Reading: The Branches of Geology

As we mentioned, there are many varieties of geology. There is so much to know about our home planet that most geologists become specialists in one area. These specialties are known as branches of geology, and have specific titles. For example, a mineralogist studies minerals while a seismologist monitors earthquakes to help protect people and property from harm (figure 1).

A two part figure. Part A: A glass display case of several types of minerals. Part B: A seismograph. A paper roll inset in a device that records the strength of earthquakes.

Figure 1. (A) Mineralogists focus on all kinds of minerals. (B) Seismographs are used to measure earthquakes and pinpoint their origins.

A mountain with distinct layers in a chevron panel

Figure 2. These folded rock layers have bent over time. Studying rock layers helps scientists to explain these layers and the geologic history of the area.

Volcanologists brave molten lava to study volcanoes. Scientists who compare the geology of other planets to Earth are planetary geologists. Some geologists study the Moon. Others look for petroleum. Still others specialize in studying soil. Some geologists can tell how old rocks are and determine how different rock layers formed (figure 2). There is probably an expert in almost anything you can think of related to Earth!

Geologists might study rivers and lakes, the underground water found between soil and rock particles, or even water that is frozen in glaciers. Earth scientists also need geographers who explore the features of Earth’s surface and work with cartographers, who make maps. Studying the layers of rock beneath the surface helps us to understand the history of planet Earth.

Some Branches of Geology

As you’ve seen, different branches of geology study one particular part of earth. Since all of the branches are connected, specialists work together to answer complicated questions. Let’s look at some other important branches of geology.


Geochemistry is the study of the chemical processes which form and shape the Earth. It includes the study of the cycles of matter and energy which transport the Earth’s chemical components and the interaction of these cycles with the hydrosphere and the atmosphere.

It is a subfield of inorganic chemistry, which is concerned with the properties of all the elements in the periodic table and their compounds. Inorganic chemistry investigates the characteristics of substances that are not organic, such as nonliving matter and minerals found in the Earth’s crust.


Oceanography is the study of the composition and motion of the water column and the processes which are responsible for that motion. The principal oceanographic processes influencing continental shelf waters include waves and tides as well as wind-driven and other oceanic currents. Understanding the oceanography of shelf waters and the influence this has on seabed dynamics, contributes to a wide range of activities such as the following:

  • assessment of offshore petroleum production infrastructure
  • seabed mapping and characterisation for environmental management
  • marine biodiversity surrogacy research
  • assessment of renewable energy potential


Paleontologists are interested in fossils and how ancient organisms lived. Paleontology is the study of fossils and what they reveal about the history of our planet. In marine environments, microfossils collected within layers of sediment cores provide a rich source of information about the environmental history of an area.


Sedimentology is the study of sediment grains in marine and other deposits, with a focus on physical properties and the processes which form a deposit. Deposition is a geological process where geological material is added to a landform. Key physical properties of interest include:

  • the size and shape of sediment grains
  • the degree of sorting of a deposit
  • the composition of grains within a deposit
  • sedimentary structures.

These properties together provide a record of the mechanisms active during sediment transportation and deposition which allows the interpretation of the environmental conditions that produced a sediment deposit, either in modern settings or in the geological record.

Additional Branches

  • Benthic Ecology. Benthic ecology is the study of living things on the seafloor and how they interact with their environment.
  • Biostratigraphy. Biostratigraphy is the branch of stratigraphy that uses fossils to establish relative ages of rock and correlate successions of sedimentary rocks within and between depositional basins.
  • Geochronology. Geochronology is a discipline of geoscience which measures the age of earth materials and provides the temporal framework in which other geoscience data can be interpreted in the context of Earth history.
  • Geophysics. Information relating to various techniques including: airborne electromagnetics, gravity, magnetics, magnetotellurics, radiometrics, rock properties and seismic.
  • Marine Geochemistry. Marine geochemistry is the science used to help develop an understanding of the composition of coastal and marine water and sediments.
  • Marine Geophysics. Marine geophysics is a scientific discipline which uses the quantitative observation of physical properties to understand the seafloor and sub-seafloor geology.
  • Marine Surveying. The survey environment varies from oceanographic studies in the water column to investigating sediment and geochemical processes on the seafloor and imaging the sub-seafloor rocks. Surveys are carried over Australia’s entire marine jurisdiction, from coastal estuaries and bays, across the continental shelf and slope, to the deep abyssal plains.
  • Spectral Geology. Spectral geology is the measurement and analysis of portions of the electromagnetic spectrum to identify spectrally distinct and physically significant features of different rock types and surface materials, their mineralogy and their alteration signatures.


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