Pollen Trapped in Pitch Tracks Repairs Made to Ancient Ship

STRASBOURG, FRANCE—According to a statement released by Frontiers, the protective coatings on a 2,200-year-old Roman shipwreck found off the coast of Croatia were made of pine tar, or pitch, and a mixture of pine tar and beeswax. Beeswax was added to heated tar to make a mixture known to Greek shipbuilders as zopissa, which is more flexible and easier to apply. In addition to analyzing the chemical makeup of the coatings on the ship, archaeometrist Armelle Charrié of Strasbourg University and her colleagues examined pollen trapped in the sticky pitch at the time of application. “Analysis of pollen in the coating made it possible to identify the plant taxa present in the immediate environment during the construction or repairs of the ship,” Charrié said. The pollen in the ship’s coating suggest that the vessel had been repaired in several different locations around the Mediterranean and Adriatic Seas. The stern and central part of the ship were covered with the same coating, but three patches at the bow were different from each other. “While it seems obvious that ships sailing long distances need repairs, it’s simply not easy to demonstrate this,” Charrié said. “Pollen has been very useful in identifying different coatings where the molecular profiles were identical,” she added. Read the original scholarly article about this research in Frontiers in Materials. To read about a vessel found at the bottom of the Black Sea, go to "Ancient Shipwreck," one of ARCHAEOLOGY's Top 10 Discoveries of 2018.