Caledonian granite radiometric dating tests
A common form of criticism is to cite geologically complicated situations where the application of radiometric dating is very challenging.These are often characterised as the norm, rather than the exception.For example, wave ripples have their pointed crests on the "up" side, and more rounded troughs on the "down" side.Many other indicators are commonly present, including ones that can even tell you the angle of the depositional surface at the time ("geopetal structures"), "assuming" that gravity was "down" at the time, which isn't much of an assumption :-).In no way are they meant to imply there are no exceptions.For example, the principle of superposition is based, fundamentally, on gravity.Fundamental to stratigraphy are a set of simple principles, based on elementary geometry, empirical observation of the way these rocks are deposited today, and gravity.
They are the "initial working hypotheses" to be tested further by data.
The principle of superposition therefore has a clear implication for the age of a vertical succession of strata.
There are situations where it potentially fails -- for example, in cave deposits.
It is these highly consistent and reliable samples, rather than the tricky ones, that have to be falsified for "young Earth" theories to have any scientific plausibility, not to mention the need to falsify huge amounts of evidence from other techniques.
This document is partly based on a prior posting composed in reply to Ted Holden.
Cave deposits also often have distinctive structures of their own (e.g., spelothems like stalactites and stalagmites), so it is not likely that someone could mistake them for a successional sequence of rock units. Each of them is a testable hypothesis about the relationships between rock units and their characteristics.