Vinland Map

Quoting Brookhaven National Laboratory/University of Arizona joint
press release, Ann B. N'Gadi <ngadia [at] scmre__si__edu> writes

>    Scientists Determine Age of First New World Map; "Vinland Map"
>    Parchment Predates Columbus' Arrival in North America
>
>    For the first time, scientists have ascribed a date - 1434 A.D.,
>    plus or minus 11 years - to the parchment of the controversial
>    Vinland Map, possibly the first map of the North American
>    continent. Collaborators from the Smithsonian Center for
>    Materials Research and Education (SCMRE), Suitland, Md., the
>    University of Arizona, Tucson, and the U.S. Department of
>    Energy's Brookhaven National Laboratory, Upton, N.Y., used
>    carbon-dating techniques to analyze the parchment on which the
>    map is drawn.  Their findings, published in the August edition
>    of the journal Radiocarbon, place the parchment of the map 60
>    years ahead of Christopher Columbus' arrival in the West Indies,
>    and provide compelling evidence that the map is authentic.
>
>    "Many scholars have agreed that if the Vinland Map is authentic,
>    it is the first cartographic representation of North America,
>    and its date would be key in establishing the history of
>    European knowledge of the lands bordering the western Atlantic
>    Ocean," said Jacqueline S. Olin, assistant director for
>    archaeometric research at SCMRE when the study began in 1995.

This new study is not conclusive concerning the authenticity of the
Vinland Map.  One should always consider the application of new
information in the context of the entire body of literature
concerning an object and also, especially when dealing with
"discovered" artifacts with no provenance, one must keep in mind the
history of forgeries.  I have summarized this relationship and
reviewed the literature with a case study in Mexicon, June 2000, v.
22, n. 3.

However, regarding this specific information about the Vinland Map
one must be skeptical.  It has long been suspected that the forger
utilized an ancient piece of leather to execute his fake (see
Baynes-Cope, 1974). Further, any acceptance of an object as
authentic must be based on its physical characteristics being
consonant with known objects with provenance. The Vinland Map also
failed this test by demonstrating under UV fluorescence different
from that of both the Tartar Relation and the Speculum Historiale.

Thus a Carbon 14 date prior to Columbus' first voyage is not
significant. What is important is the nature of the media used in
the design of the map. Walter McCrone's exhaustive study of these
materials leaves little doubt that the design is a forgery (McCrone,
1974, 1976 and 1988).   McCrone used Small Particle Analysis in the
1976 study to show that the lines of the map were composed of two
lines one devised to mimic degradation of a media (like that seen in
old maps) and one to be the inked line.  Use of TEM proved the
presence of anatase and it is illogical that this pigment could have
been produced as a degradation product as theorized by the authors
of the new article.

An earlier study by Cahill, et al., 1987 attempted to explain the
"double score" line demonstrated by McCrone (1976) and the presence
of anatase as a later redrawing of the image.  However, McCrone,
(1988) showed clearly that this is not only unlikely but physically
impossible.  The fact that there is no anatase on either of the
other maps to which the Vinland Map is supposed to be contemporary
is telling, as the degeneration hypothesis would seemingly apply to
them as well.  In fact, the variability of inks reported by Cahill,
et al. 1987 is reminiscent of a suggestion made by Hapgood
(1966:230) that the Vinland Map was a copy of authentic maps or a
rather good pastiche. Cahill, et al. also proposed disproving
McCrone on the basis of the fact that they could not always find
anatase associated with the yellow underlines which they note is due
to iron impurities.  This line of reasoning by Cahill, et al. is
based on the assumption that if the lines were originally drawn with
anatase (TiO2) and then erased that some residual would be
detectable by their methods.  But this is not logically either given
the idea that the lines might have been made separately or that
erasure could preferentially remove the anatase (which they did not
demonstrate experimentally).  This argument and the findings
reported by Cahill, et al. does support the idea of an original map
altered to include a "new world" North Africa and Spain.
Identification of an original map that would be the prototype for
such a forgery would then be the next task.  Hapgood (1966) suggests
this would be an early copy of the Andrea Bianco map of 1436.

The present study's author's suggestion that the anatase is a
degradation product is like Cahill, et al. proposal that the two
components of the lines of the Vinland Map result from aging  of two
components of the original ink rather than the two applications
demonstrated by McCrone.  But this does not explain the differences
clearly shown between the Vinland Map and the Tartar Relation and
the Speculum Historiale.  They all should show the same, or at least
similar degradation characteristics.

What is not in dispute, however, is that the authors of the present
study are ignorant of the fact of the nature of anatase and its
commercial invention in the 1920s and how the anatase on the Vinland
Map has been reported to be indistinguishable from those
precipitated anatase pigments first made in the 1920s (McCrone,
1976).  Further, anatase is a rare blue or light-yellow to brown
mineral of Ti02; other forms of TiO2 include rutile, octahidrite,
ilmenite and brookite.  The discrepancy in distribution of the
anatase by Cahill, et al. and McCrone may be the result of
differential solubilizing of the anatase during conservation
treatments, especially those performed during the first half of this
century using peroxides and the use of ammonia to remove varnishes
or during "aging" processes by the forger.  Anatase is relatively
unstable and undergoes destruction by photocatalytic oxidation
(Volz, et al., 1981) thus rather than result from degradation one
might expect less present over time given exposure.

Niccolo Caldararo
Director and Chief Conservator
Conservation Art Service


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                  Conservation DistList Instance 16:10
                 Distributed: Wednesday, July 31, 2002
                       Message Id: cdl-16-10-002
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