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Scientists at the University of Malaga have shown, in an unprecedented way, how the so-called "elephant graveyard" of the Early Pleistocene archaeological site of Orce—a name given due to the amount of remains of the extinct elephant species Mammuthus meridionalis that it contained—hid a natural trap in quicksand.

The study is in the Journal of Iberian Geology.

The site of Fuente Nueva 3 (FN3), located in the northeastern margin of the Guadix-Baza Depression (Granada), is one of the deposits of Orce that contains some of the earliest evidence of human presence in Western Europe, consisting of lithic assemblages (stones carved by our ancestors) that are dated to 1.4 million years ago.

Likewise, this archaeological site preserves manuports—unmodified stones used as percussion tools to fracture bones and access the marrow and, perhaps, also used as throwing weapons to scare away hyenas—and abundant fossils of large mammals, some of which preserve anthropogenic marks related to skinning, butchering and marrow processing. There are also bones with tooth marks caused by scavenging carnivores.

Two archaeological levels

According to this study, co-led by Full Professor of Paleontology at the UMA Paul Palmqvist and Professor of Stratigraphy and Paleontology at the UMA María Patrocinio Espigares, the fertile layers of this site have two different archaeological levels: lower (LAL) and upper (UAL).

Both levels preserve abundant skeletal remains and lithic tools. However, while the first one shows a high density of manuports, which suggests that hominin activity was more intense at this level, the second one preserves many remains of megaherbivores, particularly, the extinct elephants Mammuthus meridionalis, which points to a greater involvement of the giant hyenas.

The scientists analyzed the statistical differences in the composition of the faunal assemblages preserved in these two levels and the sedimentology, specifically the particle size in the fertile layers of both levels. The latter is a key aspect in the research, as it shows a predominance of silts and clays in layers 2–3 of the lower level, and fine and very fine sands in layer 5 of the upper level.

"These fine sand sediments, deposited close to the paleolake that was in the region, would also contain slightly saline water, a mixture that explains that they could have worked as quicksand, where larger animals were trapped," say the UMA scientists.

Food for scavengers

The researchers point out that the latter level may be interpreted as a natural quicksand trap in which megaherbivores were trapped due to the elevated weight of their limbs, and their half-sunken carcasses attracted the scavengers, both hyenas and humans, which fed on these and left their lithic assemblages and coprolites—fossilized excrement of hyenas—as evidence of their presence.

The new finding discovered by UMA researchers represents a "very important milestone to gain more knowledge about the subsistence strategies of our ancestors, the first Europeans, and their competition with the large carrion hyenas for access to these meat resources, since it is the first time a natural trap with these characteristics has been described in a fossil deposit of special interest to human evolution."

Carrying out more detailed studies differentiating the upper and lower archaeological levels, as well as characterizing other important sites in the Orce region, such as Barranco León, which also contributes evidence of human presence, are the next steps planned by this scientific team of the UMA, in which researchers from the Complutense University of Madrid and Tarragona also participate.