Types or radio dating
It can't float in mid-air, particularly if the material involved is sand, mud, or molten rock.
The principle of superposition therefore has a clear implication for the age of a vertical succession of strata.
Despite this, the "principle of cross cutting relationships" can be used to determine the sequence of deposition, folds, and faults based on their intersections -- if folds and faults deform or cut across the sedimentary layers and surfaces, then they obviously came after deposition of the sediments.
You can't deform a structure (e.g., bedding) that is not there yet!
The simplest situation for a geologist is a "layer cake" succession of sedimentary or extrusive igneous rock units arranged in nearly horizontal layers.
In such a situation, the "principle of superposition" is easily applied, and the strata towards the bottom are older, those towards the top are younger.
his document discusses the way radiometric dating and stratigraphic principles are used to establish the conventional geological time scale.
Using these principles, it is possible to construct an interpretation of the sequence of events for any geological situation, even on other planets (e.g., a crater impact can cut into an older, pre-existing surface, or craters may overlap, revealing their relative ages).
The example used here contrasts sharply with the way conventional scientific dating methods are characterized by some critics (for example, refer to discussion in "Common Creationist Criticisms of Mainstream Dating Methods" in the Age of the Earth FAQ and Isochron Dating FAQ).
A common form of criticism is to cite geologically complicated situations where the application of radiometric dating is very challenging.
This document is partly based on a prior posting composed in reply to Ted Holden.
My thanks to both him and other critics for motivating me.