It is hard to think that this is a coincidence; it is also hard to think of any mechanism that could produce this agreement other than that the rocks are as old as radiometric methods tell us.
We began our discussion of absolute dating by saying that sedimentation rates could not be relied on for absolute dating.
The style of the artefact and its archaeology location stratigraphically are required to arrive at a relative date.
For example, if an artefact, say an oil lamp, is found co-located on the same floor of a governor's dwelling, and that floor can be dated in archaeology terms by reason of the patterns employed in the mosaic, then it is assumed that in relation to the floor that the lamp is of the same age.
When it comes to determining the age of stuff scientists dig out of the ground, whether fossil or artifact, “there are good dates and bad dates and ugly dates,” says paleoanthropologist John Shea of Stony Brook University.
The good dates are confirmed using at least two different methods, ideally involving multiple independent labs for each method to cross-check results.
Sometimes only one method is possible, reducing the confidence researchers have in the results. “They’re based on ‘it’s that old because I say so,’ a popular approach by some of my older colleagues,” says Shea, laughing, “though I find I like it myself as I get more gray hair.” Kidding aside, dating a find is crucial for understanding its significance and relation to other fossils or artifacts.
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.
In relative dating, the temporal order of a sequence of events is determined, allowing the investigator to surmise whether a particular object or event is older or younger than, or occurred before or after, another object or event.
In absolute or chronometric dating, the investigator establishes the age of an object or event in calendar years.
Absolute dating entails laboratory analysis of rock samples that will take a longer time.
further, the dating results will still have to be cross-checked with mapping data.