Dendrochronology absolute dating method
The central rings of this older tree may then be compared with the outer rings or a yet older tree, and so on until the dates reach back into prehistory.Problems that arise are when climatic variation and suitable trees (sensitive trees react to climatic changes, complacent trees do not) are not be present to produce any significant and recognizable pattern of variation in the rings.Another problem is that there may be gaps in the sequences of available timber, so that the chronology 'floats', or is not tied in to a calendrical date or living trees: it can only be used for .Also, the tree-ring key can only go back a certain distance into the past, since the availability of sufficient amounts of timber to construct a sequence obviously decreases.Relative dating methods are used to determine only if one sample is older or younger than another.Absolute dating methods are used to determine an actual date in years for the age of an object.
Cross-dating of sites, comparing geologic strata at one site with another location and extrapolating the relative ages in that manner, is still an important dating strategy used today, primarily when sites are far too old for absolute dates to have much meaning.
The scholar most associated with the rules of stratigraphy (or law of superposition) is probably the geologist Charles Lyell.
The basis for stratigraphy seems quite intuitive today, but its applications were no less than earth-shattering to archaeological theory.
One argument in favor of the absolute dating methods presented in the preceding articles is that they should work in principle.
If they don't, then it's not just a question of geologists being wrong about geology, but of physicists being wrong about physics and chemists being wrong about chemistry; if the geologists are wrong, entire laws of nature will have to be rewritten.