Caledonian granite radiometric dating tests
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 simplest situation for a geologist is a "layer cake" succession of sedimentary or extrusive igneous rock units arranged in nearly horizontal layers.In order for a layer of material to be deposited, something has to be beneath it to support it.It can't float in mid-air, particularly if the material involved is sand, mud, or molten rock.The most common rocks observed in this form are sedimentary rocks (derived from what were formerly sediments), and extrusive igneous rocks (e.g., lavas, volcanic ash, and other formerly molten rocks extruded onto the Earth's surface).
However, note that because of the "principle of cross-cutting relationships", careful examination of the contact between the cave infill and the surrounding rock will reveal the true relative age relationships, as will the "principle of inclusion" if fragments of the surrounding rock are found within the infill.
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.
Words that rhyme with metamorphic What is the plural of metamorphic?
his document discusses the way radiometric dating and stratigraphic principles are used to establish the conventional geological time scale.