Long before anyone built a deliberate kiln, wildfires burning across the hills of the ancient southern Levant may have already shown people what fire does to clay. A new study argues that a period of intense natural fires and landscape upheaval left the region blanketed in fire-hardened clay right around the time the first pottery appears in the archaeological record, raising the possibility that potters were imitating a process nature had already performed for them.
The research, led by geomorphologist Amos Frumkin of the Institute of Earth Sciences at the Hebrew University of Jerusalem, focuses on the Jordan Valley village of Sha’ar Hagolan and the broader Yarmukian culture that produced some of the region’s earliest and most technically accomplished ceramics.
The “natural kiln hypothesis”
Frumkin calls his idea the natural kiln hypothesis, and the mechanism behind it is straightforward. Deep inside an intense wildfire, exposed clay can reach temperatures of roughly 500 to 700 degrees Celsius, the same range a kiln needs to permanently harden clay into ceramic. If wildfires swept the hills above the Jordan Valley with enough frequency and intensity, and the resulting baked clay ended up in places where people were already living, then whoever eventually built the first deliberate kiln may not have discovered the underlying principle so much as recognized something they had already seen happen naturally, according to a report on the study, published in the journal Geomorphology.
That reframes the emergence of pottery as something other than a slow accumulation of trial and error around hearths and storage pits. It suggests a specific environmental event may have handed early potters a working demonstration of the transformation they would later reproduce on purpose.
Reading fire history in lake mud and cave stone
To reconstruct how much of the region actually burned, Frumkin turned to two very different kinds of evidence. Long sediment cores drilled through the beds of the Dead Sea and Lake Hula preserve microscopic charcoal fragments layer by layer, giving researchers a direct record of burning intensity over thousands of years. In the Soreq and Har Nof caves near Jerusalem, slow-growing mineral formations called speleothems trap carbon and strontium that shift chemically when the hillsides above them lose their plant cover and topsoil erodes away.
Lining those two records up, Frumkin found that both indicators moved together across two separate intervals of environmental instability separated by more than 100,000 years. In each case, charcoal counts spiked, the chemical signatures of vegetation loss swung sharply, and the surrounding hillsides lost their soil. The most intense pulse in the more recent interval shows up in the Lake Hula core at approximately 9,500 years ago, when charcoal counts roughly tripled compared to the period before it.
A regional fire, not a farming accident
One obvious alternative explanation is that Neolithic farmers themselves set these fires, whether to clear land or manage vegetation, which would make the pattern a side effect of early agriculture rather than a genuinely natural disaster. Frumkin argues against that reading by pointing to a charcoal spike dated independently to about 9,600 years ago in a lake core from the Ghab Valley in northwestern Syria, hundreds of kilometers north of the Jordan Valley.
Because that distant site shows a fire spike at essentially the same time, Frumkin treats the burning as a broader regional and climatic event rather than something driven by farming activity in any single valley. That distinction matters for the hypothesis, since a widespread natural fire is far more likely to have deposited baked clay across many inhabited sites at once than a series of small, deliberately set local burns.
Where the clay ended up
The fires and the erosion that followed them left thick deposits of redeposited clay in the valleys below, recorded geologically as the Fazael Formation in the Jordan Valley and the Ze’elim Formation around the Dead Sea, in places piling up tens of meters deep. Upslope, the effect looked more like abandonment: a large Pre-Pottery Neolithic settlement at Motza, in the Judean highlands, appears to have been deserted right around the peak of the fires, its local soils exhausted by erosion.
Downslope, the same event became a resource rather than a loss. Sha’ar Hagolan, along with the well-known Neolithic villages of Jericho, Netiv Hagdud and Gilgal, all sit on freshly redeposited soil, in exactly the low-lying spots where eroded hillside material would have accumulated. A 1992 petrographic study of pottery from Munhata, another Yarmukian-culture site in the Jordan Valley, had already traced the raw material in that pottery to terra rossa, the reddish soil eroding off the slopes above the valley floor, with no evidence that potters sought out a special or distant clay source.
A hypothesis that still needs testing
Frumkin is careful to frame the natural kiln hypothesis as a proposed addition to existing explanations for pottery’s origins rather than a replacement for them. Longstanding accounts that credit gradually accumulated experience, the appeal of prestige vessels for feasting, and growing populations needing better ways to store and cook food all remain plausible parts of the picture. What the new study adds is a specific, testable mechanism for how the underlying idea of firing clay might have first become visible to people who had not yet thought to do it deliberately.
The timing lines up: a landscape saturated with naturally fire-hardened clay appears in the geological record before pottery shows up in the archaeological layers at Sha’ar Hagolan, rather than after. Frumkin notes that experimental work reproducing wildfire conditions in the lab could help confirm whether fires of the intensity documented in the charcoal and speleothem records were actually capable of hardening clay to the same degree as an intentional kiln, a step that would move the hypothesis from a plausible correlation toward a demonstrated mechanism.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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