Ren-Date is a
software programme for archaeomagnetic dating. It is relies on Bayesian
statistics, assuming hierarchical sampling and laboratory analysis.
does REN-DATE do?
Having calculated the
mean direction and/or the intensity of an archaeological artefact
(strictly following the hierarchy), REN-DATE calculates probability
densities of possible dates for each geomagnetic field element, by
comparison with a secular variation mastercurve. The archaeomagnetic
dating is obtained by combining all probability densities, in order to
find the most probable solution.
The following example
from Kovacheva (2004) and
concerns one kiln from the archaeological site Serdica that been dated
by coin findings, belonging to the reign of Emperor Justinian II (i.e.
565-578 AD). However, archaeologists suppose that this kiln may have
been in use during the Ottoman Empire.
The measured average remanence direction archaeointensity is:
- Inclination: I =
- Declination: D =
- confidence parameter: κ
of samples: N = 5
F = (60.75 ± 5.45)
μT from two accepted samples
Figure A: The horizontal solid
lines in the figures below correspond to the measured site mean
inclination, declination and archaeointensity, the parallel dashed
lines correspond to the error. The Bulgarian secular variation
mastercurve is plotted with its errors. The measured geomagnetic field
elements (I,D,F) meet several times the secular variation curve,
resulting in different multiple probability intervals of possible ages (black shaded areas). If the
probability intervals of all three geomagnetic elements are combined (Figure B), the most probable age of the last heating is
(from Kovacheva et al., 2004)
Figure B: Probability densities
of possible ages for inclination (I), declination (D) and
archaeointensity (F). Their combination is displayed in the lowermost
shaded areas). The highest probability has the last age interval (1513
- 1683) which confirms the supposition of the archaeologists, that this
kiln was last in used during the Ottoman Empire.
(from Kovacheva et al., 2004)
REN-DATE is available
for the disk operating system MS-WINDOWS.
file you have downloaded and follow the instructions on the screen.
file size 1.3 Mb
GAL2002D.REF and GAL2002I.REF concern the French secular variation
master curve for declination and inclination, respectively, reduced to
Paris according to the synthesised data from Gallet et
Both files were preliminary calculated using the programme RenCurve,
but do currently not take into account the errors in time. For further
question please contact Philippe Lanos email@example.com.
Y., Genevey, A. and M. Le Goff, Three millennia of directional
variation of the Earth's magnetic field in western Europe as revealed
by archaeological artefacts, Physics
of the Earth and Planetary Interiors, 131, 81-89, 2002.
Bayesian inference of calibration curves: application to
archaeomagnetism, in: Buck, C. & A. Millard (eds.), Tools for constructing chronologies:
crossing disciplinary boundaries, Springer-Verlag, London, Vol.
177, pp. 43-82, 2004.
Lanos, P., Le Goff, M., Kovacheva, M. and E. Schnepp, Hierarchical
modelling of archaeomagnetic data and curve estimation by moving
average technique, Geophysical