Замби улсаас 476 мянган жилийн настай, зориудаар угсарч хийсэн модон байгууламжийн үлдэгдэл олджээ

Long before Homo sapiens existed, someone was shaping trees.

At Kalambo Falls in northern Zambia, a site perched above a river gorge that feeds one of Africa’s highest uninterrupted waterfalls, archaeologists in 2019 pulled two interlocking logs from waterlogged sediments. The logs had been deliberately cut and fitted together using a notch carved transversely into one of them, forming a joint. Luminescence dating of the surrounding sediments placed them at least 476,000 years old. That is roughly 240,000 years before our own species appeared.

The findings, published in Nature, were led by L. Barham of the University of Liverpool, who has spent years excavating the Kalambo basin and tracing the deep roots of human technological behavior. The paper describes not just the interlocked logs but four additional modified wood tools recovered from the same site across three time clusters: a wedge, a digging stick, a cut log, and a notched branch, spanning from roughly 390,000 to 324,000 years ago.

A Construction With No Known Parallel

The instinct when reading about ancient wooden objects is to picture crude sticks. The Kalambo logs are something else.

The upper log, a species called Combretum zeyheri, runs 141 centimeters long. Cut into it is a U-shaped notch, 13 centimeters long by 11 wide, shaped by scraping and adzing with stone tools. A second, larger trunk passes through that notch beneath it. Both logs show evidence of intentional shaping on their surfaces: scraping marks, chopping facets, parallel striations cut transverse to the grain.

The researchers found no comparable construction anywhere in the African or Eurasian Palaeolithic record. This is not the oldest shaped piece of wood ever found, but it is the oldest known case of two pieces of wood being deliberately joined into a structure.

What that structure was for is not settled. The researchers suggest it may have served as a raised platform, a walkway, or a foundation for a dwelling, pointing to the site’s environment: a periodically flooded riverine floodplain where an elevated surface would have been practically useful. The region was forested for much of the relevant period, between roughly 470,000 and 274,000 years ago, giving hominins consistent access to large timber.

The Problem of Preservation

Wood almost never survives this long. That is the blunter version of what the paper’s abstract politely describes as requiring “exceptional conditions.”

At Kalambo Falls, a permanently elevated water table did what dry air cannot: it kept oxygen away from the buried material, slowing decomposition to the point where the cellular structure of wood from nearly half a million years ago is still identifiable under a scanning electron microscope.

Researchers confirmed the species of each log using SEM analysis at the British Museum and verified that the wood was not intrusive, meaning it had not washed in from a later period. Radiocarbon dating came back infinite on all samples, consistent with material far older than 50,000 years. The actual age was established through luminescence dating of sand grains in the sediment layers above and below the finds.

That dating method measures how long mineral grains have been buried by tracking the radiation they have absorbed over time. Sixteen samples were collected across the excavation site. The results placed the oldest logs in a cluster averaging 476,000 years, with the uncertainty range suggesting they could be older still if a correction for fading in the feldspar signal is applied.

What These Hominins Could Do

The species responsible for the construction is not known with certainty. At 476,000 years ago in southern Africa, the likely candidates are archaic forms of Homo, possibly ancestors of Neanderthals and modern humans both, predating the split between those lineages. The Acheulean stone tools found with the wood, including handaxes and cleavers, are consistent with what is known from that period.

What the Kalambo finds force is a harder look at what these toolmakers were cognitively capable of. The researchers argue that joining two components to form a larger structure is not just a carpentry skill. It reflects what they call technical cognition: the ability to plan a construction, select appropriate materials, and work toward a functional outcome that did not previously exist.

That same underlying logic, combining separate parts into something new, is the concept behind hafting, which appears in the archaeological record hundreds of thousands of years later.

The digging stick and the wedge recovered from later layers at the same site add texture. They suggest that woodworking at Kalambo was not a one-off event but a sustained practice, varied in its forms, carried out by hominins who returned to this river margin across generations.

Africa’s Wooden Record, Rewritten

Until now, the oldest clearly modified wood objects from Africa dated to around 390,000 years ago. A stick with a possible chop mark from Amanzi Springs in South Africa and fragments from earlier Kalambo excavations in the 1950s had hinted at earlier woodworking, but the evidence was ambiguous. The 2019 excavation resolved that ambiguity with two interlocked logs that could not have been shaped and fitted by water or accident.

The broader implication is quieter but harder to dismiss. Most of what archaeologists know about early hominin behavior comes from stone. Stone survives. Wood, bone, hide, fiber: almost none of it does, which means the technological record of our ancestors is systematically biased toward whatever happened to be made of rock.

Kalambo Falls, with its unusual hydrology, offers a glimpse of a parallel tradition. How extensive that tradition was, and how far back it goes, the sediment has not finished telling.

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