How about this one, it doesnt refute them per se, but it does make one consider the possibility that its not colonial
Some Reservations about the Newport Tower C-14 Dates
J. Huston McCulloch
August, 2001
This paper was published in the Midwestern Epigraphic Journal, Vol. 15, 2001, pp. 79-92.
In a widely cited 1997 paper, Johannes Hertz raises a number of arguments against a pre-Colonial origin for the famous Newport, Rhode Island Stone Tower. Hertz insists that it was modeled after the 17th century Chesterton Mill in Warwickshire, England, and points out that a 1948-9 survey by Hugh Hencken and William S. Godfrey found indisputably colonial artifacts at the bottom of a trench that surrounds the foundations. He extensively discusses the recent carbon-14 dating of the mortar by Jan Heinemeier and Högne Jungner (HJ, 1994). According to HJ, their tests indicate that the Tower was built not earlier than 1635 AD, and most likely in the range 1651-1679.
Architect Suzanne Carlson, writing already in 1996 in response to the 1994 Danish original of Hertz's article, persuasively refutes Hertz's architectural and historical objections: Even Johannes Brønsted, whom Hertz approvingly cites, admitted that "the Romanesque lines of the tower are so striking that if the tower stood in Europe, probably no one would contradict a date in the middle ages" (in Hertz 1997, p. 75). Carlson argues that Chesterton Mill was in fact built as an observatory, and only much later converted to use as a mill. She points out that the trench discovered during the 1948-9 survey makes sense as part of a colonial repair of a pre-existing tower for use as a windmill, after an earlier mill blew down in 1675. Furthermore, this trench does not work as part of the original construction, because it lacks any evidence of the presence of the staging that would have been necessary to have supported the arches. Instead, its backfill contains thousands of mortar fragments, as would be expected if it were opened as part of a repair operation.
However, Carlson admits that she, as an architect, does not understand the highly technical carbon-14 dating of the mortar. I have had a little chemical training (as an undergraduate at Caltech), and some prior familiarity with dendrocalibration, which is an important complication in the HJ paper. Perhaps they or someone else will be able to correct me, but my reading of their paper is that although the C-14 results are certainly consistent with a 17th century colonial origin for the tower, they by no means conclusively rule out a pre-Columbian origin.
and
When we scrutinize HJ's Table 1, we find some further problems with their dates. Pure calcium carbonate contains about 60% carbonate by weight. Several of their samples contain less than 10% carbonate, and on this criterion HJ reject them. However, they do not explain what is present, if not calcium carbonate. If the difference is primarily unreacted calcium hydroxide, there is a serious slow reaction problem that potentially affects all the dates. On the other hand, if the other material is primarily inert silica sand, there is no particular indication that the remaining calcium carbonate is in any way contaminated, and these samples should be no worse than any of the others. Since Accelerator Mass Spectrometry (AMS) methods are being used to measure the amount of C-14, valid results can often be obtained with even very small amounts of carbon. Small sample size might result in a large standard error, and therefore could be a valid criterion for forgoing the expense of a test, but is not per se a valid criterion for rejecting test results once they have been performed, so long as the standard error is not unusually large as a result. Thus, two samples contained 2.0% or less carbonate and were legitimately not even tested. However, sample 8 from the fireplace was tested despite containing only 5.8% carbonate, but then was inappropriately excluded from the final estimates of the age of the Tower, even though its standard error was only 70 years, less than on two of the five samples that were included in the final estimate (75 and 90).
It is very significant that the preferred first fraction of carbon extracted from the inappropriately excluded sample 8 gives a negative uncalibrated C-14 date of -110 BP, or in other words, 2060 AD! (BP = "Before Present", i.e. before 1950, the approximate date when radiocarbon dating was developed.) Because atmospheric testing of nuclear weapons since 1945 has made recent decades appear to be far in the future before calibration, this does not literally mean that the mortar tested in 1993 had atmospheric carbon from the 21st century. However, it does indicate, after calibration, that the carbon was from some date after 1945, long after the Tower is known to have been built. HJ make no comment on this impossible date for the construction, but instead merely drop it from consideration on the inappropriate criterion of the low carbonate concentration per se. In fact, sample 8 appears to exhibit a more severe case of substitution bias than I would have imagined possible, despite Hertz's assurances (1997, p. 93) that rainwater contamination "could be excluded."
and it hosted on a reputable site, Ohio-state.edu
www.econ.ohio-state.edu...
