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Carbon Dating Gets an Update
ananyo writes "Climate records from a Japanese lake are set to improve the accuracy of carbon dating, which could help to shed light on archaeological mysteries such as why Neanderthals became extinct. Carbon dating is used to work out the age of organic material. But the technique assumes that the amount of carbon-14 in the atmosphere was constant — any variation would speed up or slow down the clock. Since the 1960s, scientists have started accounting for the variations by calibrating the clock against the known ages of tree rings. The problem is that tree rings provide a direct record that only goes as far back as about 14,000 years. Now, using sediment from bed of Lake Suigetsu, west of Tokyo, researchers have pushed the calibration limit back much further. Two distinct sediment layers have formed in the lake every summer and winter over tens of thousands of years. The researchers collected roughly 70-meter core samples from the lake and painstakingly counted the layers to come up with a direct record stretching back 52,000 years. The re-calibrated clock could help to narrow the window of key events in human history. Take the extinction of Neanderthals, which occurred in western Europe less than 30,000 years ago. Archaeologists disagree over the effects changing climate and competition from recently arriving humans had on the Neanderthals' demise. The more accurate carbon clock should yield better dates for any overlap of humans and Neanderthals, as well as for determining how climate changes influenced the extinction of Neanderthals."
The problem is that tree rings provide a direct record that only goes as far back as about 14,000 years.
What's the problem? That's 7,984 years before the beginning of time.
Sheesh, evil *and* a jerk. -- Jade
...they dominate U.S. politics!
Holy crap. "Painstakingly" doesn't even begin to cover counting 52,000 stripes in a core sample.
Aren't you curious what God was up to before genesis? I mean, if God has existed forever, and the universe is just 6000 years old, then what the hell was he doing all the rest of that time? Off making other universes? Were they successful or not? How much baggage does God have? Are the angels the result of those previous geneses? If not, when were the angels created? And the cherubs, oh why won't anyone think of the cherubs?!
The theological implications of this new science are infinite and staggering.
Science is all about firing a drunk pig out of a cannon just to see what happens.
Maybe if you knew what a half life was you wouldn't find it so confusing?
Wouldn't the amount of C-14 have been the same for humans and Neanderthals at any given time? Therefore while we may be unclear exactly when they went extinct (presuming Bigfoot is not a surviving branch of Neanderthals), we should have a pretty good idea in the overlap. Unless they use different dating methods for different events, this really shouldn't change the general picture.
I'm amazed that they found a clear seasonal pattern in a lake going back 52,000 years. Lakes are short lived structures, geologically speaking and 52,000 years is quite far into the last ice age. I guess the lake somehow managed to avoid being glaciated and managed to avoid being washed away by the melt waters. Impressive! I haven't located an ice age map of Japan so I don't know how much, if any, of Japan was actually covered by ice. It is far enough North but the ice sheet was not uniform. (Parts of Alaska were ice free)
I'm not sure what you're trying to imply here. What "they want" is the most accurate answer our CURRENT tools can provide. And as the margin of error of the tools gets reduced over time, they measure again. Trying to narrow down our accuracy doesn't exactly scream "hidden agenda" to me.
Christ! I can appreciate the desire to really dial in our techniques, but expecting that after only about a half a century of refining these techniques that we know the difference between 10,643 and 10,633? We're impressive creatures but it sounds like you're holding out for Doctor Who to swing by and show you history.
Really, it's the best tool we've currently got, and you don't throw out the best tool you've currently got in favor of eyeballing it. Looking at the current margin of error and throwing carbon dating out is throwing the baby out with the bath water.
Maybe if you knew what a half life was you wouldn't find it so confusing?
His comment doesn't show that he doesn't understand the concept of a half life.
I'ts a superficialy reasonable question - if we know that C14 is decaying then it must of come from somewhere.
But his error is to assume the only place it could have come from is the decay of something else.
In fact it's generated by cosmic rays hitting Nitrogen, a beta particle (electron) is captured by N14 giving C14.
Watch this Heartland Institute video
The last magnetic reversal of the poles was 780,000 years ago, 720,000 years before carbon 14 dating is useful. I doubt it has any effect.
The Internationally agreed Radiocarbon calibration curve (IntCal) - co-ordinated from Belfast University - takes info from ice-cores, lake sediment cores, tree-rings, corals, etc from the Southern and Northern hemispheres (there's an offset between them) puts them together (this work is done by statisticians using specially developed methods rather than other scientists using off-the-shelf techniques) and although some scientists would rather that only their work was used (as they can then claim whatever 'accuracy' they wish to claim) independent verification of lab practices is extremely useful in the work. The most recent published work dates back to 50,000 years BP ('before present' where 'present' is 1950) and the next set of curves (IntCal 12) - being worked on at the moment will take it back further. Abstract for IntCal 09 - http://eprints.whiterose.ac.uk/10694/
That carbon dating has always been as accurate as you can afford. You decide the date that you need in order to confirm your thesis, send your sample to as many labs or as many times as your budget allows, then pick the closest answer from the essentially random set of results.
Anyone on the inside of the inside care to confirm or refute that?
I'm not on the inside, but I've read some of the papers.
Every few years there is an International Radiocarbon Intercomparison, where a batch of different types of samples are sent to most of the world's labs (~100) to date. The results are then compared. Overall stats are published anonymously, and individual labs can publish their results if they want.
The most accurate method (AMS) shows error rates of ~1%, while older methods give error rates of up to 10%.
Of course there are some classes of samples which present special problems; the study samples are ones which don't present major contamination issues.
The full study from 2003 is open access: here
Not correct, absorbing an electron would not change the atomic number. N14 absorbs a thermal neutron, and C14 decays by beta decay. K capture emits a neutrino.
Fugue for Aaron Swartz
Usually when I see a post moderated as informative, it leads me to believe it may contain information of some kind. I think this would be better characterized as insightful.
If anyone does't understand what the parent is talking about, the half-life of Carbon 14 is 5,730±40 years. That means that 52,000 years is a little more than 9 half-lives. By taking 1/2 and raising it to the power of 9, we can conclude that about 0.2% of the original carbon 14 will remain in the oldest layers of sediment.
As for the question of where the Carbon 14 is coming from, we know that it's formed by cosmic radiation striking the atmosphere, and that the amount in the atmosphere varies slightly from year to year. As this article has explained, the purpose of this research is to get a better idea of how much Carbon 14 was in the atmosphere every year so that we can get a better idea of how old a piece organic matter might be based on it's isotopic ratio (the fraction of the carbon that is Carbon 14).
Since the decay of fission products produces thermal neutrons, some of these can be absorbed by the very common N14 to become C14. Above ground atomic tests produced a spike of C14, for example.
Fugue for Aaron Swartz
I'm in! Should I bring flowers and candy?
The Hebrew word for day used in the genesis is account is “yom”, which is a definite 24-hour period.
If a day is an era, why are an evening and a morning even mentioned?
Adam was made on the sixth day (Genesis 1:26-31) which was supposedly thousand of years long. This was followed by the 7th day which was also thousands of years long. Following the 7th day, Adam fell into sin and was expelled from the Garden. This would make Adam Thousands of years old, but according to the Bible he was around 900.
How about: The passage is a parabole for mans fall from grace not literal in any way?
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"Anyone on the inside of the inside care to confirm or refute that?"
how do you refute nonsense?
While lab shopping does happen, it's onyl good for that ONE event and doesn't hold up over times.
If your thesis runs counter to C14, BUT goes along with current understanding of the field, then you have made a huge discovery. Far more important then the thesis itself.
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