Crop Marks Reveal Ancient Structures
RENEE MONTAGNE, HOST:
And now a drought in the U.K. has a silver lining for archaeologists. Toby Driver is an aerial archaeologist for the Royal Commission on the Ancient and Historical Monuments of Wales. He spends his time in a small aircraft flying over the country, searching for evidence of ancient structures. And the heat has made his job a little bit easier. Here's what he sees.
TOBY DRIVER: You have a shimmering sort of multi-colored fields. That's why the crops aren't ripening evenly - yellows and browns and oranges coming up in the field. And from some distance out, you can see big, dark-green circles, big, dark-green squares appearing in the fields.
MONTAGNE: Those dark-green shapes hold valuable archaeological information. Ancient structures were often surrounded by trenches for protection and drainage. Even after the structures are gone, the trenches retain moisture. So in a heat wave, when the rest of the crops turn brown, the areas on top of the structures stay green.
DRIVER: It's a bit like an X-ray of the field is revealed.
MONTAGNE: Toby Driver and his colleagues search for these markings every year. But this year is showing more structures than they've seen in decades, including some new discoveries. They paint a picture of a countryside that was much more settled and developed than previously thought. But the archaeologists have to work quickly. Thunderstorms are forecast for next week.
DRIVER: The minute these dry fields get a touch of rain, all the crops start growing again. The marks disappear. And the sites we're seeing this year may not come up again for 20 or 30 years or may never be seen.
MONTAGNE: Toby Driver and his colleagues are mapping the sites and hoping that, someday, they can be excavated. It's one unexpected side effect of more extreme weather due to man-made climate change. And discoveries like this will become more common. And if you want to see Toby Driver's photos of the new crop marks, just do what I did. Go online.
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