, the pattern of precipitation in North America shifted from one dominated by a west-to-east flow of storms from the north Pacific to a south-to-north flow from the Gulf of Mexico. The researchers attributed that to a stable, high-pressure system that parked itself over massive ice sheets that covered eastern Canada and northeastern United States, which helped bring up more air from the south.

That atmospheric circulation translated into wetter summers and drier winters in central North America, a reverse of the usual pattern in which more precipitation falls in the winter.

“This is a new insight from geologic sources of paleoclimate data,” said Oerter. “The techniques that we developed can now be applied to similar soil deposits to fill in key gaps in the paleoclimate record. The information will be useful to improve the accuracy of climate models by providing known conditions to calibrate them to.”

###

Advertisements

91 thoughts on “Growth rings on rocks give up North American climate secrets

  1. Now we wait while the record is “adjusted” to show unprecedented climate change.
    Maybe we should start a pool to see how long until we here the dreaded “It’s worse than we thought.”

  2. I’m afraid that you’re right. Any new technique discovered today is going to be hopelessly corrupted …

    • Dang, I was just going out to get my garbage can, and I stubbed my toe in the back yard garden, and screwed up the last 15.736 million years of climate. history.
      g

      • Ok…already laughing and I’m only three comments in! Thanks George! Rolling stones gather no moss, but apparently sitting rocks gather information! And just because it’s Berkley guys, doesnt mean it HAS to be crap or that it will be used poorly. I think it will be cool if it turns out to be a viable, valid source of information.
        It’s SCIENCE. They can pervert how it’s presented for sure! But this data is everywhere and easy to get to, so it’s easier to fight back if they try!

      • Aphan,
        “It’s SCIENCE”
        So is CAWG . . Where’s your skepticism?
        “But this data is everywhere and easy to get to, so it’s easier to fight back if they try!”
        How? Air is everywhere, and that’s not providing any sort of fail-safe against “SCIENCE” becoming a freaking monster, it seems to me.
        Below you wrote;
        “We cannot infer motives to anyone without letting go of reason.”
        If you feel this is true, then don’t infer good or selfless motives to these folks, I say . . be consistent, not trusting by default.

        • JohnKnight-
          Me-“It’s SCIENCE”
          JK- So is CAWG . . Where’s your skepticism?
          No, it’s NOT science. Nothing about AGW or CAGW follows the Scientific Method because the Scientific Method requires EVIDENCE and repeated, replicated experimentation.
          Me-“But this data is everywhere and easy to get to, so it’s easier to fight back if they try!”
          JK-How? Air is everywhere, and that’s not providing any sort of fail-safe against “SCIENCE” becoming a freaking monster, it seems to me.
          Because its not one of a handful of “ice cores” or “sediment cores” that one has to get on a LIST to even view, much less study.
          JK-Below you wrote;
          Me-“We cannot infer motives to anyone without letting go of reason.”
          JK-If you feel this is true, then don’t infer good or selfless motives to these folks, I say . . be consistent, not trusting by default.
          That’s a false dichotomy JK. There are more than two options here. One of them is NEUTRAL. I did NOT infer good or selfless motives. I stated that WE don’t have any evidence to infer BAD or selfish motives to these folks. I AM being consistent. That you THINK otherwise is your problem, not mine.

      • george, I wonder how they know their rocks and pebbles stayed in the same place and orientation for 120,000 years. If they were buried, exposed and then reburied many times, I wonder if that would change their assumptions? Would it change the layering? And, the Wind River Ranges have glaciers now, what was it like through 120 millennia?

  3. The fact that they say nothing (here) about the last 12k years makes me wonder whether their data say unfashionable things about CAGW.

      • The research is in its infancy. It will need funding to expand the time frame and begin study outside of Wyoming. It would be surprising if the PR and paper weren’t written with hopes for more funding.

      • There is undoubtedly a full professorship or two and at least 5 PhD research grants here somewhere. And, as always, “just a little more money and we can really get some GOOD data” will be the mantra!

      • I am with you NW sage. Ion probes? This is as useful to society as counting the number of angels who can dance on a pin head. The physical samples they are testing are so tiny that I doubt this will be proven over time to be a valid method of determining anything about past climates. The error bars must be huge. But of course, the researchers involved will claim that, with lots more money, they can tell us which way the wind was blowing on a particular Saturday in June 55,739BC!!
        The only thing I can say in their favour is that they actually did their own research instead of re-anylysing old data.

      • “”””……
        NW sage
        January 12, 2016 at 5:12 pm
        There is undoubtedly a full professorship or two and at least 5 PhD research grants here somewhere. …..”””””
        There is also a 65% chance that those PhD graduates will THE world’s leading authority on that subject.
        Which is a polite way of saying they are the ONLY persons on earth with ANY interest in that subject.
        No future job in that.
        G

    • dearieme on January 12, 2016 at 4:49 am
      The fact that they say nothing (here) about the last 12k years makes me wonder whether their data say unfashionable things about CAGW.
      It makes you wonder if there is a business model in CAGW blackmail: “we’ve got this data that trashes CAGW, what’s it worth to keep it quiet?”

  4. The climate now tends to be that an upper level low pressure sits over northern Canada and over in the northern Soviet Union where you get a peanut shaped double vortex. These are blocked by the warmer ocean air and sit and spin over January and February till the days light gets longer and warms the land more closer to the ocean temperature where the polar vortex can finally break up. With the El Nino, we might get some push of warmer air up into the bottom of the Canadian low and won’t have such a cold winter in the northern US. We’ll have really cold spats but with warm spats in between, unlike the last two years.

    • Mark, wouldn’t the width of the carbonate layers be influenced by atmospheric CO2, precipitation, etc.?

  5. So…they figured out that gigantic ice sheets covering the entire Hudson Bay/east coast regions of the planet causes…climate change! And yes, warmth flows out of the Gulf of Mexico and has virtually no effect on the giant ice sheet that is caused by cold settling over Hudson Bay.
    I have said for years that the fact that the Hudson Bay region is the epic-center of Ice Age processes that we should look mainly and even only at that region to detect whether or not we are going into a warmer or colder climate.
    http://www.ec.gc.ca/glaces-ice/ has daily ice sheet information.
    It is interesting to me that the air flow during Ice Ages is mainly from the Gulf of Mexico in winter rather than from the north, dipping across Alaska and down into the Middle West and then looping up along the East Coast again.
    This reversal definitely changed the climate in the Midwest and West during the Ice Ages when mastodons roamed Los Angeles and Arizona.

    • No one doubted that the ice sheets changed the climate.
      This study gives a glimpse into how the climate was changed.
      “epic-center”? Let’s keep that quiet, they already have an ego problem up there.

    • Only 70-55 thousand years ago, and only during the summers. Obviously high pressure didn’t sit over those ice sheets most of the time during glacials.

    • EMS – Air flow from GofM in Winter rather than from North?
      The researchers attributed that to a stable, high-pressure system that parked itself over massive ice sheets that covered eastern Canada and northeastern United States, which helped bring up more air from the south.
      That atmospheric circulation translated into wetter summers and drier winters in central North America, a reverse of the usual pattern in which more precipitation falls in the winter. ,

      I read that as just the opposite of what you said. Note, the Berkley folks are wrong in that the Northern plains currently get more rain in the summer, not winter.
      http://www.usclimatedata.com/climate/sheridan/wyoming/united-states/uswy0154

  6. My God. To hear these ravings. It’s like listening to lunatics in a asylum.
    We do not have the ability to predict or control the climate, no matter what they say. We do not understand it. It may so chaotic that it will never be predictable in any useful sense of that word, or in time frames that are meaningful to humans. Example: What good is an accurate (90%) prediction that the Earth will experience an “ice age” beginning in 5,230 years?
    But, these climatologists are great at explaining what happened though, Just ask them.
    We can only adapt to the climate, as we have been doing for many thousands of years, and, may I say, quite successfully in the last few centuries. The anti-scientific and pseudo-scientific atmosphere of our culture is the biggest problem we face with “climate change.”

    • Not all of them are “raving”. (A lot of the “raving” comes from those who use CAGW as a lever to reach some other goal.)
      Other than that, spot on!

  7. This is the first study of its kind, and we’re supposed to believe that they got it all right. Over the past 3 years the new story line is “now we know” just because someone did a single study, of limited scope, and uncorroborated by other methods. A lot of it seems to come from UC Berkley. I’m thinking RICO

    • Using your logic, there would never be any studies on issues that have never been studied before.
      After all, the first study on any topic is by definition a waste of time.

      • I get that from some comments here already too Mark! Good grief people, we LIKE science. Science is GOOD, this is how science works! We figure out a new source of info, we study it, we make determinations about it, we write papers about what we found and what we THINK it might mean in the context of other sources!
        No one (except idiots) believes that studies establish “the truth” on anything! All studies do is share information and the methods used to collect and process it! Scientists are ALLOWED to reach conclusions! Then other scientists are ALLOWED to run experiments and challenge the prior conclusions if they get different results! The article does not say anything about proving AGW. The scientist said we can use this to make the models more accurate. That is a GOOD thing.

      • I don’t know if Mark from the Midwest was suggesting anything more than not to take the study as conclusively settling the issue. For my part what jumped out was the reliance on nuclear isotopes and assuming a whole list of processes for them to end up in varying degrees of concentration in these sediments, I don’t know for sure that there isn’t a long road to establish that assumption as a certainty.

      • There are faulty “One Study Wonders” that are latched onto because they seem to produce the result desired by someone else.
        But there are also first studies that are ground breaking and enlightening.
        It’s tough sometimes to tell which is which based how it is used.

    • I do agree with this sentiment. After all, it’s another proxy method for inferring what happened in the past. To proclaim that “we know” anything based on this study of carbonate deposits comes off as arrogant. Some skepticism is in order.

    • UC B is truly the cornucopia of fruits and nuts in the eyes of UIUC, Penn State and Mizzou Phd’s I know.

    • Fossilage’s point is exactly right, I’m getting tired of language that suggests that someone has found “the answer.” For the most part a study like this may just begin to suggest what the answer “might,” again “might” be.
      This might very well be a promising and useful direction, but given the way they’ve strung their dependencies together it would take many replications, in many environments to be sure.

  8. Very cool! This technique could provide all kinds of information that we can only speculate about now. I’d be most curious to learn what was going on after the last glacial maximum when earth started to warm back up, and farther back to know if its a climate pattern that initiates these ice age epochs in the first place, or does it have to do with earth’s tilt, position relative to the sun, or some very-long term solar cycle we’re not aware of yet. etc. etc. etc.
    I have no idea how much this technique can contribute to our understanding of all this stuff, but being able to glean information from sources like this will help us make much more educated guesses about the past. Very interesting stuff.

    • I agree. It is important that new techniques are tried, and I found this interesting. It is, however, not yet duplicated and, therefore, unproven. I’m beginning to feel sorry for the young PhD students who have to blow their own horn loudly in order to get a shot at a permanent university job. The labelling of this method as the best ever devised is truly sad. It’s just another potential proxy, and if results allow only millennial guesstimates it will be of limited value. Not everything is ground-breaking (pun intended). Kudos for the effort.

      • We cannot infer motives to anyone without letting go of reason. Science is exciting when done right, and new discoveries should be so exciting you want to tell everyone! Let them holler!
        And please don’t put words in their mouths, because that is a tactic of alarmists. They did not proclaim that this method was the best ever! Acting like this is like handing the alarmists bullets to load their guns with. It can lend creedence to their cries of “anti science” and “science deniers”. It’s possible to be TOO skeptical.

      • I thought the purpose of getting an education was to be able to do stuff that was useful and could make life better for everyone.
        So I do not regard getting a shot at a permanent university job as a legitimate reason for getting a PhD. That just produces even more people who don’t know how to do anything useful.
        65% of ALL USA university Physics PhD graduates never ever get a full time permanent job using their specialty to do something useful. 5% get a temporary job in their field, and then have to get retrained to do something useful.
        Only 30% get their PhD in something someone is willing to pay them money to do something useful.
        They used to teach Latin in schools, mostly to provide a future supply of Latin teachers in schools.
        Now it seems to be computer science, in order to get more people to program traffic lights to stop as much traffic as they can. The sort of people that gave us Micro$oft Windows.
        g

  9. “70,000 to 55,000 years ago, in the midst of a minor ice age,”
    I have never heard it called a minor ice age before and couldn’t find any reference through google. Is anyone familiar with the term?

    • People use the term “ice age” very freely. We live within an ice age which has lasted for about 2.8 million years. Within this ice age are long periods of glaciation. That time frame of 70,000 to 55,000 years ago was right in the midst of the last major glaciation period. I would imagine that the reference to a “a minor ice age” here is to a period wherein there was a little extra “cooling” (stadial) within the glaciation period. If the reference had been to a “stadial” of 70,000 to 55,000 years ago, it would have been technically correct.

      • Promoting the understanding of the relationship between “Ice Age”, “glacial period” and “interglacial period” is key to dispelling the confusion (deliberate or otherwise) surrounding the anthropogenic climate change brouhaha.

    • As FJShepard notes, 70K-55K years ago is within the Wisconsinan glaciation period.

      …cooling and drying of the climate led to a cold, arid maximum about 70,000 years ago…
      a fairly cold phase, in the ‘middling’ period between the two main glacial maxima. …Delcourt & Delcourt suggest that ice extent over eastern Canada was only slightly less that its maximum extent around 20,000 y.a., and that it extended just south of the Great Lakes.

      http://www.esd.ornl.gov/projects/qen/nercNORTHAMERICA.html

      Sometime after about 100,000 years, ice caps formed and expanded in several parts of Canada. Major areas of accumulation included the Keewatin Sector, the Labradorian Sector and the Foxe-Baffin Sector. Minor ice caps formed in the Atlantic Provinces and the arctic islands. In time, these ice caps coalesced, forming the Laurentide ice sheet. At about the same time, valley glaciers expanded in the western mountains and eventually formed the Cordilleran ice sheet.

      http://www.thecanadianencyclopedia.ca/en/article/glaciation/

  10. “They did this at thousand-year resolutions — a blink of an eye in geologic terms —”
    Well at least they are not trying to say a 30 year period is “proof” that something is changing.

    • Tom in Florida,
      This was exactly the phrase that I found encouraging. AGW alarmists are so often blind to the concept of geologic time. Erik Oerter has escaped Berkley and is now doing research at Utah. His tweets give no indication of activism. One of his recent tweets simply stated “Geology will fundamentally transform the way you see the world.” He seems follow the science and not an agenda.
      I for one will follow his work with great interest.

    • Tom In Florida?
      “Well at least they are not trying to say a 30 year period is “proof” that something is changing.”
      I am not sure what you mean, because the “pause”the last 20 years seems to have been “proof” against AGW that the skeptics are using. So to me skeptics should be careful, but then again the warmists are only using a 150 years time frame.

  11. A minor nit to harvest:
    The article says “70, 000 to 55, 000 years ago, in the midst of a minor ice age”; that is sloppy ( if common) usage.
    Right Now we are in an ice age. The cycle of 100,000 years of ice is a “glacial” in our present ice age. The holocene is a short warm period in our present ice age .
    The author is really taliking about stadials ( cold ) and interstadials ( warm ) in the last glacial period in our present ice age.
    Never forget that this IS an ice age and the warm interglacial is only a transitory blip, with periodic stadial and interstadial excursions possible at any time. Climate is not static and has not been…
    https://en.m.wikipedia.org/wiki/Stadial

    Generally, stadials endure for a thousand years or less, interstadials for less than ten thousand years, interglacials for more than ten thousand and glacials for about one hundred thousand. The Bølling Oscillation and the Allerød Oscillation, where they are not clearly distinguished in the stratigraphy, are taken together to form the Bølling/Allerød interstadial, and dated from about 14,700 to 12,700 years before the present.
    Greenland ice cores show 24 interstadials during the one hundred thousand years of the Wisconsin glaciation. Referred to as the Dansgaard-Oeschger events, they have been extensively studied, and in their northern European contexts are sometimes named after towns, such as the Brorup, the Odderade, the Oerel, the Glinde, the Hengelo, the Denekamp, etc.

    The natural cycles of a few million years have not ended. Using the correct words reminds of that fact.

  12. Use of an old term in the first abstract paragraph: “unprecedented”…. Then, almost fatuously, the introduction of “pedothem”. Carbonate, no less. Some kind of strange reaction involving humic acid, no doubt. And the thousand year resolution….they were almost crowing about that, having been trying for the last thirty to ram home the significance of 150 years of climate, not even a nerve-impulse of the eyelid.
    Nice Try, Berkeley.

  13. Interesting of course. And probably worthwhile. But I think we need a lot more data from a lot more places. And I for one would like a plausible explanation for a low elevation ice shield persisting under a permanent high pressure area at latitudes where Summer sun elevation angles would be 70 degrees or more. I should think that mid-latitude, low elevation iceshields require persistent cloud cover and/or abundant cold weather precipitation. Neither of those seem consistent with high pressure.

  14. “The information will be useful to improve the accuracy of climate models by providing known conditions to calibrate them to.”
    I thought these were serious scientists doing good work til they pasted this non sequitur on the end. It creates doubt as to the validity of their work.

    • How is that a BAD thing? Don’t the models NEED to improve? Isn’t their inaccuracy the biggest problem? Isn’t he admitting that they are currently calibrated with UNknown conditions? Serious scientists need and use models all the time.

      • The models are beyond calibration. Nothing in their study will fix the models. A few data points from antiquity are meaningless.

    • Hey, if we had the numbers of the lottery from 10,000 years ago our Lottery Number Generator™ could also be better calibrated. /s

  15. When I studied Pleistocene geology in the 50s, Ice age used to be restricted to the period of the ice. Since I graduated, the whole science of geology has been screwed up in this fashion. I was unhappy when they took the very highly respected ‘Geology’ and changed it to the come-down ‘Earth Science’. This was because of the new space exploration and they wanted to sound more sciency. Unfortunately, it really took a leaf out of the social sciences book, who use ‘science’ as part of the name in a protesteth-too-much fashion, just to be sure everyone thinks their long corrupted, politicized discipline IS a science. We do this a lot. Think why the Congo calls itself the ‘Democratic’ Republic of the Congo’. We wouldn’t want the place thought to be a hell hole run by a despot, or something. Or what about Deutsche Demokratische Republik (DDR): now there is a democracy that is warmly remembered.
    The new geology decided to obscure itself by changing rock names from perfectly functional mineralogically-based names to type locality/generic (?) names. I was away in Africa in mid 60s mapping real geology when this began to happen. When I returned, I joined the Geological Association of Canada but soon didn’t renew because the journals were full of newspeak and I’m not a guy who easily gets with the program. Nevertheless, I’ve functioned as a consultant very adequately for more than 35years.
    “By using micro-analytical measurements on spots as small as 0.01 mm in diameter, we can develop time series of past..”
    This is a misunderstanding by the writer of the PR. Laser ablation and microprobe work disturb only this small area (0.01mm) of an otherwise continuous ‘skin’ of these carbonates. There would be no interest in just an area of the material this size. I hope they did many 0.01mm spots on the same specimen to ensure they don’t have some kind of outlier. The technique itself is well developed in identifying and analyzing even trace minerals in a sample. Laser ablation actually makes a ‘puff’ of plasma that is chemically analyzed.

  16. That seems to be a fairly detailed map of a good portion of North America, based solely on some soil samples taken from one spot in Wyoming. Not sure anyone could take 10,000 years of detailed weather measurements at Casper and tell you what was happening in New Hampshire all that time. These soil rings must be really special!

  17. So this work may indicate the (not surprising) persistence if a high pressure zone over a region of the ice. The question remains, though: Moisture from which body of water primarily fed the growth of the ice sheets? An open Arctic Ocean, or perhaps a persistent Low over Baffin Island drawing moisture from a southeasterly direction? Or ‘other’/’all of the above’?

  18. “The new data revealed that 70,000 to 55,000 years ago, in the midst of a minor ice age, ”
    A minor glaciation is more accurate.
    An ice age is a series of glacials and interglacials about 10-12 million years long. We are two million years into the ice age and 12,500 years into this interglacial period. The Little Ice Age is a misnomer; it should be The Little Glacial Period.

  19. While this appears to be a great innovation and some diligent detailed work too, it greatly saddens me that the public reputation of climate science has been so tarnished by the actions of people like those at Penn State and the University of East Anglia that I am more than tempted to assume there is more to this story,
    Someone once said of the Clintons, “the truth is a lie yet undiscovered”. In the case of too much climate research the data upon which a paper’s conclusions are based is the consequence of an adjustment yet undisclosed.

  20. Sigh, why do you get the feeling the error bars on this are so wide you could fly a 747 through them .
    Of course it is not possible for any of the material to moved around in 120,000 so it must be where it was initial laid down. You get the feeling where back to ‘magic tree rings ‘ again .

    • I was thinking how to bring up that point WRT the material not moving. I spent 20 years rock hounding along Crow Creek in the Pawnee National Grasslands between Briggsdale and Wyoming in Colorado. The area receives less than 12″ of annual rain. In an abandoned homestead dump I found a file at least 75 years old that still had its teeth after being exposed to the elements for so long, just to give an idea of the dryness. Over the years I saw an embankment in a ravine wash out and reveal a dozen or more tree stumps a couple of feet in diameter. They were composed of poorly adhering grains and disappeared into sand in a couple of years. In all the years, 4-6 days a week I never saw another human, and the only wildlife other than a few small rattlers (<18") I saw one antelope watching me from a half mile away.
      Anyway, this is pretty flat land with hills that rise 20-30' above the prairie. The prevailing winds are from the NW, and all the hills are oblongs with their wide dimension aligned with the airflow. It appeared to me the hills were probably always moving SE with the wind. The NW end of the hill would catch the wind and material would be blown SE. This would be a slow process. There are rocks protruding above the ground, that are polished from the dust on the wind. That had to take a while too.

  21. ” 70,000 to 55,000 years ago, in the midst of a minor ice age, the pattern of precipitation in North America shifted from one dominated by a west-to-east flow of storms from the north Pacific to a south-to-north flow from the Gulf of Mexico.”
    In other words the climate shifted from more zonal to more meridional. Who knew?/wink. Which of course is exactly what it does when there is a larger temperature gradient between the tropics and the poles. Of course, the ice “caused” this and lack of Carbon dioxide caused the ice.
    Sometimes I think these guys do all their thinking while hanging upside down…

  22. Ok, this makes some sense. The southeast to northwest flow of moisture explains why the great basin contained large deep lakes which diminished and ultimately evaporated at the end of the glacial period. We are getting the story one chapter at a time. If we think about it, the implications for large herbivores and their predators could have been the environmental (why do I hate that word now), anyway, environmental event that explains the extinctions during the same geologic era.

  23. I’d like to see more of this paper, but the paper isn’t available on line yet. There were several previous dating methods from the 1980s that attempted to date carbonate rinds on rocks, some more successful than others. The problem has always been whether the carbonate material and incorporated radioactive materials constitute a closed system or open system (For example see http://pubs.usgs.gov/of/1985/0299/report.pdf )

  24. And all this from one rock! Pine cones are so last week.
    Seriously though when I read “fill in key gaps in the paleoclimate record” I immediately thought “What about checking the bits between the gaps? i.e. independent verification of what we “know” already.
    Sadly, as others have said above, the reputation of climate “scientists” is so poor now that it seems subjectively they would either fall-into-line or fall-on-their-swords.
    I hope they prove me wrong.

  25. “This is a new insight from geologic sources of paleoclimate data,” said Oerter. “The techniques that we developed can now be applied to similar soil deposits to fill in key gaps in the paleoclimate record.
    So they found a gap with little info inserted a little used “new” method of “dust” dating to say there was a Ice age ? I wonder if my wife can date the dust in our house without going to Wyoming, it would save a lot of travelling.

  26. I note these phrases in the article: “…revealing a time in North America’s past when summers were wetter than normal.” and “That atmospheric circulation translated into wetter summers and drier winters in central North America, a reverse of the usual pattern…” These show a bias that what it was like in the 20th Century was “normal” and “the usual pattern”, when actually it is the less common pattern during this time period.

  27. It would be very interesting to see how the results for this period of time fit into the Milankovich cyclicity, the primary driver for these higher frequency glacial and non-glacial periods.

  28. I appreciate this report and I find it fascinating. I’ve been fascinated with the sandstones of Arizona and southern Utah but when my geologist friend described the prevailing winds millions of years ago I thought he was imagining things. But she showed me from my own photos that you can see the slip faces and bedding planes on the ancient sand dunes and from that easily deduce the prevailing winds and climate.
    The fact that a thousand feet of sand accumulated against the central plateaus of Arizona and Utah shows that the prevailing winds came from the east, northeast more specifically, blowing across a vast desert that once had been a shallow sea. This happened many times with different sediments deposited in those shallow seas at each sea-filling, then blown into huge piles of sand that are now different strata, and different colors, of sandstone. The most recent of these probably constitute the sand hills of Nebraska which weren’t petrified under the weight of deposits above them.

    • There are far more sand hills than just in Nebraska, The Nebraska sand hills cover the largest area but there are sand hills all over the west, there are even sand dunes in western Minnesota, Throw in Eastreb Wyoming, Eastern Colorado and West Central Kansas Highway 83 cuts through both Nebraska and Kansas sand dunes, throw all those into that mix. I am certain if you look you will find them in Oklahoma and Texas also At some point in time most of the great plains was a huge desert. Oh by the way the sand dunes in Minnesota were from a lake, one small pond, it only covered parts Minnesota, South Dakota, North Dakota, Manitoba and Ontario, It was lake Agassiz funny I have lived in an area that had in the last 25,000 years was covered with mile of ice, then the ice was replaced with 300 feet of water and then the lake turned into a big swamp, which was drained a little over a 100 years ago and now it is fertile farmland and somehow I supposed to be afraid of of a few degrees of temperature change.

  29. The last phrase in the first paragraph puzzles me. “..wetter than normal.” How do you define normal in this time frame?

  30. An interesting conclusion. If there is a stable weather event such as this how do we explain the multiple advances and retreats of the known glacial activity. Further, how do we now reconcile the oft made claim that there was up to 5,000 metres of ice sitting over the top of the village of New York with the map shown in the article.

  31. Captured carbon stored as age lines on rocks!? Priceless!
    Of course, if this method of weather paleo proxy determination works, i.e. fully verified and independently replicated; carbon dioxide naturally stored as carbonate rings will be the a death knell for state pen hokey sticks.

  32. I seriously have to wonder about this. Between 55,000 years and now, all the surface area of Canada and some of the Northern U.S. has been scoured back and forth by glaciers. Also, the type of weather pattern change from S-N to W-E is pretty similar in many respects to what we see in Western Canada today from summer to winter except that in the West we get southerly flows from the Western U.S. in summer while Eastern Canada is more affected by Southerly flows from the Gulf in summer. In winter, most of Canada’s air flow is out of the North West. If they are saying that the dominant air flow from West to East was not present, I would seriously doubt that.

  33. The map seems to depict Blocksarus Rex being in place on the average for thousands of years. Seeing the predominance of that pattern the past few years should make one take pause. That said, the simplest explanation is normally the best, in this case, PDO is probably the culprit

  34. How does a High pressure system attract moisture from the south? Winds move from areas of high pressure to Low pressure, so the flow should be from the north to the south.

  35. ‘The information will be useful to improve the accuracy of climate models by providing known conditions to calibrate them to.’
    ‘useful’:
    reads to me like Hey AGWers, hope you will learn something here!
    Regards – Hans

Comments are closed.