New excavations in Equatorial Guinea document human occupations between 40,000 and 20,000 years ago in the fluvial environments of the Ntem River
The thirteenth archaeological campaign in the country has identified several occupation episodes associated with an ancient river island and recovered nearly 700 archaeological finds, including more than 500 stone tools
An international research team led by Antonio Rosas, researcher at the National Museum of Natural Sciences of the Spanish National Research Council (MNCN-CSIC), has documented new evidence of human groups associated with the cultural traditions of the Middle Stone Age (MSA) in northwestern Equatorial Guinea. The results indicate that these populations occupied the fluvial environments near the mouth of the Ntem River, close to the present-day border with Cameroon, between approximately 40,000 and 20,000 years ago.
The work forms part of the thirteenth archaeological and palaeontological research campaign carried out in Equatorial Guinea by a multidisciplinary team of specialists from the National Museum of Natural Sciences (MNCN-CSIC), IPHES-CERCA, the University of León, the National University of Equatorial Guinea (UNGE), and the National Institute for Forestry Development and Protected Areas Management (INDEFOR-AP). The campaign has focused mainly on Campo 11, one of the archaeological sites identified during previous survey seasons and already reported in international scientific journals.
Reconstructing an ancient fluvial landscape
A major objective of the campaign has been to reconstruct the geological and sedimentary setting in which these human occupations took place. To achieve this, the team recorded twelve stratigraphic sections and collected numerous sediment samples from different areas of the fluvial system.
This work has made it possible to define the position of ancient river channels and identify the sedimentary deposits that formed the river island occupied by human groups. Combining archaeological excavation with geomorphological research provides insight not only into when the site was occupied, but also into the characteristics of the landscape and the resources available at different times.
“The results reveal a highly dynamic environment shaped by changes in the river course, channel formation and the gradual accumulation of sediments,” explains Antonio Rosas, researcher at MNCN-CSIC and director of the project. “Within this context, the elevated areas of the river islands would have provided favourable locations for a range of human activities.”
Nearly 700 archaeological finds recovered
During this campaign, the excavated area at Campo 11 was expanded to approximately 20 square metres. The excavation yielded nearly 700 archaeological finds, including more than 500 stone tools and knapping remains related to stone tool production. A significant assemblage of charcoal was also recovered, and its analysis will help determine its origin and assess its possible association with human activities at the site.
The excavation exposed an almost four-metre-thick sedimentary sequence preserving several archaeological horizons corresponding to successive occupation episodes. The study of these levels will provide valuable information on the variability of the technological strategies employed by these populations and how they evolved over time.
The excellent preservation of the archaeological materials and their spatial distribution has made it possible to begin identifying specific activity areas, particularly those related to stone tool manufacture. “For the first time since research began in the country, we have excavated archaeological contexts with an exceptional degree of preservation. The spatial distribution of the finds allows us to identify activity areas associated with different stages of the stone tool production process,” explains Juan Ignacio Morales, researcher at IPHES-CERCA and director of the archaeological excavations at Campo 11.
The spatial analysis of these concentrations will make it possible to reconstruct some of the technical behaviours carried out by the people who occupied the site, from the selection of raw materials to the manufacture, use and discard of stone tools.
The Middle Stone Age in the Central African rainforest
The knapping strategies identified and the characteristics of the recovered artefacts link the Campo 11 assemblages to the technological traditions of the Middle Stone Age (MSA).
The Middle Stone Age represents a key period for understanding the origin, evolution and dispersal of Homo sapiens across Africa. However, most of the available evidence comes from open, arid or semi-arid regions of eastern and southern Africa. By contrast, our knowledge of the populations that inhabited the tropical rainforests of Central Africa remains much more limited. Research in Equatorial Guinea therefore provides an exceptional opportunity to understand how human groups adapted to one of the continent’s most complex ecosystems, characterised by dense vegetation, high humidity, intense fluvial activity and environmental conditions that are particularly unfavourable for the preservation of archaeological sites.
“The knapping strategies and the typology of the recovered tools clearly associate these assemblages with the cultural traditions of the Middle Stone Age. The emergence and development of these technologies within the tropical rainforest of Central Africa is of great importance for understanding the expansion of Homo sapiens and its remarkable capacity to adapt to highly demanding ecological settings,” says Antonio Rosas.
These new findings demonstrate that tropical rainforest environments were not marginal or uninhabited landscapes, but territories that were repeatedly occupied by human groups capable of adapting their technological and subsistence strategies to highly specific ecological conditions.
New work at Temelón 50
In addition to the excavations at Campo 11, the team carried out stratigraphic documentation, sedimentological description and sampling at Temelón 50, another of the main archaeological sites identified during previous survey campaigns. This work will make it possible to compare the sequences from both sites and assess whether they represent contemporary occupations, successive settlement episodes or different patterns of use of the fluvial landscape. Integrating the archaeological, geological, chronological and palaeoenvironmental data obtained from Campo 11 and Temelón 50 will contribute to building a regional sequence for human occupation in present-day Equatorial Guinea during the Late Pleistocene.
An international and multidisciplinary project
The research brings together specialists in human evolution, archaeology, geology, geomorphology, lithic technology, geochronology and palaeoenvironmental reconstruction. Collaboration between Spanish and Equatorial Guinean institutions is essential not only for carrying out the fieldwork, but also for strengthening research, heritage protection and the preservation and promotion of Equatorial Guinea’s archaeological record.
Funding
The research has been funded by the Palarq Foundation and the Spanish State Research Agency through project PID2021-122356NB-I00 and the Ramón y Cajal fellowship RYC2024-048167.
