former southwest bank of the Euphrates, now under Lake Assad, Syria
Tell Abu Hureyra
A boundary layer about 12,800 years ago (meltglass from a fire, or from a cosmic event)
Before the dam, Abu Hureyra was a mound on the Euphrates. Diggers in 1972 and 1973 took the floors up, and then the lake covered the tell. In the soil is glass that melted. One paper says a hut fire can do that. Another says the glass needed a heat no house fire reaches, at the start of the Younger Dryas cold.
Why this is extraordinary
In 1972 and 1973, before the Tabqa dam made Lake Assad, a team cut into Abu Hureyra, a mound on the southwest bank of the Euphrates. The bedrock is chalky Eocene limestone with thin chert and marl, covered by river sand. The lake then took the tell. What can still be argued is what came out of the floors.
The village is a long settled sequence, with grinding stones now in the Ashmolean that the museum labels Neolithic and does not tie to a layer. The dispute this room is for is the glass in the sediment. A 2020 paper puts a boundary layer at 12,825 ± 55 calibrated years before present, range 12,935 to 12,705, and says that layer is rich in meltglass, nanodiamonds, microspherules and charcoal. The glass is 1.6 percent by weight of the bulk sediment there. About 40 percent of it has plant imprints, which laboratory work formed at a minimum of about 1200 to 1300 degrees Celsius. Melted quartz, chromferide and magnetite are read as proof the melt passed 1720 degrees and, in places, 2200. The paper says a thatched house reaches about 1100 to 1200, lightning would leave a magnetic signature the glass does not have, and the very low water, 0.02 to 0.05 percent, looks like tektite glass rather than a volcano or a potting fire. Iridium, platinum, nickel and cobalt are high, read as a small meteoritic mix. The proxies sit in three trenches as much as 175 metres apart.
A 2015 paper had already looked at scoria droplets 1 to 10 millimetres wide from Abu Hureyra and from Qaramel, Jerf el Ahmar, Dja’de and Mureybet. They come from more than one age, they sit with buildings destroyed by fire, and they were not reported from natural ground. That study concludes the local earth melts in ordinary fires, and that a cosmic heat above 2200 degrees is not required. The two papers even share the number 1200 to 1300 degrees and split on its meaning. One calls it the hottest the fire got. The other heated sediment to about 1700 degrees, saw it stay liquid until 1200, and calls 1200 the freezing point, not the peak.
No sky reading, no solstice line and no star sight, is part of either paper. The event in the cosmic reading is a thing that happened to the ground, not a monument aimed at the sky.
What this changes: if the hot minerals and the metals belong only to that one modelled layer, Abu Hureyra is a settlement caught by a cosmic event at the opening of the Younger Dryas, and the hut fires are a different glass. If the droplets are what burning earth does in several centuries, the village is a place that burned more than once, and the boundary date is the date of a floor, not of an impact.
Why it matters
If the glass is from burning buildings, it belongs with other scorched settlements in northern Syria, and it does not mark a single year. If it formed above 1700 degrees, and only in one layer dated to about 12,800 years ago, this village is a place where a cosmic event met a living floor.
The tell stood on the southwest bank of the floodplain, on chalky limestone with chert and marl, under sandy river alluvium. The samples come from trenches D, E and G, up to 175 metres apart. The site is now under Lake Assad. There is no walk to the floors.
Photo tour
2 photographs, unedited. On a phone, swipe the row. Choose one to look closely.
- The tell is under Lake Assad. No openly licensed photograph of the mound before the flood is in this room. The glass figure and the grinding stones are the objects.
What is still unexplained
These sit beside the consensus account, with the same visual weight. None of them is marked solved.
Location and dating
- Location
- The former village on the southwest bank of the Euphrates, now under Lake Assad. The coordinate, 35.867 north and 38.4 east, is the tell as mapped before the flood.
- Period label
- Current consensus — open to revision The boundary layer is modelled at 12,825 ± 55 calibrated years before present, with a range of 12,935 to 12,705. That is about 10,985 to 10,755 BCE. The village’s other floors are older and younger than that layer. The glass argument is about this layer, not about every century of the mound.
- How this dating was done
- Radiocarbon, brought together in a Bayesian model of the boundary layer in the 2020 paper. The temperature is mineralogy and laboratory heating, not a clock. The 2015 paper dates its droplets by the phases of the buildings they were found in.
- What could change it
- A sample series, from a section that still exists in a store, that shows the high-temperature grains only in the one modelled layer, and not in the burnt houses above and below it. Or the reverse.
What is actually there
- Excavated in 1972 and 1973, then flooded by Lake Assad.
- Meltglass reported as 1.6 percent by weight of bulk sediment in the boundary layer.
- About 40 percent of the glass carries plant imprints.
- Minerals read at a minimum of 1720 degrees Celsius, and some above 2200.
- The same class of droplet is reported from other phases and from other Syrian sites.
- Trenches with the proxies are up to 175 metres apart.
Open questions
| Question | Status |
|---|---|
| Did the glass freeze at hut-fire heat, or did it pass through a much hotter spike first? | Open. The solidus and the mineral grains are both published. They are not the same measurement. |
| Is the glass only in the layer dated to about 12,800 years ago? | Open. The 2015 paper reports droplets in more than one phase at this tell and at other tells. |
The current narrative
Where publication stands today. It is the best-supported reading, and it is open to revision. It is not a verdict.
The current narrative — open to revision
Melt from burning buildings
The droplets are building earth melted in house fires. They occur in more than one period, at more than one site, and they do not require a heat beyond what a fire in a thatched, earth-walled building can reach.
What supports this
- The 2015 study finds the droplets with burnt buildings, and not in natural deposits, at Abu Hureyra and at Qaramel, Jerf el Ahmar, Dja’de and Mureybet.
- At Abu Hureyra they are not limited to a single phase.
- Heating experiments in that study produced comparable melt from the local earth at modest temperatures.
What pushes back
- The 2020 paper reports quartz, chromferide and magnetite that melt far above 1200 degrees, and a water content it compares to tektites.
- Platinum, iridium, nickel and cobalt peak in the boundary layer, which a cooking fire does not add.
- Plant imprints and a modelled age shared with other boundary layers are the pattern the cosmic reading was built to explain.
What would settle it
It is the centre because glass in burnt houses of several ages is the simpler expectation, and the extreme temperatures are argued from grains the other study says it did not see in the interiors. It moves if those grains are shown only in the one dated layer, in more than one store of samples.
Emerging narratives
Other published readings. Each may be right. None is adopted here unless the evidence carries it.
An emerging narrative
A cosmic event at the Younger Dryas boundary
About 12,800 years ago a cosmic event melted sediment at Abu Hureyra at temperatures from 1720 degrees to above 2200, left glass, nanodiamonds, microspherules and charcoal, and mixed in a small amount of meteoritic metal. Hut fires, lightning and volcanoes do not cover that list.
What supports this
- The modelled age, 12,825 ± 55 calibrated years before present, and the same proxies in three trenches up to 175 metres apart.
- High-temperature minerals, low water, low magnetism, and elevated iridium, platinum, nickel and cobalt, as reported in 2020.
- About 40 percent of the glass carries plant imprints, so the melt met vegetation.
What pushes back
- Scoria of this kind is published from other centuries at the same tell and from other villages. A marker that is not unique to the boundary is a weak marker of one impact.
- The 2015 heating work reads the 1200-degree threshold as a ceiling for this melt, not as a freezing point after a hotter spike.
- The tell is drowned. A new section cannot be cut in the field. The argument lives in stored samples.
What would settle it
It stays because the mineral list and the metal peaks are a published case, and because the boundary age is a real model. It is not the centre while the same droplets are reported from fires of other dates.
Should the current view be reevaluated?
Open to revision
Two laboratory readings of one glass do not agree on the highest temperature, and they do not agree on whether the glass picks out one year. Open keeps both until the grains are mapped through the phases.
What drives this
- Meltglass at 1.6 percent of the boundary sediment, with a modelled age near 12,800 years ago.
- Minerals read above 1720 degrees, and a hut-fire study that stops near 1200.
- Droplets in more than one phase, and a site that can no longer be opened.
This is the museum’s own weighing of the evidence. It is not a visitor vote, and it is separate from the slider.
Weigh it yourself
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Visitor lean so far — not evidence. On this browser only; a shared tally is not collected.
If the contested reading is right
What would follow if a reading that is not the consensus turned out to be true, and what could settle it. This explains the stakes. It does not adopt the reading.
The boundary glass is from a cosmic event
Abu Hureyra would be a settlement that was melted at the start of the Younger Dryas cold, not only a village that burned in the ordinary way. Other boundary layers with the same proxies would have a Near Eastern floor to set beside them. The drowned tell could not be re-dug. The test would be in the archives.
Why it is still worth a test
A phase-by-phase count of the high-temperature grains in the stored sections, published beside the 2015 droplet list.
Sources
- Evidence of cosmic impact at Abu Hureyra at the Younger Dryas onset Scientific Reports, 2020
- Anthropogenic origin of siliceous scoria droplets from northern Syria Journal of Archaeological Science, 2015
- Open copy of the scoria-droplet study Author-hosted copy of the 2015 paper
Image credits
- Meltglass from Abu Hureyra, as published with the 2020 study. Colour photographs sit above electron images. Labels mark glass, chromite, monazite and inclusions. The scale bars read 1 millimetre and 2 millimetres. Shown as printed. . Andrew M. T. Moore and co-authors, CC BY-SA 4.0. Shown unedited.
- Grinding stones from Abu Hureyra in the Ashmolean Museum, labelled there as Neolithic. The upper stone is pitted and held clear of the slab. The museum text does not give a layer. . Zunkir, CC BY-SA 4.0. Shown unedited.