REN-DATE
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What
is REN-DATE?
Ren-Date is a
software programme for archaeomagnetic dating. It is relies on Bayesian
statistics, assuming hierarchical sampling and laboratory analysis.
What
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.
Example
The following example
is taken
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 =
65.9°
- Declination: D =
0.6°
- confidence
factor: α95
= 2.1°
- confidence parameter: κ
= 1285
- Number
of samples: N = 5
- Archaeointensity:
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
1513-1683.
(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
diagram (green
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)
Requirements
REN-DATE is available
for the disk operating system MS-WINDOWS.
Installation
Unzip the
file you have downloaded and follow the instructions on the screen.
Download
file size 1.3 Mb
*.zip
Advice
on usage
The files
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
al. 2002.
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 philippe.lanos@univ-rennes1.fr.
References
Gallet,
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.
Lanos, P.,
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
Journal International,
160,
440-476, 2005.