The Vinland Map is a drawing of Iceland, Greenland and the northeastern coast of North America that has been dated to the mid-15th century?unless it’s a forgery. If it’s real, it means that Norse explorers visited North America long before Columbus. The map, which is worth $20 million, was discovered in the 1950s and is kept at Yale University. “Many scholars have agreed that if the Vinland Map is authentic, it is the only existing cartographic representation of North America prior to Columbus,” says scholar Jacqueline Olin. Recent discoveries show it may be authentic.

In 2002, a researcher dated the map’s parchment at about 1434 using carbon testing. That means that at least the paper it?s on is the right date. Now, Olin says, “The information needed to prove that the Vinland Map is medieval rests with the ink used to draw it.”

Medieval manuscripts were written in either carbon- or iron-based inks. Erosion of the iron ink leads to yellow stains, which can be seen on the Vinland Map. British researchers who analyzed the ink with microprobe spectroscopy say it?s made up of two parts: a yellowish line overlaid with a black line that has flaked off. The black line contains carbon, meaning it could not be iron-based, and in that case, there should be no yellow staining. This would mean the yellow was put there by a clever forger.

Surprisingly, this does not mean the map is a forgery drawn on medieval paper. Olin says, “The presence of carbon in an ink is not evidence that the ink is a carbon ink. It could just as well have been iron gall ink to which carbon has been added as a colorant.” Iron-based ink was transparent until it dried, and carbon was often added to it so scribes to see their writing before the ink turned black.

Olin has also found copper, aluminum and zinc in the ink, elements which are found in medieval inks. These ingredients have only been identified in ink from that period in the last 50 years, and a forger would have had to create the map in the first half of the 20th century, without this knowledge.

So much of the past is a mystery?which explore regularly with our wonderful guests on Dreamland.

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