Underwater Archeology: Shipwreck investigated by ray gun
Off the coast of Indonesia, researchers have discovered an old wreck. With modern technology, they could now determine the origin of the cargo very precisely: 800-year-old porcelain from ancient China.
For archaeologists, finds from shipwrecks are a stroke of luck. If they are well preserved, their discovery is a bit like looking into a time capsule. Because shipwrecks not only allow an extraordinary insight into the lives of people from the past. But they also show what relationships we used with each other. After all, it was only the construction of ships that made it possible to travel long distances across the sea, to explore distant lands, to conquer or transport large quantities of goods quite easily.
A closer understanding of the trade relations of the old China could win researchers now by the employment of special technology. That's why a team headed by Wenpeng Xu from the University of Illinois and the Field Museum in Chicago examined porcelain that had once sunk with a merchant ship. Her study appeared in the Journal of Archaeological Science.
The wreck was discovered in the 1980s by fishermen off the coast of Sumatara. It probably sank sometime between the 12th and 13th centuries AD, when it could have been on the way to Java with china and about 200 tons of iron from China, archaeologists speculated.
In the video: How researchers investigate a wreck in the North Sea
Much is known about the ship but it was in bad shape. In addition, the researchers found no written sources that could have given information. After salvaging the remains of ship and cargo in the 1990s, a style and shape analysis of the loaded porcelain revealed that it may have come from the southeast of China. Here in the Empire during the Song dynasty so-called Qingbai porcelain was produced. Exactly such, partly white-blue shimmering pieces were found in the wreck.
But are they actually from the southeast of China? To answer this question, the researchers worked with a portable X-ray fluorescence device. "It looks a bit like a weapon," says Lisa Niziolek of the Field Museum, co-author of the study.
The device was used to examine 60 porcelain pieces from the find for their geochemical composition. The method not only allows a look at the components of the material, the porcelain does not even need to be destroyed. You simply hold the device to the surface and receive measurement results.
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In the method, the X-rays initially elute electrons near the inner shell of the atom. The gaps are then filled by further outward electrons. The result is the so-called fluorescence radiation, which is different for each chemical element. Precisely this measures the device and allows conclusions about the composition of the material by the different chemical signatures.
The researchers then compared this data with porcelain samples from well-known historic factories in southeastern China. The bowls, plates and cans could once have been made there, they suspected.
Ceramics from different locations have different chemical compositions because the elements differ in the clay of this region or the recipes that once used the potters to mix their clay.
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In fact, the researchers found what they were looking for. They discover similarities: Once upon a time, parts of the ship's cargo arose in the kilns of Dehua, a region near the coastal city of Quanzhou. "It's amazing that we can pinpoint the production area of material from an 800-year-old shipwreck," says study author Xu.
The study proves that the method with a portable X-ray fluorescence bring good results, the researchers write. But more important are the findings on the trade relations of the time. "We've learned to connect huge trading networks with Europeans like Magellan and Marco Polo," it says.
But in the twelfth and thirteenth centuries, there was a network in this part of the world that reached as far as Africa, as similar findings had shown. The Europeans were hardly involved. But the world at that time was much better connected than many people assume. Eventually, the porcelain was found more than 3,500 kilometers from its place of manufacture.