'Peking Man' older than thought (BBC) {new isotope dating method!}

[eppur_se_muova]

By Paul Rincon
Science reporter, BBC News

Iconic ancient human fossils from China are 200,000 years older than had previously been thought, a study shows.

The new dating analysis suggests the "Peking Man" fossils, unearthed in the caves of Zhoukoudian are some 750,000 years old.

The discovery should help define a more accurate timeline for early humans arriving in North-East Asia.
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This method is based on the radioactive decay of unstable forms, or isotopes, of the elements aluminium and beryllium in quartz grains. This enabled them to get a more precise age for the fossils.

The results show the Peking Man fossils came from ground layers that were 680,000-780,000 years old, making them about 200,000 years older than had previously been believed.
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more: http://news.bbc.co.uk/2/hi/science/nature/7937351.stm




Peking Man older than thought (Nature)
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The aluminium/beryllium technique offers new opportunities for re-dating other palaeoanthropology locations, particularly in China where the age of sites is difficult to determine because of the lack of more easily dateable volcanic ash. The method works for samples up to at least 3 million years old.
***
First, the team had to select clear, white quartz crystals that were buried with the fossils, not grey ones that might have been washed in later. This meant tedious grain-by-grain examination of sediment. One student working for eight hours could only isolate two grams of quartz, Shen says.

Because 60–100 grams is needed for each test, Shen says: "I had to mobilize my students to work for weeks, work not so easily conceivable by my US collaborator."

The dating method is based on the radioactive decay of 26Al and 10Be isotopes. While they're on Earth's surface, the two isotopes within the quartz are produced at a known ratio through exposure to cosmic radiation. When sediment buries the quartz, the generation of isotopes by cosmic rays nearly stops. The researchers dated the fossils by determining the isotopic content of the quartz and calculating backwards to work out the ratio of the two isotopes when the quartz was buried.
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more: http://www.nature.com/news/2009/090311/full/news.2009.149.html





This is quite an achievement! Radiocarbon dating is of little use for material older than 60ky. A lot of human prehistory is represented by remains and artifacts older than that.

[Taverner]

1. So - the million dollar question - do you think men evolved in parallel evolution?

That question brings up a ton of other questions - for example, if they did not, then perhaps could we have evolved earlier than had been previously thought?

[Double T]

3. Man has occupied this planet for several million years.

The link below provides interesting new information regarding the existence of man. What I find more remarkable is man's impact on this planet's environments. Man has existed on this planet for several million years yet it has taken only one or two centuries for man to significantly destroy this planet's environments, impact the premature extinction of many species and adversely affect the condition and availability of natural resources.

http://www.philly.com/philly/hp/news_update/20090227_Footprints_offer_clue_on_path_to_modern_man.html

[Taverner]

5. So we spent most of our existence in a Hunter Gatherer state...

Interesting - and it explains so much

[aquart]

9. There was a lot to hunt and gather.

No need to create agriculture or civilization until there's a crisis.

[Taverner]

16. Interesting - let me think about that for a while

[eppur_se_muova]

17. Quite a lot, yes. I'm currently reading "After the Ice", about this period.

Hunter-gatherer societies appear to date back to at lead 200,000 BP. Farmer societies arose (AFAIK) within the last 20ky, but had to start over after the Younger Dryas downturn in temps, so are really <10ky of (pre)history. (Numbers are very rough, off the top of my head, and actually vary from place to place.)

[muriel_volestrangler]

6. I don't think it alters the dates of Homo erectus evolution much

but it does mean they were in China at the same time as the 'Java Man' Homo erectus remains that have been found, rather than being just later.

http://www.scienceonline.org/cgi/content/full/312/5772/361

http://history.howstuffworks.com/asian-history/java-man.htm

[moundsview]

7. The million dollar answer might be

that science is really a moving target. Outside of pop culture and non-scientists, maybe there is no such thing as "settled science". Every day new information comes to light and anyone who is arrogant enough to claim that they know anything beyond a doubt is a fool.

[Taverner]

8. Science being a moving target has already been established

But I do wonder if we were here longer than we previously thought - and if so, what does that tell us about the Hunter/Gatherer culture.

[ChairmanAgnostic]

2. Heathens! Pagans! Devil worshipers! It's only 7,000 yrs old, or else!

Bah on those "scientists" who rely on "science!"
"Science" is hobbled by the fact that it relies on "facts." And since god is awl powerfool, and awl knowing, he can change facts at will. So, that is proof positive that you science believers are wrong, and Faith is the only thing that is correct.

[Double T]

4. Here is your kind of guy. The science of denial.

http://www.answersingenesis.org/tj/v8/i1/erectus.asp

[ChairmanAgnostic]

13. always admired canal builders.

And, by my count, there have been three near de nile, over the last 3 millennia

[ayeshahaqqiqa]

10. Please help this non-anthropologist

Peking Man--was he the one whose fossilized remains were larger than homo sapien sapien? And where in the family tree would he be--a direct ancestor, an "uncle", or a dead end? Thanks in advance for your answers.

[Odin2005]

11. Peking Man was a Homo Erectus.

Modern Humans evolved from African H. Erectus populations, the Asian populations were dead ends.

The tree is something like this:

--->early H. Erectus--->African H. Erectus--->H. Heidelbergensis--->H. Sapiens
*********`---> Asian H. Erectus*********************`--->H. Neaderthalensis

[ayeshahaqqiqa]

12. Thank you so much

From your tree, then, there is a possibility that the Peking Man and the Neanderthals were directly related? Is this surmised because of their slightly larger size than homo sapiens?

[Odin2005]

14. Oh, probably not, the asterisks are just space filling, they don't show relationship.

We and Neandertals both evolved from African and Western Eurasian populations of Homo Heidelbergensis[] respectively about 200,000 years ago.

[TechBear_Seattle]

15. Human evolution is very twisty

You might find this page from the Smithsonian Institute interesting.

As Odin said, modern humans evolved out of an African group of H. erectus; all other early human groups have disappeared, although many existed for far longer than H. sapiens has been around.

[xchrom]

18. our history is really wonderful -- and what

great discovery this is.