Editing Vinland Map (section)

=== Dating of parchment ===
[[Radiocarbon dating]], begun in 1995 by physicist Douglass Donahue and chemists Jacqueline Olin and Garman Harbottle, placed the origin of the [[parchment]] somewhere between 1423 and 1445. The initial results were confusing because the unknown substance the British Museum had found across the whole map, effectively ignored by later researchers who were concentrating on the ink, turned out to be trapping tiny traces of [[Nuclear fallout|fallout]] deep within the parchment from 1950s [[nuclear tests]]. Although there was none of this 1950s substance on top of the ink, further tests, starting with a detailed chemical analysis, were needed to confirm whether the lines were drawn after it soaked into the parchment.<ref>{{cite journal |author1=Donahue, D. J. |author2=Olin, J. S. |author3=Harbottle G. |title=Determination of the Radiocarbon Age of Parchment of the Vinland Map |journal=Radiocarbon |volume=44 |pages=45–52 |year=2002 |issue=1 |doi=10.1017/S0033822200064651 |doi-access=free |bibcode=2002Radcb..44...45D }}</ref>

In 2008, Harbottle's attempt to explain a possible medieval origin for the ink was published, but he was shown by Towe and others to have misunderstood the significance of the various analyses, rendering his theory meaningless.<ref name=towe08/><ref name=brownclark/>