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Home / Science / Researchers uncover the secret of the past with the new international carbon dating standard – HeritageDaily

Researchers uncover the secret of the past with the new international carbon dating standard – HeritageDaily



Radiocarbon dating becomes more accurate than ever after an international team of scientists refined the technique of age assessment of historical objects.

The team of researchers at the University of Sheffield, Belfast, Bristol, Glasgow, Oxford, St Andrews and Historic England, plus international colleagues, used measurements from nearly 15,000 samples from objects dating back 60,000 years ago, as part of seven-year projects.

They used the measurements to create new International Radioactive Carbon Calibration Curves (IntCal), which are the baseline in the science spectrum to accurately date artifacts and make predictions of future. Radiocarbon dating is important for fields like archeology and geological sciences to date everything from oldest modern human bones to historical climates.

Archaeologists can use that knowledge to restore historic sites or study the fall of the Neanderthals, while geologists on the Intergovernmental Panel on Climate Change (IPCC), relies on curves to learn about past climate to better understand and prepare for future changes.

Professor Paula Reimer, from Queen̵

7;s Belfast University and head of the IntCal project, said: “Radiocarbon dating has revolutionized the field of archeology and environmental science. . As we improve the baseline, we learn more about our history. IntCal calibration curves are key to helping answer major questions about the environment and where we are. “

The team of researchers has developed three curves that depend on where the dated object is found. The new curves, will be published in Radioactive carbon, are IntCal20 for the Northern Hemisphere, SHCal20 for the Southern Hemisphere and Marine20 for the world’s oceans.

Dr. Tim Heaton, from the University of Sheffield and lead author of the Marine20 curve, said: “This is a very exciting time to be working in radioactive carbon. Development in this field has helped us to truly improve our understanding. I look forward to seeing the new insights into our past that these recalculated radioactive carbon times provide.

Radiocarbon reference curves have been developed in the past 50 years, relying mainly on measurements taken from 10 to 20 years of wood-covered blocks large enough to test for radioactive carbon.

Advances in radioactive carbon testing mean updated curves instead employ small patterns, such as tree rings covering only a year, providing unprecedented accuracy and detail here in the new calibration curves. In addition, the improvement in the understanding of the carbon cycle means that curves have now been extended to the limits of radioactive carbon engineering 55,000 years ago.

Radiocarbon dating is the most frequently used approach to dating over the past 55,000 years and underpins archeological and environmental science. It was first developed in 1949. It depends on two isotopes of carbon known as 12C stabilization and 14C radioactive.

While the plant or animal is alive, it will absorb the new carbon, so there was the same ratio between the isotopes and the atmosphere at that time. But when an organism dies, it stops absorbing new carbon, the stable 12C remains but the 14C decomposes at a known rate. By measuring the ratio of 14C to 12C remaining in an object it is possible to estimate its death date.

If the level of 14C in the atmosphere is constant, this should be easy. However, it has fluctuated significantly throughout history. To accurately date organisms, scientists need a reliable historical record of its transformation to accurately convert 14C measurements into calendar age. New IntCal curves provide this link.

The curves are created based on the collection of large amounts of radioactive carbon archives in the past but can also be dated by other methods. Such archives include tree rings from 14,000 years ago, stalagmites found in caves, corals from the sea, and cores drilled from lake and ocean sediments. In total, the new curves are based on nearly 15,000 radioactive carbon measurements taken from objects 60,000 years old.

Alex Bayliss, Head of the Scientific Department of Dating at Historic England, said: “Highly accurate and precise radiocarbon dating provide the basis for public interest in historical environments and allows for better preservation and protection.

“The new curves are of international importance for archeological methods, and for conservation practices and understanding of the heritage built of wood.”

“The IntCal curve series is critical to providing a perspective on past climate, which is essential for our understanding of climate systems and as a baseline for modeling,” said Darrell Kaufman of the IPCC. change in the future. ”

SHEFFIELD UNIVERSITY

Title image credit: Public domain


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