This article is reproduced with permission from the magazine Nature. The article was first published on October 18, 2012.
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Climate records from a Japanese lake are providing a more accurate timeline for dating objects as far back as 50,000 years
This article is reproduced with permission from the magazine Nature. The article was first published on October 18, 2012.
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24 Comments
Add CommentRe. Neanderthals, their genes have been found in most non-African populations of modern humans, meaning that there was some coterminous residency and interaction between the two groups of humans in at least some regions that produced successfully reproducing progeny, right? I don't understand how "better dates for any overlap" will help convince those who reject the idea of interaction...
Reply | Report Abuse | Link to thisI first heard about this over 12 years ago. Why has it taken so long?
Reply | Report Abuse | Link to thisIt could be a combination of both climate change and disease.
Reply | Report Abuse | Link to thisAnyone who still doesn't believe that Neanertals & modern humans interacted wil probably ever be convinced. What better carbon datng may be able to prove is whether the Neandertals' decline began before or after they started encountering moderns, thus giving us better idea whether moderns were the main driver of Neandertal extinction or just the last nail in the coffin.
Reply | Report Abuse | Link to thisWould the newly calibrated carbon clock only be accurate in the area of Japan? There are a number of things that can cause variations in the atmospheric content of carbon-14, many of which could be local. Forest fires, eruptions, specific animal populations generating methane in the local area would have an effect.
Reply | Report Abuse | Link to thisSo this would only give a somewhat more realistically accurate clock not a perfectly accurate one.
Another wonderful example of the how the dialog of science, as opposed to the musings of the faith-based, moves our knowledge of the world, both past and present forward. This dialog is created by dedicated folks in the field... often doing mundane but critical work.
Reply | Report Abuse | Link to thisImagine examining 70 meter sediment cores and meticulouly counting the layers... over 100,000... to get past 50,000 years! All this just to refine the precision of C-14 dating by perhaps a few hundred years at that benchmark.
The Neaderthal question is interesting... but not critical in my view, because as with any extinction event of a hominid specie, i suspect several factors must have been in play.
Kudos to the scientists that keep on... keepin' on!
Oh, and considering the lake being so close to a volcano (Mount Fuji), the clock could be very biased by local conditions.
Reply | Report Abuse | Link to thisThe text is correct in stating that lake Suigetsu is West of Tokyo, but so is China. Mt Fuji is nearly 3 times closer to Tokyo than it is to this lake, which is on the opposite side of the island, nearly on Wakasa Bay in the Sea of Japan. Mt. Fuji is not likely to have impacted the lake Suigetsu sediments.
Reply | Report Abuse | Link to thisSpin-oza - As I understand, previously carbon decay rates had only been calibrated to around 12,000 years ago, so the new ~50,000 year old calibration provides a enormous extension to C-14 dating precision for dates older than around 10,000 years ago.
Now wait just a cotton-pickin' minute! Fifty THOUSAND years can't be right. That's like 42,000 years before Adam & Eve. There must be a serious mistake in your "scientific" theory, because it sure doesn't fit in with the REAL theory of creationism...
Reply | Report Abuse | Link to thisOK, just kidding! I enjoyed the article greatly.
Good joke! Be sure to throw in a reference to Todd Akin the Magic Vagina Guy for authenticity!
Reply | Report Abuse | Link to thisYou are over estimating the impact of those events on annual accumulations. Also, things like forest fires and volcano's leave other telltale markers. Furthermore, the radiocarbon used in this process is created in the upper atmosphere by solar radiation, not in volcanoes. And finally, these finding are cross referenced against other findings, such as ocean cores, sea shells, tree rings, etc. so it is a process of refinement. One of the reasons this lake is such a good lab is because it is pristine. There are very few rivers that feed the lake, which suggest it is at a high altitude, so accumulations are from seasonal changes to the lake and the biota around the lake almost exlusively. No one claimed that the results would be perfect, just better than what we currently have. And in that regard, the calibration changes to radiocarbon dating are rather small. Very few things in the real world are perfect (maybe beer). Science is about probabilities and the gradual refinement of theories.
Reply | Report Abuse | Link to thisHow interesting! What a pity I do not have more time to dig into Earth Sciences. Carbon dating is more Chemistry than Earth Science probably. This article creates some little doubts in my mind. I thought carbon dating was very precise. Now that you mention that living things incorporate carbon 14 while we are alive but the quantity of carbon 14 varies according to conditions in he atmosphere or in the environment the whole game seems to change. If the error is around 100 years in 50,000 years does not seem to be much of a problem. But what happens if we want to date an event millions of years ago. Looks like we are losing a measurement tool to precisely date back events that happened millions of years ago. Probably there are other measurement tools beside carbon 24. Well we are not geochronometrists. But we of course are very interested in this matter. It is interesting that the article only mentions events in the not so distant past. Will many corrections will be required? It is very important to continue keeping an eye on this matter for a more full updating of the subject matter.
Reply | Report Abuse | Link to thisWell, commentaries from RSchmidt are very interesting and clarify some of my doubts. We should support universities an scientists (and scientific publications) for continuing research. At the same time we should continue digging in our own fields of endeavor no matter how difficult sometimes it becomes. The more difficult it becomes the harder we push ahead until we hit pay dirt.
Reply | Report Abuse | Link to this“The problem, says Bronk Ramsey, is that tree rings provide a direct record that only goes as far back as about 14,000 years.”
Reply | Report Abuse | Link to thisI don't understand this sentence. Does it mean the oldest tree just lives for 14,000 years?
And I don't know the relationship between carbon date and tree rings.
As I understand, the carbon-14 content fixed in the dead wood within a ring of a living tree can be independently correlated to specific date by counting rings. That provides a sample of the carbon decay that has occurred since that independently confirmed year.
Reply | Report Abuse | Link to thisHowever, I'm not certain I understand very well, having read through
http://en.wikipedia.org/wiki/Radiocarbon_dating
It includes a (somewhat confusing) discussion about calibrated and uncalibrated carbon estimates...
I did learn one thing that I think is commonly misunderstood: the (at least proper) definition of 'years Before Present (BP)' refers to 1950 as the 'Present'...
Because the half-life of carbon-14 is some 5,700 years, it is only reliable for dating objects up to about 60,000 years old. Evidently, the tree ring records were the most accurate way we had to calibrate the "carbon-14 clock," before the work described here.
Reply | Report Abuse | Link to thisMy understanding is that, even though individual trees may live at most 3,000 years, but more commonly several hundred, there is a fossil record of many different trees whose lives overlapped over a long period of time. The overlap can be matched up by comparing growth rings. For instance, the last 50 years of one 2000-year-old bristlecone can be aligned with the first 50 years of another. This kind of matching can be carried back for about 14,000 years.
Reply | Report Abuse | Link to thisSlight correction: The top age for a bristlecone pine (an Intermountain bristlecone, if memory serves) is almost 5,000 years.
Reply | Report Abuse | Link to thisAmazing how much additional information you can get from the comments. I am curious though as to how far back peat bogs have collected carbon. Can they be differentiated in layers or correlated to years as well? Seems they keep finding ancient bodies in those places.
Reply | Report Abuse | Link to thisOr course some of those peat bogs were covered up and eventually turned into coal but it may be difficult if not impossible to get anything approximating a continuous range of years into the past.
Plain-2009 said:
Reply | Report Abuse | Link to this"But what happens if we want to date an event millions of years ago. Looks like we are losing a measurement tool to precisely date back events that happened millions of years ago."
Carbon-14 (not 24) dating is not used for dating fossils for the simple fact that fossils no longer have carbon. The organic material has been replaced by minerals. The stone fossils are dated by other means.
It is indeed odd, that most European hats, (Borsalino etc.), seem to be made for round headed humans, while both Dad and I, with ancestry linked to Scandinavia, have much more oval skulls, and we wear those hats, at our discomfort, and lose hair, due to the shape, which is too round.
Reply | Report Abuse | Link to thisThe Homo Sapiens are always represented as having a more round head, whereas, a longer skull seems to suggest that either Neaderthals also evolved, or mated with the other hominids, and did not die out and were assimilated, or the reverse.
I wonder if the pre-flood water canopy had an impact on carbon-14. http://www.amazon.com/The-Waters-Above-Earths-Pre-Flood/dp/0802491987
Reply | Report Abuse | Link to thismakes a scientific argument for the canopy referenced in the bible
@SteveMont
Reply | Report Abuse | Link to thisDo remember that in Biblical geochronology, the length of the day is a highly variable factor, allowing for convenient adjustment of chronological data as needed. As needed? As needed for what? Well, as needed for .... hmmmm.
This new study assumes the consistency of "Two distinct sediment layers have formed in the lake every summer and winter" without much disruption or change in frequency for a period of "tens of thousands of years" although some of the leaves deep in the layers "look fresh as if they’ve fallen very recently."
Reply | Report Abuse | Link to thisInteresting.