Dating geology - Milf hook up site
Science, since it concerns just one universe with one set of laws, constitutes a seamless whole; we cannot unpick the single thread of absolute dating without the whole thing beginning to unravel.
So if our methods of radiometric dating are correct, then we would predict that rocks dated to the same age would have the same polarity, which they do.
This means that if we didn't have any other way of doing absolute dating, we would as a first approximation take the age of basalt on a spreading sea floor to be the distance from the rift divided by the rate of spreading.
Now if we estimate the age of the sea floor like that, then we get a good agreement with the dates produced by radiometric methods.
Or is it more likely that they are synchronized because nothing that's happened to them has affected their working?
Relative dating by definition does not produce actual dates, but it does allow us to put an order on the rocks, and so if absolute dating is to be trusted, it should agree with this order, telling us, for example, that Ordovician rocks are older than Triassic rocks; and it does.
There is no particular reason to suspect that this will turn out to be the case when it comes to the laws underlying absolute dating; nonetheless, an argument from principle alone can never be entirely convincing. You will recall from our discussion of sea floor spreading that the sea floor spreads out from mid-ocean rifts, and so ought to be younger nearer the rifts and progressively older further away from them.
What is more, we can measure the rate of spreading directly by GPS, SLR, and VLBI.
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.
So in the U-Pb method, we check that the two uranium isotopes produce concordant dates.
In the Ar-Ar method, we check that step heating yields the same date at every step.
We also see close agreement between dendrochronology and uncalibrated radiocarbon dates.