Age dating geology
As a discipline, mineralogy has had close historical ties with geology.
Minerals as basic constituents of rocks and ore deposits are obviously an integral aspect of geology.
The allied field of geophysics has several subdisciplines, which make use of different instrumental techniques.
Seismology, for example, involves the exploration of the Earth’s deep structure through the detailed analysis of recordings of elastic waves generated by earthquakes and man-made explosions.
Harder minerals scratch softer ones, so that an unknown mineral can be readily positioned between minerals on the scale.
Geologic history provides a conceptual framework and overview of the evolution of the Earth.
An early development of the subject was stratigraphy, the study of order and sequence in bedded sedimentary rocks.
Earthquake seismology has largely been responsible for defining the location of major plate boundaries and of the dip of subduction zones down to depths of about 700 kilometres at those boundaries.
In other subdisciplines of geophysics, gravimetric techniques are used to determine the shape and size of underground structures; electrical methods help to locate a variety of mineral deposits that tend to be good conductors of electricity; and paleomagnetism has played the principal role in tracking the drift of continents.