Exploring abrupt climate change induced by comets and asteroids during human history

19 Responses

  1. We’ve got a lot of them in the county museum. Came out of a quarry. I’m going to help man a stall in a couple of weeks time with a lot of Pleistocene stuff from the museum vaults. Amazing the things you get to do when you are retired.

  2. Yeah, the radition spikes in trees rings dated to AD 775 and 994 have been used to correct the ice core chronology during the 1st millennium AD. The radiation is likely to have come from intense solar storms/flares rather than supernovae or gamma ray bursts, as argued by the Beryllium 10 spikes in ice cores. The Beryllium 10 was formed at the smae rime as radiocarbon, the former precipitating upon the ice sheets, the latter being taken up by trees. So by comparing the age of Beryllium 10 spikes in ice cores with radiocarbon excesses in precisely dated trees we can in principal accurately date volcanic events and tephra within ice cores, by synchonising the two chronological records.

  3. Question for Jonny – how many more of these events have you guys come across in in the ice cores / tree rings? Cheers –

  4. “The distinct spikes act as time-markers like secret clocks contained in timber, papyri, baskets made from living plants or other organic materials, says the paper published in the Royal Society Journal Proceedings A.”

    Skeptical am I, about dating papyrus and baskets from C14 spikes. Papyrus paper is made from a fast growing reed. And I am sure it is made from different plants with different ages, but young ages. I don’t get how they can nail down solar flares. It’s also made in two layers, recto and verso – crossways and lengthways – which can obviously come from two different plants. I am probably wrong on this, but my first impression is skeptical. How could they possibly date it, OTHER THEN C14? You can’t use C14 dates to calibrate C14 dates.

    Baskets – same argument.

  5. 1.) The C14 dates are more precise than the archeological artifacts that these people want to use to calibrate C14. I think they are working BACKWARD. The advent of C14 meant that the relative and qualitative (and often subjective as HELL) dates could be replaced by something quantitative.

    Now these people seem to be wanting to go back and use the questionable dates of artifacts to re-engineer C14 dates?

    Take a lokok at the WOW in the C14 calibration curves, and you will see that the ranges are SMALL – especially at dates only 1000 years old.

    2.) “The problem, however, is that the tree-ring data is only available in blocks of decades rather than year by year. The paper proposes a cutting-edge mathematical method to filter out particular years within such a block when ‘change points’ in radiocarbon levels occurred.

    NONONONONONONO “Cutting edge” means untried and speculative. NONONONONONO

    And this “decade” thing – what is THAT all about? A C14 date comes back from the lab with a single number age and a +/-. WHat is this about decades?


    My NONONONO bit is because they are going to massage the raw data out of existence and replace it with a PLAYED-WITH date, statistical and methodology being balderdash. I want to see them accurately pick a year out of a ten-year span 100 times out of 100. I will bet they miss 75% of the time.

  6. Sorry guys. I come from engineering, where methods work 10,000 times out of 10,000. Stats? When stats came in, science went out.

    Stats are the only way soft sciences like psychology and such could find to quantify anything they do. So, by taking test populations and such, they do a statistical massage on the data and come up with something that they claim is 95% going to give the same answer. Then they tell us that when some condition had an increase from 0.9/1000 to 1.2/1000 they tell us in screaming headlines that this thing is going pandemic on us because of a 0.3/1000 rise, which they headline as “A 33% RISE! OH MY!”

    This thing sounds like an archaelogical power play to take back primacy from the C14 REAL SCIENTISTS. Arkies are HISTORIANS – who pretend that they are scientists, because they put string grids across a dig and tell us that artifact X321a was found at level -0.923 meters and at grid A15/B23. Logging things and tabulating things doesn’t make them scientists – it makes them archivists. At best. But when they interject their OPINIONS and BIASES, Katie bar the door – nothing is solid once they do that, and science goes out the door, in the back alley where the garbage bins are. When 100 arkies can have 125 different opinions about something, it isn’t science. It’s historians squabbling over the number of angels on the head of a pin. POSERS. And now the posers want control again?

  7. Here is THE IntCal13 calibration curve. Check out the range on dates around 1,000 yeara ago.


    994 AD? I don’t see a spike at 994 AD.

    775 AD? There is enough WOW in the calibration curve that even though it goes flat there, there was a big DIP just before it, and for 100 years on either side it is a roller coaster ride. And that flat is like a considerable number of other flats in the curve.

    (Remember that Richard Firestone got into all of this originally because he was trying to resolve what caused spikes in the C14 curves – which essentially are DATA curves.)

  8. Steve,
    “And this “decade” thing – what is THAT all about? A C14 date comes back from the lab with a single number age and a +/-. WHat is this about decades?”
    The decade thing comes from the radiocarbon calibration graphs. When they state in the article
    “The problem, however, is that the tree-ring data is only available in blocks of decades rather than year by year. The paper proposes a cutting-edge mathematical method to filter out particular years within such a block when ‘change points’ in radiocarbon levels occurred.”
    This is true. The radiocarbon calibration curve is constructed not by the radiocarbon dating of contiguous individual tree rings, but rather by the dating of blocks of 5 or 10 tree rings in succession. While it would be fantastic to have a calibration curve consisting of contiguous annual sampling from all tree ring records, the practice is prohibited by time and cost. So a single data point on the curve is equivalent to the mean age of the mid-point of the 10 year block of tree-rings.
    You are mostly correct though that when you date a sample, the lab will return a radiocarbon age with a +/-. Using this age and uncertainty you then compare it to the radiocarbon calibration curve to find its real age range. For some points of the curve the real age range can be large and you can sometimes get occasions where the age range can extend over two or more non-overlapping time periods, by which you can then assign a statistical weighting, or confidence interval to each age range.
    With regards the detection of the two events at AD 775 and AD 994. These were detected by looking at the delta 14C data. The period containing the AD 775 event was initially detected because of previous studies that highlighted 3 periods of radiocarbon enrichment (two of which had been investigated but the increase was not dramatic over a single year, the latter being the AD 775 period which had a sudden increase between 774 and 775). To put it into context, the AD 775 event is the largest rise in radiocarbon in the last 3000 years. I had seen the same step result in the data obtained on Irish oak in radiocarbon lab in Queen’s University, Belfast some time before the Japanese cedar results were published in Nature. The Japanese had rightfully beaten Queen’s to the punch.
    The AD 994 event was detected solely on the basis of looking at the delta 14C data period AD 605-1015 at annual resolution. The AD 994 event is much weaker than the AD 775 event (about 60% weaker), which may explain why it is not as obvious in the coarse decadal IntCal data.
    If we can probe the radiocarbon curve at annual resolution through the entirety of human history, what other events might we find? Hence the proposal in the recent paper for a Gaussian analysis of the radiocarbon curves to try to tease out some information in lieu of annual resolution data.
    With regards the most recent paper, the proposal for anchoring dates is quite straight forward. The first step is the most difficult and requires the identification of sudden radiocarbon excess events in the tree ring record. This is essentially the same as identifying the events in the radiocarbon calibration curve. So ideally this would be achieved by radiocarbon dating contiguous annual rings. As mentioned before, while desirable it is not practical to do this, hence why the proposal of using statistical methods to tease out possible events from the radiocarbon calibration curves. Having identified (and presumably confirmed that such an event is real through annual dating at these points), we then require archaeological samples to test. Ideally these would be samples consisting of a series of annual horizons (i.e. wooden timbers), a one of sample of mixed aged materials would not cut it. So you would find the approximate age of the sample (through approximate radiocarbon dating). If it happened to bracket (or be near to a sudden radiocarbon event), you could then examine each annual layer and ascertain if it contains the same radiocarbon excess. If it does then one can then precisely date that layer. In fact the Gaussian approach seems to identify periods of periods of radiocarbon depletion (or inert carbon enrichment), so even this could be used as a dating signature in principal. As an example, the Gaussian model has identified a possible depletion in 676 BC, and an enrichment event in 656 BC, so if one were to find a piece of timber that has 50 rings and dated to around this time period, one might date the individual rings and find the depletion-enrichment signature and then determine when the last ring of the sample grew and hence get a precise (and hopefully more accurate date) than radiocarbon dating (even by wiggle match) could provide. Well that’s the dream.
    Indeed, Mike and I are looking at some of the dates that are mentioned in the paper. If you email me your email address I can supply the papers for you ([email protected]).

  9. Agimarc

    I am not aware of any other sudden radiocarbon excess events other than what has been highlighted in the literature, which at this moment in time consists of the confirmed events of AD 775 and AD 994. The goal of course is to try to find more since this would help to synchronise ice core and tree ring records, as well as better dating of history where in some cases historical documentation records possible celestial events.

  10. @ Jonny. Steve Garcia has provided a link in his last post above. I’m interested in the page-3 (all of it), particularly in finding dates 2200bce, 2354-2345, and 3195bce. I see a correlation with C14 BP axis but the others are ???? (and when is exactly BP there?)

    @ Steve G: You have a home-page for that link?

    Thanks all.

  11. @ CR,

    BP means “Before Present”, but in the radiocarbon world “present” is defined as the year 1950. This is why 4000 calBP is 2050 BC.

    The horizontal axis is known as “cal BP” (or “cal BC” for the top horizontal axis), that is the calibrated or true calendar date which we know (particularly in this part of the graph) from tree-rings, since the calibration curve is simply the comparison of the radiocarbon age of a sample of precisely known age.

    The vertical axis is the the radiocarbon age of any given sample.

    The colour data points are the different data that makes up the curve. The black lines define the standard deviation of the data, and as such represent the uncertainty in the calibration curve measurements.

    So if you want to know the true age and hence date of an artifact you would radiocarbon date it and get an 14C BP age. You would then find this value on the vertical axis, then move horizontally until you reach the black lines of the curve, then read of the calibrated age on the horizontal axis.

    As an example, say I got an age of 4300 14C BP for a sample, I would see that this hits the black lines at around 2900 BC. However, you will note this example gives a nice accurate result since the curve is quite linear at this point, but if you were to find the radiocarbon age to be 4500 14C BP, the result would be less accurate since it falls in a part of the curve that is quite flat but with much variability, so the date could be between around 3100-3350 BC. In some cases you could even get two (or more) ranges of dates.

    These are simplified examples, and the practice it a bit more complicated, since the actual radiocarbon age will have an uncertainty +/- with it, which means you have to consider the whole range of radiocarbon age and determine where it meats the curve.

    The link that Steve provided is from the IntCal13 resource page of the journal Radiocarbon. It can be found here http://www.radiocarbon.org/IntCal13.htm. The first link provides the graphs that Steve linked to. The second link provides the data (the black line) for the IntCal13 curve, which you can download, and open in excel or any other graphing package and plot the curve yourself. The other links are different calibration curves for marine samples, and for the southern hemisphere.

  12. @ Jonny, Thank you for the extensive clarification. It was very helpful.

    A second question please. Would there be a complementary chart of ‘tree ring growth indices’ that would extend from say 1000bce to around 5000bce? I have a section (from a pdf file) for 3000-3250bc, a period of interest, plus your paper provides for a section 2300-2400bc. Comparing those to the C14 cal chart for the same eras look like a promising exercise.

    Thanks again and regards to all.

  13. @ CR,

    there are quite a few databases of tree ring data online. You can find data on these these links





    The raw data for the Irish oaks is published in raw form on the web somewhere (I dont know where I am afraid), and would require reconstruction. The Larrsons have made an attempt at reconstructing the belfast data and so you may find the belfast oak data on their site here http://www.cybis.se/forfun/dendro/hollstein/belfast/index.php?PHPSESSID=91d4eb3cf38ee863e68c9727ab9dcbd5#TheIrishData

    A word of caution about that site though. The Larssons are advocates of “phantom time”, that is they think that history is much shorter than what is accepted, and so are trying to falsify some of the tree ring chronologies during particular epochs.

  14. We are getting bombarded (well, very nearly):

    GIZMODO — Another Previously Undiscovered Asteroid Just Buzzed Past Earth for the Second Time in Two Weeks – Ria Misra/Sep 8, 2016

    Astronomers have discovered a new asteroid—just in time to catch it as it hurtled past us at less than a tenth of the distance between us and the moon. It’s the second time that’s happened in two weeks. What have we done to anger you, space gods?

    This most recent asteroid, 2016 RB1, was both slightly smaller and slightly closer than 2016 QA2, the other undiscovered asteroid
    that brushed by us at the end of August. Still, their specs are pretty similar. 2016 RB1 measured in at somewhere between 25-50 feet and came by us at a distance of 25,000 miles yesterday

  15. George, I am not posting much now. I responded to that guy. Sorry for wanting to be clear.

    It is not my fault nobody else is posting.

    But maybe you think it is.

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