A critique of the chronometric evidence for hominid fossils: I. Africa and the Near East 500–50ka

Abstract

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThe chronometric dating evidence for all hominid fossils from Africa and the Near East that have previously been dated to 500-50 ka is critically assessed using the concept of chronometric hygiene, and these dates are revised using Bayesian statistical analyses where possible. Sixteen relevant hominid sites lacking chronometric evidence are briefly discussed.Chronometric evidence from 37 sites is assessed in detail. The dates for many hominid fossils are poorly constrained, with a number dated by comparisons of faunal assemblages a method that does not have good chronological resolution for much of the last million years. For sites with stratigraphic sequences of dates, it is generally possible to refine the dating, but in some cases, the revised chronology is less precise than previous chronologies. Fossils over 200 ka in age tend to be poorly dated, but for the last 200 ka, dating is better due to the availability of electron-spinresonance and thermoluminescence dating. Consideration of the chronologies favored by the proponents of the out-of-Africa and multiregional hypotheses of human evolution shows their selectivity. The chronological assessment of the fossils here is compatible with either hypothesis.If evolutionary schemes that do not rely on the morphology of the hominid fossils to decide the sequence of fossils are to be built, then further dating is required, alongside full publication of existing dates.3

New radiometric ages for the Fauresmith industry from Kathu Pan, southern Africa: Implications for the Earlier to Middle Stone Age transition

“…In the Middle East, blades are found in the Amudian industry of the Late Lower Paleolithic. The dating of this industry is the subject of debate based on discordant ESR ages (on teeth) which place this industry in OIS 7 (186-245 kyr), as opposed to TL ages (on burnt flint) which place the Amudian in OIS 9 (Porat et al, 2002;Barkai et al, 2005;Millard, 2008).…”

“…In the absence of dated fossil hominins from southern Africa coeval with the KP-1 Fauresmith, this assemblage remains bracketed by the Saldanha (Elandsfontein) skull, attributed to Homo heidelbergensis or archaic Homo sapiens (Klein et al, 2007;Rightmire, 2001), associated with Acheulean artifacts and dated by faunal associations to ca. 320-790 kyr (Millard, 2008) [or 600-1,000 kyr (Klein et al 2007)], and the Florisbad skull associated with MSA artifacts, usually attributed to early archaic Homo sapiens and directly dated by ESR to 259 AE35 kyr (Grü n et al, 1996;Rightmire, 2001). The KP-1 ages clearly demonstrate that the advent of blade production predated the appearance of modern Homo sapiens in Africa, as attested to by the Kibish Formation fossils with an inferred age of 195 AE 10 ka and the Herto H. sapiens dating to 160 AE 4-154 AE 14 ka (Millard, 2008 and references therein).…”

The origin and evolution ofHomo sapiens

“…Nevertheless, we have to work with what is available, and I will now briefly discuss the most complete or significant specimens discovered so far, region by region (figure 1). Wider and more detailed compilations on the material and its dating can be found in Schwartz & Tattersall [32], Millard [33], Klein [34] and Wood [35].…”

Correlation of the KHS Tuff of the Kibish Formation to volcanic ash layers at other sites, and the age of early Homo sapiens (Omo I and Omo II)

“…Notwithstanding Millard's statement, other workers have taken his statement to mean that the age of Omo I and Omo II is not known better than these limits (e.g., Endicott et al, 2009;Cartmill and Smith, 2009), reinforced by Fig. 4 in Millard (2008). Other lines of evidence presented previously have been ignored.…”

“…It was also suggested that the lower part of Member II was most likely deposited at w172 ka, providing a narrower bracket for the age of the fossils. Millard (2008) reevaluated the laser fusion ages on these units, and concluded that the limits that can be placed on the hominin remains are "189.6 AE 1.4 ka (sample 02-01B) and 99.8 AE 1.0 ka (sample 99-274A), but actually lie much closer in time to the former" [Emphasis ours]. Notwithstanding Millard's statement, other workers have taken his statement to mean that the age of Omo I and Omo II is not known better than these limits (e.g., Endicott et al, 2009;Cartmill and Smith, 2009), reinforced by Fig.…”