Deep in the Sierra de Atapuerca mountains of northern Spain, researchers are pointing hyperspectral cameras at ancient sediments and fossils—capturing details of the past that human eyes have never seen. The Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) and the Instituto Tecnológico de Castilla y León (ITCL) have partnered to deploy infrared imaging technology at the Gran Dolina Site, one of Europe's most significant archaeopalaeontological locations, revealing the hidden composition of layers that began forming 1 million years ago.
What makes this work matter is both the timeframe and the method. The researchers are focusing on levels TD3 and TD4—the oldest sediments at Gran Dolina—which formed when groundwater receded from the cave and sediments from the mountain slopes began accumulating within it. This transition marked a pivotal moment in the site's geological history: the beginning of animal fossil and stone tool accumulation. Using technology that extends detection capabilities far beyond what the naked eye can perceive, scientists can now document these fragile archaeological records without damage or destruction.
Hyperspectral analysis works by capturing light reflected by different materials across a broad range of wavelengths—hundreds of bands in the visible spectrum and, for the first time at this site, sensors recording the infrared spectrum beyond human vision. "We used a hyperspectral camera operating in the visible and near-infrared range, extending detection capabilities beyond what can be perceived by the human eye," explains CENIEH geologist Alfonso Benito Calvo, who led the initial fieldwork. The camera records reflected light information at every point on an analyzed surface, generating images with extraordinary spatial and spectral detail. Once collected, the data are processed using statistical techniques and analytical algorithms that classify and differentiate materials, creating compositional maps of the site.
The practical applications are profound. Hyperspectral technology can identify differences in material composition—sediments, fossil remains, stone tools—based on their characteristic spectral signatures, much like a fingerprint unique to each material. Julen Rostan, head of the Intelligent Artificial Perception Systems research group at ITCL Centro Tecnológico, notes that this approach makes "it possible to identify differences in the composition of materials present at archaeological sites...based on their characteristic spectral signatures." By moving beyond the visible range, researchers can improve compositional characterization of sediments and enable automatic documentation of the archaeopalaeontological record entirely through non-destructive means.
The fieldwork itself was meticulously designed. Researchers collected data under three different conditions—daylight, nighttime, and controlled artificial lighting—to understand how sediments and fossils respond to varying illumination. This methodical approach ensures the technology's reliability and reproducibility.
What lies ahead is unprecedented insight into the earliest stages of Gran Dolina's formation. The combination of hyperspectral cameras capturing hundreds of visible-spectrum bands alongside infrared sensors could reveal information previously invisible to science. For a site where every layer holds clues to human evolution and adaptation, the ability to read those layers in infrared light opens entirely new chapters in our understanding of the past.