Atapuerca, Spain-March 2006
This site was found quite by accident when a cutting for a railway was built through the Cretaceous (80100 Ma) limestones of the Sierra de Atapuerca in the 1860s to transport coal. A cave named Sima de los Huesos (Bones Pit) packed full of bones was unearthed and the site was raided for many years by visitors in search of a ‘souvenir’ such as a bear tooth.
Systematic excavation of the site did not begin to take place until the railway line was closed down in the 1960s. There are Tertiary deposits and Quaternary alluvial deposits above the limestone. The site was declared a UNESCO site in 2000 and is now well fenced in with visits only by appointment.
We heard about the site when we visited Burgos, in Northern Spain and after hearing about possible visits the receptionist at our hotel kindly arranged for us to be added to the list. We duly turned up at the appointed meeting place (about 25km to the east of Burgos) and after checking (several times) in our best Spanish that we were indeed in the right place, we waited for the bus that would take us to the actual site. During our short visit of about an hour we walked along the old railway cutting and saw three sites, Sima del Elefante (about 1 Ma), Galeria (400 ka to 200 ka) and Gran Dolina (1Ma to 220 ka) as well as a cave similar to the Sima de los Huesos.
Here were palaeontological careers in the making. About 25 PhDs have already been awarded for research on the sites. The fauna and flora found in the levels provide a wealth of information about the ecosystems and food available. Teeth have been studied for information about diet, and bones studied for diseases and nutrition. Each site is being carefully excavated in square metre sections a few cm deep. There was no excavation taking place during our visit on a Saturday in November but in one of the photographs in the literature about the site we counted about 40 people working in a small area about 15 m square. Substantial scaffolding has been erected from which researchers can work safely without disturbing the fragile alluvial deposits.
In the Sima del Elefante, elephants as well as rhinoceros have been discovered. Stone tools more than 1 Ma have been found and it is hoped that more finds will describe the type of hominids who first inhabited the Sierra de Atapuerca.
In Galeria numerous animal fossils such as bears, lions, rhinoceros, bison and deer have been found. In addition a small skull fragment and part of a mandible have also been found. The most interesting and controversial discovery has been made at Gran Dolina. Nearly 80 fossils of cranial, facial and mandible bones of at least 6 individuals were excavated in the 1990s. The researchers considered this to be a new hominid species and named it Homo antecessor , dated at more than 780 ka (using palaeomagnetic dating by examining the Earth’s magnetic field reversals).
Parts of the face look completely modern and others look similar to H egaster, making it the last common ancestor of both modern humans and Neanderthals.
The Sima de los Huesos is not the oldest record of hominids found on the site but has yielded the largest number of hominid fossils in Europe, more than 3000 fragments from at least 27 individuals.
These bones in particular have provided an abundance of evidence for studying diseases and diet.
It would appear that most of the interesting fossils have been whisked off to Madrid to be studied at the university or displayed in museums there. But we did see a large building site in Burgos, called ‘The site for the museum of human evolution’. So it does look as if some of the most interesting fossils may come to rest nearer their original place of discovery.
Eileen A Lawley