1. mineralogy and petrology
2. structural geology and volcanology
3. geomorphology and glacial geology
4. paleontology, stratigraphy and astrogeology
5. economic geology and its various branches.

Mineralogy:

An Earth science that involves the chemistry, crystal structure, and physical (including optical) properties of minerals. Studies also include the processes of mineral creation and destruction.

Petrology:

A field of geology which focuses on the study of rocks and the conditions by which they form. There are three branches of petrology, corresponding to the three types of rocks: igneous, metamorphic, and sedimentary. The word petrology itself comes from the Greek "petros", or rock.

Structural Geology:

The study of deformation of rock including breaking (fracturing and faulting) and bending or folding. More formally stated it is the branch of geology that deals with the geological processes through which the application of a force results in the transformation of a shape, arrangement or internal fabric of the rock into another shape, arrangement or internal fabric.

Volcanology:

The study of volcanoes, lava, magma and related geological phenomena. A volcanologist (also spelled vulcanologist) is a person who studies in this field.

Geomorphology:

The study of the origin of landscapes based on a cause and effect relationship. This includes the physical and chemical interactions between the earth’s surface and the natural forces acting on it, such as geology, climate, vegetation and relative base level.

Glacial Geology:

The study of land features resulting from glaciation.

Paleontology:

The study of the developing history of life on earth, of ancient plants and animals based on the fossil record, evidence of their existence preserved in rocks. This includes the study of body fossils, tracks, burrows, cast off parts, fossilized feces ("coprolites"), and chemical residues.

Stratigraphy:

A branch of geology concerned with form, arrangement, geographic distribution, chronological succession, classification, correlation and mutual relationships of rock strata, especially sedimentary.

Astrogeology:

The scientific discipline concerned with the geology of the celestial bodies such as the planets and their moons, asteroids, comets, and meteorites. Alternatively known as planetary geology or exogeology.

Economic Geology:

The branch of geology that deals with economically valuable geological materials. Economic geology is concerned with earth materials that can be utilized for economic and/or industrial purposes. These materials include precious and base metals, nonmetallic minerals, construction-grade stone, petroleum minerals, coal, and water.