A New Radiocarbon Hypothesis
John P. Jackson, Ph.D.
Turin Shroud Center of Colorado
May 5, 2008
There exist today multiple arguments of a historical/archaeological nature which
conclude that the Shroud of Turin is older than the medieval date ascribed to it by
radiocarbon dating in 1988. This has led to the proposal of various hypotheses to explain
this apparent discrepancy. One hypothesis is that the linen sample used in the
radiocarbon dating actually came from a medieval “re-weave”. While this hypothesis has
been argued on the basis of indirect chemistry, it can be discounted on the basis of
evident bandings in the 1978 radiographs and transmitted light images of STURP. These
data photographs show clearly that the banding structures (which are in the Shroud)
propagate in an uninterrupted fashion through the region that would, ten years later, be
where the sample was taken for radiocarbon dating.
Another hypothesis to explain the medieval radiocarbon date is that the Shroud sample
has been contaminated by intrinsically younger (in a radiocarbon sense) material that is
alien to the cloth such as bioplastic residues from microbial action. The problem here is
that the amount of carbon mass in such a contamination needed to skew the radiocarbon
date of the Shroud from the first to the fourteenth century would be in excess of twice
that present in the Shroud sample itself, assuming that the intrinsic radiocarbon date of
the contamination is of modern age or older.
These considerations have led our research team to consider a new contamination-
enrichment hypothesis that does not suffer from these limitations. It has been observed
that carbon monoxide in the sea-level atmosphere is significantly enriched in radiocarbon
well above that found in normal biogenic quantities derived from carbon dioxide. The
reason for this is that carbon-14 produced by cosmic ray interactions with the atmosphere
first interacts with oxygen to form 14CO with relatively high efficiency. Only later, on
the order of one to two months, does 14CO interact with OH radicals in the atmosphere
to form carbon dioxide which subsequently mixes into the atmosphere at a lower
radiocarbon ratio than that which exists in carbon monoxide.
This raises the possibility of enrichment if carbon monoxide were to slowly interact with
a sample so as to deposit its enriched carbon into the sample. We presume that textiles
could be particularly vulnerable to such enrichment by gaseous contamination, since the
gas molecules would easily diffuse around and interpenetrate into the 15 micron diameter
fibrils that are loosely spun and woven together to make up the cloth. It turns out that,
given the degree of natural radiocarbon enrichment that has been measured in
atmospheric carbon monoxide at sea-level, only about a 2% carbon contamination
relative to the overall carbon in the sample would be required to move a first century date
of the Shroud textile to the fourteenth century.
