The mystery of a series of prehistoric stone circles containing thousands of olive pits, found just off Israel’s northern coast a decade ago, has been solved. Archaeologists have concluded they were apparently facilities for pickling olives 6,500 years ago – the earliest evidence found so far for the production of this food.
The study, published last week in Nature Scientific Reports, suggests, somewhat counterintuitively, that people only figured out they could eat olives at least 500 years after they learned to squeeze precious oil from the fruit. It also adds to mounting evidence that today’s Israel was the region where prehistoric farmers first cultivated and domesticated the olive tree, which later became a staple crop across the Mediterranean.
The site at Hishuley Carmel, just south of the city of Haifa, was exposed in 2011 after a storm washed off layers of sand that had covered it for millennia, explains Prof. Ehud Galili, a marine archaeologist at the University of Haifa who led the team.
Over the past decades, archaeologists have found 19 prehistoric sites off Israel’s northern Carmel coast, which were inundated and abandoned as glaciers melted after the last Ice Age and sea levels rose worldwide, Galili says. These ancient remains, well preserved by the silt that covered them, have given experts invaluable information on life in the Neolithic and Chalcolithic periods – when permanent settlements and complex societies began to form across the Levant.
At Hishuley Carmel, Galili and colleagues found an elliptical structure made with a dozen upright stones that were just barely peeking above the water surface a few meters off the beach. Further investigation uncovered a second stone circle and possible remains of a third. The inside of the structures had been paved and was filled with thousands of olive pits, covered with a thin layer of clay and stones. Other installations, possibly wells or storage pits, were found nearby, but no signs of permanent habitation were uncovered, suggesting that Hishuley Carmel was mainly used as an industrial production site of sorts.
A briny pickle
To understand what exactly was going on there, the archaeologists compared these finds to those made at another submerged prehistoric site that Galili uncovered in the 1990s at Kfar Samir, just north of Hishuley Carmel.
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At this 7,000-year-old site from the late Neolithic, the archaeologists had discovered ancient wells and storage pits containing what is known in Hebrew as gefet. This is the waste from the production of olive oil, consisting mainly of crushed olive stones and pulp, which in antiquity was often used as fuel. They also found large stone basins, where the olives could have been pressed, and remains of woven baskets similar to traditional strainers used to make oil. Kfar Samir was thus declared to display the earliest evidence of olive oil production ever found.
The olive pits found at Hishuley Carmel were carbon-dated to about 500 years later, during the Chalcolithic period, but Galili and colleagues maintain that this was not just another, slightly younger, prehistoric olive oil press.
The olive pits from Hishuley Carmel were mostly whole and not fragmented, and some even had traces of fruit pulp attached to the stone, says Dr. Dafna Langgut, head of the archaeobotanical lab at Tel Aviv University and the Steinhardt Museum of Natural History. No traces of gefet or remains of tools that could have been used in the pressing of olives were found. This suggests that what was being made in those stone circles was table olives that were being pickled by using sea water or dry salt, Langgut says.
Both these materials would have been in ample supply given that 6,500 years ago the coast would have been just some 200 meters from its current location, Galili notes.
Further confirmation came from samples of pollen that were collected from the underwater silt at Kfar Samir and Hishuley Carmel. While in the earlier, oil producing site, there was a strong presence of fossilized olive pollen, this was not the case at Hishuley Carmel. This is consistent with the idea that the olives there were repeatedly washed and bathed in water as part of the curing process, Langgut says.
If this theory is correct, the stone circles at Hishuley Carmel would be the earliest evidence for the production of olives for consumption, the researchers say. So far, knowledge of ancient pickling techniques came to us not from the archaeological record but from Classical-period historians in the mid first millennium B.C.E. – some 4,000 years after the time of Hishuley Carmel.
From the Stone Age to martinis
As much as these finds were ancient – the oil production site at Kfar Samir was even older. And so were pottery shards showing residue of olive oil that were found at Ein Zippori, a Neolithic site in the Galilee, and dated to 7,000-8,000 years ago.
The possibility that humans made olive oil before they started eating the fruit is not as surprising as it may seem at first. Fresh olives are bitter and inedible unless pickled, while oil has a much higher caloric value than the fruit itself and had multiple alternative uses such as fuel for lamps or for ceremonial purposes, Galili and colleagues explain.
It is also possible that the two production processes developed at the same time at the end of the Neolithic and archaeologists will one day find even earlier evidence for edible olive production, Langgut tells Haaretz.
Be that as it may, researchers now think that they can roughly reconstruct the long history of humanity’s use of olives, “from prehistory to today’s martini,” Galili says.
Charcoal from olive wood has been identified at Paleolithic and early Neolithic sites, indicating that the tree was used as fuel but that our cavemen ancestors were likely unaware of the fruit’s properties.
“Suddenly, at the end of the Neolithic, there was a click and people understood the economic and nutritional value of the olive,” the archaeologist notes. It was then, between 8,000 to 6,500 years ago, that we apparently started making oil and pickling olives, as evidenced by the finds on the Carmel coast.
Previous research by Langgut has also shown that around 7,000 years before present there is a huge increase of olive pollen from core samples taken from the Sea of Galilee and the Dead Sea, suggesting that this was when the locals started cultivating and then domesticating wild olive plants. From the Levant, the use of olives spread across the Mediterranean to Greece, Turkey, Italy and Spain, although we don’t know if this happened independently or through contact between different populations.
Understanding when and where certain crops were first consumed and domesticated is not just a matter of culinary history – but gives us insight into the development of human societies. For example, the cultivation of olive trees, which require several years to bear fruit, signals the emergence of more stable and settled societies that recognized ownership on land, so that parents could pass on to their children the orchards on which they had likely toiled on for most of their lives, Langgut notes. In turn, the production of olive oil fueled even further complexity, contributing to economic surpluses, international trade and a more stratified society, she says.
The seas rise again
One question that remains unanswered is what happened to the people at Hishuley Carmel that forced them to abandon the site, seemingly in the middle of processing a large batch of produce.
After the peak of the last Ice Age 20,000 years ago, glaciers started to melt and the seas rose, reaching the level we know today about 6,000 years ago. The rise would have been mostly gradual, a few millimeters per year, but violent winter storms could also flood large areas at a moment’s notice, which is what may have happened at Hishuley Carmel and other prehistoric sites along the coast that are now underwater, says Galili.
The locals were certainly aware of the danger: at Tel Hreiz, a settlement a few kilometers to the south, they built a giant seawall to try to keep the waters out.
In the end, these sites may have been abandoned simply because it was no longer economically feasible to protect or rebuild them. Our prehistoric ancestors faced problems that are not dissimilar to those that coastal populations are confronted with today, as anthropic climate change pushes the seas to rise once again.
“It’s a question of adaptation versus evacuation: At some point it doesn’t make sense to invest more resources to build barriers and repair flood damage, and you ask yourself if it makes more sense to leave and rebuild more inland,” Galili concludes. “These are the dilemmas that are our ancestors faced in the past and which our children and grandchildren will have to deal with in the future.”