One of the key debates regarding human evolution and migration revolves around when and how the earliest hominids made their way to Europe from Africa. Recent geological dating at the Orce sites in Granada, Spain, suggests that the human remains discovered there are approximately 1.3 million years old, marking them as the oldest in Europe. This gives support to the theory that humans entered Europe from the southern part of the Iberian Peninsula via the Strait of Gibraltar, rather than taking a return route through the Mediterranean via Asia.
One of the key debates regarding human evolution and migration revolves around when and how the earliest hominids made their way to Europe from Africa. Recent geological dating at the Orce sites in Granada, Spain, suggests that the human remains discovered there are approximately 1.3 million years old, marking them as the oldest in Europe. This gives support to the theory that humans entered Europe from the southern part of the Iberian Peninsula via the Strait of Gibraltar, rather than taking a return route through the Mediterranean via Asia. The research, led by LluÃs Gibert, a professor and researcher at the University of Barcelona’s Faculty of Earth Sciences, involved collaboration with experts from the Berkeley Geochronology Centre and Murray State University in the United States.
Investigation of a New Sampling Area
The recent dating efforts focused on analyzing the paleomagnetism of a previously unexamined region within the Orce area, which has escaped significant erosion over time. This method measures relative dating based on magnetic pole reversals caused by Earth’s internal dynamics. Although these changes don’t follow a specific pattern, they can be recorded in minerals, allowing researchers to identify various periods based on differing magnetic events.
The accuracy of the new findings stems from the lengthy sedimentary sequence present in Orce, exceeding eighty meters in depth. “The distinctiveness of these sites lies in their stratified layers within this extended sedimentary record. Typically, such sites are found in caves or display limited stratigraphic sequences, which do not permit the development of extensive paleomagnetic sequences featuring various magnetic reversals,” explains LluÃs Gibert.
The research team identified a magnetic polarity timeline containing “five magnetic events that enable them to date the three Orce sites with evidence of human occupation between the Olduvai and Jaramillo subchron, dating from 1.77 to 1.07 million years ago,” according to the researcher. They then utilized a statistical age model to fine-tune the chronology of the distinct stratigraphic layers, achieving a margin of error of only 70,000 years. Consequently, the oldest site with human presence in Europe is determined to be Venta Micena, estimated at 1.32 million years old, followed by Barranco León at 1.28 million years old, and finally Fuente Nueva 3 at 1.23 million years old. “As a result, another significant site in the peninsula, Sima del Elefante in Atapuerca, is positioned as far younger, between 0.2 and 0.4 million years more recent than Orce,” adds the researcher.
Faunal Evidence Supporting the Site’s Antiquity
To complement the dating process, the study also examined the animal remains found at the various Orce sites since these vary by time period. This analysis was then compared with findings from other Early Pleistocene locations throughout Europe.
A comprehensive review of the micromammals and large mammals from all Orce sites was conducted by expert Robert Martin, utilizing palaeontological collections housed at the Museum of the Catalan Institute of Palaeontology Miguel Crusafont (IPS) in Sabadell. “The results show that the small and large fauna from Orce are more primitive compared to that of Sima del Elefante, where data indicates the rodent Allophaiomys lavocati is more evolved than the Allophaiomys discovered at the Orce sites,” Gibert clarifies.
Another significant marker of the Orce sites’ age is the absence of pig ancestors. “These species are recognized as Asian immigrants and have not been recorded at any European sites between 1 and 1.5 million years ago, while they have been noted at Sima del Elefante, suggesting that the fauna at Orce is older,” the researcher highlights.
Evidence Suggesting Passage Through Gibraltar
This updated dating method is part of a broader collection of evidence supporting the theory that the colonization of Europe occurred via the Strait of Gibraltar, rather than the alternative option of returning to the Mediterranean through Asia. This evidence includes “the discovery of a lithic industry resembling those found in northern Africa, as well as the presence of African fauna remains in the southern peninsula, such as Hippopotamus found at Orce, and Theropithecus oswaldi, an African primate akin to baboons, which was found at the Victoria cave near Cartagena (Murcia), which does not exist elsewhere in Europe,” Gibert explains.
“We also support the theory — adds the researcher — that they migrated from Gibraltar, as no older evidence has surfaced at any other locations along the other potential routes.”
The data from Orce’s long sedimentary sequence are critical in these findings.
Similarities with Hominids from Flores Island
These findings lead researchers to propose a “diachronism” regarding human occupation: the oldest known occupation in Asia is approximately 1.8 million years old, while the earliest occupation in Europe appears to be around 1.3 million years ago. This suggests that African hominids reached southwestern Europe over 0.5 million years after their initial departure from Africa around 2 million years ago. “These discrepancies in human migration can be attributed to Europe being isolated from Asia and Africa by challenging biogeographical barriers, both to the east (Bosphorus Strait, Dardanelles, Sea of Marmara) and to the west (Strait of Gibraltar). Humanity likely reached Europe once they had developed the technology necessary to overcome marine barriers, similar to the events on Flores Island (Indonesia) nearly a million years ago,” Gibert states. The researcher further notes that while the current Gibraltar route spans about fourteen kilometers of sea, “historical tectonic activity and sea level fluctuations could have shortened this distance at various times, making migration easier.”
“As referenced in the paper — he adds — we’ve identified previous migrations of African fauna through Gibraltar dating back to 6.2 and 5.5 million years ago when the Strait was relatively narrow.”
Human Remains Found in Orce
Since excavations commenced in 1982 under the guidance of paleoanthropologist Josep Gibert, a total of five human remains have been recovered from the Orce sites. Initially, two fragments of a humerus, believed to have been scavenged by hyenas, were unearthed at Venta Micena. Additionally, parts of a cranial fragment comprising two parietals and an occipital were associated with abundant Early Pleistocene fauna. Despite sparking significant debate regarding the human origin of these remains, separate independent palaeoproteomic analyses conducted by the universities of Granada and San Francisco confirmed the presence of human proteins in the samples.
Furthermore, the later discovery of two human molars and thousands of Olduvai-style lithic tools at the nearby Barranco León and Fuente Nueva 3 sites — among the earliest known human tool industries — as well as cut marks on bones, “served to further substantiate the evidence of hominid presence during the Early Pleistocene in Orce,” concludes LluÃs Gibert.
