March 01, 2013

Doubt cast on Tam Pa Ling age

For reference, see the post on the original article:

From a criticism of the original paper:
Hence, contrary to the authors' assertion that TPL1 has a “minimum secured age of 46 ka and a maximum age of ∼63 ka”, the published stratigraphy, if correct, indicates that the TPL1 specimen is no older than 46 ka. TPL1’s status as “the earliest well-dated modern human fossil east of the Jordan Valley” also appears weak compared with the Liujiang specimen dated to ∼153 ka (3), the Callao Cave fossil in the Philippines dated to 67 ka (4), and, above all, the ∼100 ka modern fossil from Zhirendong (5), discovered only 484 km northeast of Tam Pa Ling in Southern China.
Irreconcilable differences between stratigraphy and direct dating cast doubts upon the status of Tam Pa Ling fossil 

Alain Pierret et al.

... and from a reply to the criticism by the authors:
They question the validity of the dating because of an apparent “reverse stratigraphy” (Fig. 1), whereby “older” dates are located higher in the section [i.e., 51.4 (14C) at 2.1 m] and “younger” dates are at the bottom of the section [i.e., 48 ka (optically stimulated luminescence [OSL]) and >49.2 ka (14C) at 4.3 m] (2). This criticism ignores the presented SEs (table 2 and table S1 in ref. 1), which make the results statistically equivalent (Table 1). More importantly, they ignore that the radiocarbon results are well beyond the accepted radiocarbon barrier of ∼40 ka (3), indicating that the charcoal has a minimum age of ∼40 ka. Bearing in mind these problems, we have conservatively estimated the burial age to be ∼46 ka according to the luminescence dating of the sediments. As the luminescence results are stratigraphically consistent, we perceive no irreconcilable differences between the stratigraphy and dating. 
Finally, we interpret TPL1 as the earliest human fossil that is both well-dated and fully modern in morphology. Zhirendong demonstrates a mixture of archaic and modern traits, making it significant but not fully modern in appearance (4). Similarly, the metatarsal from Callao Cave is only diagnostic to the genus Homo given that it falls within “the morphological and size ranges of Homo habilis and H. floresiensis” (ref. 5, p. 123). Although the modernity of the Liujiang fossil is not questioned, it has no direct date and no secure stratigraphic provenance. It has been variably dated to ca. 20 ka, ca. 67 ka, 111 to 139 ka, and >153 ka (6), and this uncertain stratigraphic context has prevented many scholars from accepting any of the dates currently attributed to it (6).

Reply to Pierret et al.: Stratigraphic and dating consistency reinforces the status of Tam Pa Ling fossil 

Fabrice Demeter et al.


andrew said...

The defenders of the study make a better case in regard to both their own find and the others argued to be older, than their critics.

terryt said...

"Zhirendong demonstrates a mixture of archaic and modern traits, making it significant but not fully modern in appearance"

Isn't that what we'd expect in so ancient a 'modern' human?

Anonymous said...

The individual probably is just part of the normal distribution and variation found in Syria. Nothing to do with Kurds, Iranians or Saladin and his harem.

Interesting, one of the administrators of Y chromosome haplogroups at FTDNA said to me that he thought my haplogroup and subclade came from Lebanon. I replies that the Lebanese people today are a mix of Europeans, original Levantines and various immigrations Christian, Muslim from the Arabian Penisula, and of course sub Saharan Africans. They are receivers not givers of diversity. This study shows that very fact. Today's Levantines are similar to each other due to recent mixing with each other, but the original basis is thoroughly mixed.

Unknown said...

Can someone provide the traits that are being used to call this fossil a "fully modern" human? Saw it on First Peoples on PBS last night and from those images it appeared to have heavy brow ridges, almost no cranial vault or forehead and very thick bone. Looked more closely related to Homo Erectus than any "modern" human skull. Please enlighten me on this.