Photos by Andrew Snelling Five images of samples from the ventilation shaft.At top, is fossil wood in basalt that includes—from left to right—basalt, wood and siltstone.To see how we actually use this information to date rocks, consider the following: Usually, we know the amount, N, of an isotope present today, and the amount of a daughter element produced by decay, D*.By definition, D* = N-1) (2) Now we can calculate the age if we know the number of daughter atoms produced by decay, D* and the number of parent atoms now present, N.After digging through the thin surface sands and clays, followed by basalt, 21 metres (almost 69 feet) down they found pieces of wood entombed in the bottom basalt flow.
The incremental additions of the daughter type can then be viewed in proportion to the abundance of parent atoms. It has already been shown—7—that the number of daughter atoms present from radioactive decay , is called the initial ratio.
The imprint of a leaf was also discovered within the basalt, which was also regarded as remarkable, remembering that the enclosing rock was once molten lava erupted at 1000–1200°C (about 1800–2200°F).
So how could these tree trunks have survived being engulfed by molten lava?
Photography of the shroud by Secondo Pia in 1898 indicated that the image resembled a photographic 'negative' and represents the first modern study.
Subsequently the shroud was made available for scientific examination, first in 19 by a committee appointed by Cardinal Michele Pellegrino .
When a single body of liquid rock crystallizes, parent and daughter elements may separate so that, once solid, the isotopic data would define a series of points, such as those shown as open circles designated R.