Questions of Origin: Vikings, Vinland, and the Veracity of a Map
Gorman, Jessica, Science News
Scientists lined up on opposing sides of a decade--sold controversy this month, after the publication of two new studies concerning the authenticity of one of the world's most famous maps. If it's not a forgery, the Vinland Map contains the first known cartographic representation of the Americas. The world map, which surfaced in the 1950s, identifies a region called Vinland that resembles coastal Canada. Latin text on the map describes Vinland's discovery by the Vikings.
Both archeological evidence and ancient Viking sagas suggest that Norse explorers reached the New World around A.D. 1000, long before Christopher Columbus' voyage in 1492. Historians have wondered whether medieval Europeans were familiar with these Viking travels, and there's evidence that a scribe may have made the Vinland Map for the Council of Basel, a meeting of bishops in Switzerland in the 1430s and 1440s.
"We always assume Columbus set out on his voyages without any knowledge" of the Western Hemisphere, says Garman Harbottle of Brookhaven National Laboratory in Upton, N.Y. "Had he had a look at the Vinland Map, he would have seen it on there."
The two new reports appear to be on opposite sides of the debate but don't actually contradict each other. The authors of one report claim that the map's inks contain a 20th-century substance, making the map a modern forgery. The authors of the other say that the map's parchment dates dearly to the time of the Council of Basel.
The map could be a convincing fake drawn on old parchment. Yet the studies have renewed 4 decades of hot debate.
INK AND PARCHMENT To investigate whether the map is authentic, Robin J. H. Clark and Katherine L. Brown of the University College London used a technique called Raman microprobe spectroscopy to look for signatures of certain molecules in its ink.
Yellow lines run under the map's flaking black ink, as they do in o many documents from the Middle Ages. A widely used medieval ink called iron gallotannate can leave behind similar yellow stains containing anatase, a type of titanium dioxide.
In the Aug. 1 Analytical Chemistry, Clark and Brown report that the Vinland Map's yellow lines do, in fact, contain anatase. Yet they found no iron, only carbon, in the black ink. From these results, Clark and Brown suggest that the map's ink is carbon-based and so would have been incapable of producing anatase naturally. In an attempt to give the map authentic-looking yellow stains, a forger probably applied anatase lines before laying down carbon-ink ones, says Clark. …