Joint research project

Optical and molecular characterization of vegetable fibers for dating purposes

Project leaders
Pietro Traldi, Jorge Garcia-macedo
Agreement
MESSICO - CONACYT - Consejo Nacional de Ciencia y Tecnologia
Call
CNR/CONACYT 2012-2014
Department
Molecular Design
Thematic area
Chemical sciences and materials technology
Status of the project
New

Research proposal

Several methods have been used to date historic vegetable fibers, among those methods the most known is probably the radiocarbon dating using C14. However, in several cases the results from dating are not completely reliable, as it happens with the Turin Shroud. The development of new non-invasive dating methods and techniques will allow to study vegetable fibers with historical interest and to confirm or reject uncertain results related to the dating of historical vegetable fibers.
People involved in the collaboration is well renowned in each of the specific areas of knowledge needed for the correct development of this interdisciplinary project.
ANTECEDENTS
History. Optical dating was invented in 1984 in the physics department at Simon Fraser University, British Columbia, Canada, by David Huntley and colleagues. It was quickly used by Martin Aitken¿s laboratory in Oxford, England, but it was many years before it was adopted elsewhere. Now there are numerous laboratories around the world, though most are in Europe. In 1994 the principles behind Optical dating (and thermoluminescence dating) were extended to include surfaces last seen by the sun before buried, of carved rock types from ancient monuments and artifacts, made of granite, basalt and sandstone, and this has proved possible. The initiator of ancient buildings luminescence dating Prof. Ioannis Liritzis has shown this in several cases of various monuments. Physics. Optical dating is one of several techniques in which an age is calculated as follows: (age) = (total absorbed radiation dose) / (radiation dose rate). The radiation dose rate is calculated from measurements of the radicotive (K, U, Th and Rb) within the sample and its surroundings and the radiation dose rate from cosmic rays. The dose rate is usually in the range 0.5 ¿ 5 grays/1000 years. The total absorbed radiation dose is determined by exciting specific minerals (usually qurtz or feldspar) extracted from the sample with light and measuring the light emitted as a result. The photons of the emitted light must have higher energies than the excitation photons in order to avoid measurement of ordinary photoluminiescence. A sample in which the mineral grains have all been exposed to at least a few seconds of daylight can be said to be of zero age; when excited it will not emit any such photons. The older the sample is, the more light it emits. The minerals that are measured are usually either quartz or feldspars sand-sized grains, or unseparated silt-sized grains. There are advantages and disadvantages to using each. For quartz one normally uses blue or green excitation and measures the near ultraviolet emission. For feldspar or silt-sized grains one normally uses near infrared excitation and measures the violet emission.
JUSTIFICATION
Several methods have been used to date historic vegetable fibers, among those methods the most known is probably the radiocarbon dating using C14. However, in several cases the results from dating are not completely reliable, as it happens with the Turin Shroud. The development of new non-invasive dating methods and techniques will allow to study vegetable fibers with historical interest and to confirm or reject uncertain results related to the dating of historical vegetable fibers. This international collaboration project between scientific researchers from Mexico and Italy intends to contribute to the dating of historical vegetable fibers by means of alternative methods based on optical and molecular characterizations. People involved in the collaboration is well renowned in each of the specific areas of knowledge needed for the correct development of this interdisciplinary project.

Research goals

This international collaboration project between scientific researchers from Mexico and Italy intends to contribute to the dating of historical vegetable fibers by means of alternative methods based on optical and molecular characterizations.
Mass spectrometric techniques (in particular MALDI and MALDI imaging, but also Pyrolysis GC/MS) will be employed to determine possible changes at molecular level due to ageing (for this aim some simulated ageing by heating, photon irradiation and corona discharges will be performed). Once determined the possible molecular markers (either from the qualitative or from the quantitative points of view) their validity will be tested on ancient fiber samples (e.g. tissues from ancient Egypt) and, when their validity will be confirmed the method will be applied on the Shroud fibers. In parallel to the ms investigation, some further studies will be performed on the fiber surfaces by ESCA.

Last update: 27/11/2021