The majority of geological data comes from research on solid Earth materials. Meteorites and other extra-terrestrial natural materials are also studied by geological methods.
Mineral

Relative dating
Methods for relative dating were developed when geology first emerged as a natural science. Geologists still use the following principles today as a

The geology of an area changes through time as rock units are deposited and inserted, and deformational processes change their shapes and

With the advent of space exploration in the twentieth century, geologists have begun to look at other planetary bodies in the same ways that have been developed to study the Earth. This new field of study is called planetary geology (sometimes known as astrogeology)

Plate tectonics
In the 1960s, it was discovered that the Earth's lithosphere, which includes the crust and rigid uppermost portion of the upper mantle, is

The geological time scale encompasses the history of the Earth. It is bracketed at the earliest by the dates of the first Solar System material at 4.567 Ga (or 4.567 billion years ago) and the formation of the Earth at 4.54 Ga (4.54 billion years), which is the beginning of the

Geologists use a number of fields, laboratory, and numerical modeling methods to decipher Earth history and to understand the processes