The fragments in question, often described in the literature as “debitage,” are the crumbs of sarsen — a hard, silicified sandstone — left behind or displaced during the monument’s construction and later disturbance. While the towering trilithons have attracted centuries of attention, these palm-sized chips have long been regarded as geoarchaeological afterthoughts. That changed when previous researchers applied geochemical provenancing to the fragments, measuring their elemental compositions and comparing them with known sarsen sources across southern Britain. That earlier work concluded that most of the stones, including the massive sarsen megaliths themselves, could be traced to the Marlborough Downs, roughly 25 kilometers north of Stonehenge, while some fragments pointed to more distant or exotic origins.

Michelaki and her colleagues — including David Barham, Michael P. Gorton, William C. Mahaney, Susanne Aufreiter, and Ronald G. V. Hancock — did not collect new samples. Instead, they took the previously published datasets and subjected them to a different kind of analysis. The crux of their critique concerns normalization, a widely used technique in geochemistry in which the concentration of each element is divided by the concentration of a reference element — in this case zirconium, or Zr. Normalization is intended to strip away noise caused by dilution effects, such as varying amounts of quartz in a rock, allowing researchers to compare the underlying chemistry of samples on a level playing field.

The technique has deep roots. Archaeometric studies of pottery, sediments, and metals have long relied on normalizing elements — aluminum for estuarine sediments, scandium for ceramic pastes, zirconium for silica-rich rocks — to counteract the enormous spreads in raw elemental concentrations that obscure meaningful comparisons. In the Stonehenge work, Zr normalization formed the backbone of the provenance assignments: when fragment ratios matched the ratios of a candidate source, the fragment was deemed to originate there. On the surface, the logic is sound and elegant.

But the new reanalysis shows that the elegance comes at a cost. When the same data are plotted without normalization, using raw elemental concentrations and a visual, geochemically informed graphical approach that explicitly acknowledges analytical variability, a different picture emerges. Similarities that appeared compelling under Zr-normalized ratios are not always supported across multiple elements. In some cases, normalization generated apparent agreements between fragments and sources that dissolve the moment other elements are considered. In other cases, genuine coarse geochemical groupings visible in the raw data simply vanish when everything is divided by zirconium.

The problem, the authors explain, is mathematical as much as geological. Dividing one element by another collapses two independent pieces of information into a single ratio, and if the normalizing element itself varies substantially across samples — as Zr can in silcretes, where zircon-bearing grains may be unevenly distributed — the ratio can swing wildly for reasons that have nothing to do with shared provenance. Two chemically unrelated rocks can end up with similar ratios, while two chemically related rocks can be driven apart. The result is a classification scheme that may obscure real compositional differences and invent apparent ones.

So what happens to the Stonehenge fragments when the crutches are removed? Using their non-normalized approach, Michelaki’s team found that only some of the fragments can be tentatively associated with previously characterized sarsen sources. Many others remain stubbornly unsourced, or appear to represent geochemistries that have not yet been documented anywhere in Britain’s known sarsen outcrops. The authors are careful with their language — they use “grouping” rather than “group” to stress that these chemical clusters are far more dispersed than the tight compositional families typical of a single geological source. But the implication is striking: the geochemical variability of the silcrete materials at Stonehenge may be considerably greater than the earlier analyses suggested.

Far from undermining the broader narrative of Stonehenge’s construction, this increased variability actually aligns with a growing body of evidence that the monument is a composite of materials drawn from across Britain. The most dramatic example is the Altar Stone, whose recent sourcing to the Orcadian Basin in northern Scotland — hundreds of kilometers from Wiltshire — stunned the archaeological community and demonstrated that long-distance stone transport, whether by human effort or glacial action, was part of the monument’s biography. The bluestones from the Preseli Hills of Wales tell a similar story. Against this backdrop, sarsen fragments with unassigned or unexpected chemistries are less an anomaly than a further hint that the builders drew on a wider and more varied portfolio of stone than once assumed.

The study is also notable for what it declines to do. Rather than offering new definitive provenance assignments, the authors frame their contribution as a methodological intervention: a reflexive evaluation of how analytical choices shape archaeological interpretation. The Stonehenge case becomes a cautionary tale for provenance studies in general. Archaeometry has a long history of these debates, from the Olmec controversy, where competing statistical treatments of neutron activation data produced radically different pictures of ceramic exchange in ancient Mesoamerica, to ongoing discussions about how to define chemical reference groups in pottery. The lesson, repeatedly learned and just as repeatedly forgotten, is that data do not interpret themselves — and that a technique convenient enough to become standard practice deserves periodic scrutiny.

The timing of the intervention is significant. The original provenancing of the sarsens, published in Science Advances in 2020, was widely celebrated as solving one of Stonehenge’s enduring mysteries, and subsequent work on the fragments extended that framework. A parallel debate has been playing out in the pages of the journal Archaeometry over the sourcing of sarsen stone 58, with the present team contributing geochemical analyses of that monolith and engaging in exchanges with other researchers over methodology. The new paper effectively widens the conversation: if normalization can obscure differences and manufacture agreements in the fragment data, then provenance claims built on those ratios — for the fragments and potentially for the megaliths themselves — warrant reexamination under multiple analytical lenses.

None of this means the Marlborough Downs connection is wrong. The 2020 study’s core insight, that the great sarsens share a distinctive chemistry matching a specific outcrop called West Woods, was based on a robust correspondence and remains the most parsimonious explanation for the megaliths. But the new work insists that confidence should be calibrated to the evidence. Some fragment-to-source matches may hold up under non-normalized scrutiny; others may not; and a substantial portion of the material may simply await the characterization of sarsen sources that have not yet been sampled. Britain’s sarsen distribution is patchy and imperfectly mapped, scattered in a belt from Dorset through Wiltshire to Kent and beyond, and glacial processes during the last British-Irish Ice Sheet’s advance and retreat have redistributed stone across the landscape in ways that complicate simple local-versus-exotic dichotomies.

For the wider field, the stakes extend well beyond one monument. Provenance studies underpin claims about trade networks, migration, territoriality, and social organization from the Neolithic to the historic period, and they increasingly feature in heritage policy debates about stone conservation and sourcing. When a single statistical transformation can tip the balance between “local stone” and “stone from nowhere we know,” the responsibility on practitioners is considerable. The authors’ recommendation is not to abandon normalization outright — it remains a legitimate and often useful tool — but to apply it reflexively, testing whether conclusions survive when the data are viewed in their raw form, element by element.

In the end, the study is a portrait of science working as it should. Two teams, using the same numbers, reach different conclusions, and the disagreement itself becomes a discovery: the stone fragments of Stonehenge are more chemically diverse, and their journeys more complicated, than anyone had asserted. For a monument that has resisted definitive explanation for a thousand years of inquiry, that may be fitting. The researchers, who note their work was enabled by “curiosity, stubbornness, and retirement,” have reminded the field that at Stonehenge, as in geochemistry, certainty should always be earned — and re-earned — rather than assumed.

Gesher Benot Ya‘aqov, a key archaeological site located along the paleo-shores of ancient Lake Hula, offers a rich record of Acheulian hominin activity from the early Middle Pleistocene. Excavations at GBY have unearthed a diverse array of artifacts, ranging from flint and limestone tools to extensive evidence of early fire use, as well as dietary traces including animal processing and fish consumption. Among these artifacts, basalt holds particular significance owing to its role in producing large cutting implements such as handaxes and cleavers—tools requiring intricate craftsmanship and raw material knowledge.

The crux of this latest research centers on detailing the procurement strategies employed by early hominins for basalt raw material, delving into the geological sources and their accessibility in ancient landscapes that have since transformed due to tectonic and sedimentary processes. Utilizing geochemical analyses, including examination of major and trace elements as well as rare earth elements, the study compares the compositional fingerprints of basalt artifacts recovered from multiple archaeological layers with basalt flows exposed in the surrounding region. A pivotal part of the methodology involved analyzing basalt samples extracted from the Eshel Ya‘aqov borehole, offering unprecedented access to subsurface basalt units currently buried beneath the modern site.

The results reveal a nuanced picture: many of the basalt tools correlate closely with local geological sources within roughly one kilometer of GBY, indicating the hominins exploited nearby raw materials effectively. However, a remarkable facet of the findings is the match of certain lithic materials with basalt flows that are no longer visible on the surface, having been buried or eroded by geological forces over hundreds of thousands of years. This discovery of “lost” basalt sources underscores the importance of integrating borehole stratigraphy and geochemistry to reconstruct vanished parts of the prehistoric landscape, highlighting the dynamic tectonic activity along the Dead Sea Transform fault system.

A particularly striking outcome of the research is the clear differentiation in raw material selection based on specific tool types. While giant cores—a primary stage in tool production—were predominantly fashioned from locally accessible basalt, cleavers frequently trace back to basalt sources not identified among currently exposed basalt outcrops. This distinction suggests a deliberate selection process whereby hominins sought out basalt flows that possessed unique properties deemed ideal for crafting certain specialized tools, pointing toward sophisticated knowledge of the material’s physical qualities such as slab size, textural uniformity, and fracture mechanics.

This degree of selectivity and material discrimination also implies advanced cognitive planning and extended territorial knowledge. The fact that such procurement strategies persisted continuously across multiple stratigraphic layers at GBY provides compelling evidence for the transmission of technological traditions and environmental expertise over extended periods. This continuity manifests a kind of cultural inheritance, with hominins repeatedly returning to or recalling specific basalt sources to fulfill particular tool-making requirements, thereby demonstrating behavioral complexity previously underestimated for this era.

Moreover, the study strengthens the interpretation that Acheulian hominins possessed a sophisticated “toolkit economy”: a structured approach to raw material exploitation that involved anticipating the lifecycle of artifacts from source selection through blank production to finished tool modification. The linkage of geological data and archaeological evidence exemplifies how early technology was embedded within a broader environmental and geospatial framework, requiring deep familiarity with the landscape—a landscape that, crucially, was subject to constant reshaping through seismic and erosional forces.

The novel integration of geochemistry and archaeological context at GBY offers a valuable methodological blueprint for understanding early human adaptation in tectonically active regions. It challenges prior assumptions that early hominins indiscriminately utilized whatever stone was locally available and instead positions them as strategic agents exercising foresight and discrimination in raw material procurement. This emerging perspective reverberates far beyond GBY, inviting reevaluation of early hominin behaviors associated with toolmaking across various geographic and temporal contexts.

Importantly, the findings spotlight the role of buried prehistoric landscapes, urging archaeologists to consider subsurface geology alongside surface surveys to gain a complete picture of raw material availability and exploitation. The Eshel Ya‘aqov borehole data exemplifies how geochemical sourcing anchored in deep stratigraphy can illuminate past environmental conditions hidden beneath contemporary exposure, illustrating the benefits of multidisciplinary approaches combining geology, chemistry, and archaeology.

In summary, this pioneering research portrays the Acheulian hominins at Gesher Benot Ya‘aqov as innovative and knowledgeable toolmakers who mastered the procurement and transformation of basalt resources within a complex and evolving landscape. Their ability to identify “the right rock for the right tool at the right time” reflects cognitive capabilities and cultural traditions that substantially enhance our understanding of early human technological evolution and environmental interaction during the Middle Pleistocene.

By spotlighting the strategic behaviors of hominins 780,000 years ago, this study enriches the narrative of human prehistory, revealing that our ancestors’ technological sophistication and environmental savvy extend far deeper into time than previously recognized. It emphasizes that technological traditions were not static but repeatedly refined through intergenerational knowledge transfer molded by the challenges and opportunities presented by their dynamic environment.

Subject of Research: Not applicable

Article Title: Geochemical basalt investigation reveals procurement strategy at the Acheulian site of Gesher Benot Ya‘aqov, Dead Sea Transform, Israel

News Publication Date: 14-May-2026

Web References: http://dx.doi.org/10.1038/s41598-026-51905-0

Image Credits: T. Golan

Keywords: Archaeology, Geochemistry, Hominins