Towards the end of 12 century, a merchant ship loaded with commercial goods sank off the coast of Java. The 1
Navigating on ancient trade routes
There was a network of trade routes that traversed the Indian Ocean and the South China Sea towards the end of 12 century, linking China to the Song Dynasty to remote ports in Japan and Southeast Asia to the east, Indonesia to the south, and the Middle East and East Africa to the west. Merchant ships transported crops, raw materials such as metals and resin, and artifacts such as pottery along these routes. Today pottery is a common sight in shipwrecks in these waters, partly because the material survives most of the other things on the sea floor, and partly because of the huge volumes that could be packed in the holds of ships merchant ships from 800 to 1.200 CE.
Archaeologists have found Chinese pottery at sites that extend from Japan to the east coast of Africa. And the excavations in southeastern China have brought to light several furnace complexes, each with hundreds of dragon furnaces: long tunnels dug into hills, which could shoot up to 30,000 pieces of pottery at a time, grouped in a few square kilometers. All of that production was aimed at exporting bowls, boxes and other ceramic containers for foreign markets. "Most of the ceramics from this region are rarely recovered from domestic facilities in China and are almost exclusively found along the maritime trade routes," archaeologist at the Field Museum Lisa Niziolek, a co-author of the study, told Ars Technica .
quality stuff, called qingbai, came from a complex called Jingdezhen in Jiangxi Province: thin vases with translucent light blue enamel on a smooth white exterior paste. But the cooker complexes throughout China provided a booming market in the qingbai knock-off. The furnaces of the Fujian province, in particular, have revealed imitations of qingbai ships with a quality lower than thousands, but with a much higher volume. Last year, a label on a ceramic box from the Java Sea Wreck traced that box to the capital of Fujian Province.
Fujian once boasted many oven complexes spread over a large area, and many of their products were very similar to the point, after all). To understand which complex furnaces supplied the cargo of the Java Sea Wreck, the archaeologist of the University of Illinois Wenpeng Xu and his colleagues had to examine the chemical footprints of the thin bluish enamels of the ancient pottery. This is where the X-ray gun, technically called portable X-ray fluorescence detector, comes into play.
Archaeologists with ray cannons
When X-rays hit something – like a 900-year-old ceramic bowl, for example – the atoms in the bowl tend to fluorescence, or they emit energy in the form of photons. Each chemical element tends to emit photons in its single frequency, thus counting photons of different frequencies, an XRF detector can "read" the chemical composition of an object. In this case, Xu and his colleagues were interested in the enamel – the thin outer layer – of the ceramics of the Java Sea sinking and four furnace complexes in southeastern China: Jingdezhen, Dehua, Huajiashan and Minqing.
When analyzing the chemical signature of some of the ceramics from the furnace complexes, he discovered that each site has its own signature, a combination of the chemical composition of local clay and the specific recipes of the potters used to prepare their pastes and enamels. Jingdezhen's ceramic glazes tend to contain more iron and less thorium than others, while Dehua's imitations have more zinc and thorium and less iron.
Xu and his colleagues scanned 60 ceramic fragments from the wreck and their chemical signatures fell clearly into four separate groups, each of which corresponds to one of the four oven complexes. It turns out that the ship destined to become the Java Sea Wreck had occupied its estate not only with a selection of real qingbai pottery, destined for foreign ports, but also a wide range of knockoff articles of various types and quantities, which Niziolek states as surprise for archaeologists.
"The qingbai articles made with precision by Jingdezhen represent only a small percentage of the load," he told Ars Technica. "Most of the qingbai goods came from the ovens of Fujian Province, which produced a huge number of export ceramics in the markets of East and Southeast Asia and other parts of the Indian Ocean. . " And this reveals much more complexity in the commercial networks of the Middle Ages Pacific than most of the usually suspect archaeologists and historians connect the potters in the hinterland of Southeast China to the markets around the Indian Ocean.
An unexpectedly long journey
Xu and his colleagues say that, according to their findings, the ship probably stopped at the port of Fuzhou to take pottery from Jingdezhen, Minqing and Huajiashan, which could have traveled by riverboat up to the port. He would then direct 180 km (111 miles) south along the Chinese coast to the Quanzhou port to take more goods from the bakery complex in Dehua. "The results of this study show that a large number of pottery in the load were produced in the furnaces in northern Fujian, which are closer to the port of Fuzhou," Niziolek told Ars.
If they are right, it means that the Middle Ages merchant captain was making a conscious decision to add time and distance to the trip to bring a wider selection of goods to the markets in Indonesia.
From China, archaeologists think that the ship was destined for the lively Javanese port of Tuban when it met its destiny. It was not the first or last ship lost in those waters. "Chinese ceramics dating back to this period have been found in the area, and there are reports that many of these come from shipwrecks off the coast," Niziolek told Ars. The crew no doubt knew the risks of a trip to the ocean, but they are unlikely to imagine that centuries later half of their cargo would be stored in a museum in a city that did not yet exist.
This underscores how much archaeologists still stand to learn from a shipwreck first dug in the 90s – its finds have been at the Field Museum since 1999. In 2011, Xu, Niziolek and their colleagues started a project on large scale to trace the sources of the objects found at the site of the wreck.
"These projects require a lot of resources and many of them have been collaborative, so it takes time to find funding, conduct research and analysis and publish the results," Niziolek told Ars. "The work done on the materials of Java Sea Shipwreck demonstrates the value of a thorough and sustained research on an existing museum collection."
Journal of Archaeological Science 2018. DOI: 10.1016 / j.jas.2018.12 .010; (Information on DOI).