MADRID, June 27 (EUROPA PRESS) –
A shipment of almonds has been key to dating the famous Hellenistic-era shipwreck of the Kyreniadiscovered and recovered off the northern coast of Cyprus in the 1960s.
The almonds, combined with freshly cleaned wood samples and the team’s expertise in modeling and radiocarbon dating, led Cornell University’s Tree Ring Laboratory to identify the most likely chronology for the sinking of the Kyrenia between 296 and 271 BC. C., with a strong probability that it occurred between 286 and 272 BC. c. The article is published in PLoS ONE.
The Kyrenia has a historical legacy as the first large Greek ship of the Hellenistic period to be found, in 1965, with a virtually intact hull. Between 1967 and 1969, she was excavated along with the load of her, which included hundreds of ceramic vessels, then reassembled off-site and scientifically studied.
“Kyrenia was one of the first times it was realized that this kind of rich evidence from the classical world could be found virtually intact more than 2,000 years later at the bottom of the sea, if it could be found at all,” he said. it’s a statement Stuart Manning, professor in the department of Classical Archeology and lead author of the study. “The idea of being able to dive, excavate and bring to the surface a ship from the classical era and thus directly discover this world of the past was a historic moment. “Shipwrecks are unique time capsules and amazing conservation can be achieved.”
Over the past six decades, the Kyrenia has provided archaeologists and historians with key information about the development of ancient ship technology, construction practices and maritime trade. To date, no less than three replicas of the Kyrenia have been produced and launched, and these reconstructions have provided considerable information about the ancient ships and their seaworthy performance.
However, The chronology of the Kyrenia’s provenance and the exact date of its sinking have always been vague at best.Initial efforts to date the ship were based on recovered artifacts, such as pottery on board and a small batch of coins, which initially led researchers to estimate that the ship was built and sank in the late 4th century BC.
“Classical texts and finds at port sites already told us that this era was important for widespread maritime trade and connections across the Mediterranean, an early period of globalization,” Manning said. “But the discovery of the ship Kyrenia, just under 15 meters long, probably with a crew of four, made all this very immediate and real. It produced key insights into the practicalities of the first part of a millennium of intense maritime activity in the Mediterranean, from Greece to Late Antiquity”.
The first volume of the final publication of the Kyrenia ship project, published last year, argued that the date of the shipwreck was slightly later, closer to 294-290 BC. C., but the main piece of evidence – a poorly preserved, almost illegible coin – was not airtight.
The biggest obstacle to accurately dating Kyrenia has been another 20th-century artifact: polyethylene glycol (PEG). Diggers and conservationists used to apply this petroleum-based compound to water-soaked wood to prevent it from decomposing after removing it from the oxygen-depleted environment of the ocean.
Manning’s team worked with researchers at the University of Groningen in the Netherlands to develop a new method for cleaning PEG from wood, and they demonstrated it on PEG-treated Roman-era samples from Colchester, England, which were already dated. dendrochronological (tree ring sequence) established.
“We removed the PEG from the wood, radiocarbon dated it, and showed that in each case we got a radiocarbon age consistent with the actual (known) age,” Manning said. “We basically removed 99.9% of the PEG.”
They used that technique to remove PEG from a sample of Kyrenia that Manning and his collaborators had tried, unsuccessfully, to precisely date 10 years ago. The team has also now dated a small piece of twisted wood that was rescued from Kyrenia in the late 1960s, but which was too small to include in the reconstruction, thus avoiding PEG treatment.
THOUSANDS OF ALMONDS KEPT IN AMPHORAS
Working with the Kyrenia’s original excavation team, researchers examined its various artifacts, including pottery and coins, focusing on organic materials, including an astragalus (a sheep or goat ankle bone once used for games). and divination rituals in various ancient cultures) and thousands of fresh green almonds found in some of the large amphorae, that is, ceramic jars. These “short-lived” sample materials helped define the date of the ship’s last voyage.
The team applied a statistical model combined with dendrochronology of the wood samples to obtain a much more precise level of dating than previous efforts. The model identified the most likely date range for the final voyage between 305-271 BC. C. (95.4% probability) and, most likely, 286-272 BC. C. (68.3% probability), several years more recent than current estimates.
But there was a big setback along the way. The new dates do not align with the international radiocarbon calibration curve, which is based on tree rings of known age and is used to convert radiocarbon measurements into calendar dates for the Northern Hemisphere.
Manning took a closer look at the data supporting the calibration curve, which has been assembled over many decades by dozens of laboratories and hundreds of scientists. He found that the period from 350 to 250 BC was devoid of modern accelerator mass spectrometry (AMS) radiocarbon data. Instead, the calibration curve for this period was based only on a few measurements made in the 1980s and 1990s, using an older type of radiocarbon dating technology.
With collaborators in the US and the Netherlands, the team measured single-year samples of sequoia and oak of known age to recalibrate the curve for the period 433-250 BC. That not only helped clarify a large spike in radiocarbon production caused by a minimum of solar activity centered around 360 BC. C., but also led to important revisions of the curve in the period around 300 BC. C., improvements that were fundamental for the dating of Kyrenia.
