|Affiliation(s)||PI||Project period||Funded by|
|DEES||Berger, Glenn W||06/01/2009 - 05/31/2011||National Science Foundation|
Keywords: Spain, caves, hominid, fossil tools, IRSL, luminescence, dating
Right: Dr. Berger collecting sediment from the Galeria karstic infill cave in Spain. Also, Skull fragments, probably about 0.95 million years (Ma) old based on TL dating, from the nearby Gran Dolina site.
Until about 1995 it was thought that protohumans (hominins) began leaving Africa by ca. 1.8 Ma, but not a single bone or undisputed tool site older than c.500 ka was identified in Europe. Since 1995, hominin bones and tools found in one bed (TD-6) at the Gran Dolina limestone-cave site, Sierra de Atapuerca, have been shown to be older than 780 ka (ka = thousand years), based on paleomagnetic data. This is now the site of one of the oldest hominins and stone tools in Europe (2007 discoveries at another site nearby at Atapuerca are older). At Gran Dolina faunal remains (including hominin) and lithic artifacts are also found in several successively younger strata, but these strata are not directly dated. At the nearby cave site of Galeria are more faunal remains and a few dates (by ESR and U-Th) younger than 350 ka at three horizons, plus the 780-ka paleomagnetic boundary in a lower stratum. Because of the paucity of suitable dates, correlation of the younger-than-780-ka parts of these two sites is speculative. Moreover, the specific chronological development of hominin presence at this key European location (Atapuerca) has been unknown or poorly understood.
This project applied photonic dating (the feldspar-specific infrared version, IRSL) and thermoluminescence (TL) dating to cave strata at Gran Dolina and Galeria to cave deposits ranging upwards from ca. 100 ka. This is a sensitive means of dating the last exposure to daylight of small feldspar grains in the cave sediments. The initial project results represent the first application of luminescence sediment dating to such karstic-infill cave deposits anywhere, and help place the fossil remains and tools more accurately within the broader temporal context of known development of hominins and fauna elsewhere in Europe and the world.
Remarkably, at Gran Dolina TL was able to provide an accurate date of ca. 900 ka for sediment below the 780-ka magnetic reversal boundary, and above the oldest hominin fossils. Thus these hominin remains are probably about 950 ka old, making them among the oldest human ancestors in Europe. (see also Berger, G.W. and A.P. Gonzalez. 2000. J. Human Evolution, v.38(3), p.A6-A7; Berger et al., 2008, J. Human Evolution, 55, 300-311); Dennell and Roebroeks, 2005, Nature, v. 438, p.1099ff, and http://www.atapuerca.com or 'google' the word 'atapuerca').
Project Image Gallery
Click on a thumbnail below to see an enlarged image.