Planetary geology, often referred to as astrogeology, employs established geologic principles to study celestial bodies within our solar system. A key objective in this field is the search for signs of life, both past and present, which has spurred numerous exploratory missions.
Sometimes known as astrogeology. Relies on known geologic principles to study other bodies of the solar system. Although planetary geologists are interested in studying all aspects of other planets, a significant focus is to search for evidence of past or present life on other worlds. This has led to many missions whose primary purpose is to examine planetary bodies for evidence of life.
Engineering geology
Engineering geology is the application of the geologic principles to engineering practice for the purpose of assuring that the geologic factors affecting the location, design, construction, operation, and maintenance of engineering works are properly addressed. Engineering Geology allows tunnels to be built without collapsing, bridges and skyscrapers to be built with sturdy foundations, and buildings to be built that will not settle in clay and mud.
Plate Tectonics
In the 1960s, a series of discoveries showed that the Earth's lithosphere is separated into a number of tectonic plates that move across the plastically deforming, solid, upper mantle, which is called the asthenosphere.There is a coupling between the movement of the plates on the surface and the convection of the mantle. This coupling between rigid plates moving on the surface of the Earth and the convecting mantle is called plate tectonics.
Structural geology
Structural geologists use microscopic analysis of oriented thin sections of geologic samples to observe the fabric within the rocks which gives information about strain within the crystalline structure of the rocks. They also perform analog and numerical experiments of rock deformation in large and small settings. Among the most well-known experiments in structural geology are those involving orogenic wedges, which are zones in which mountains are built along convergent tectonic plate boundaries.
Stratigraphy
Stratigraphers analyze samples of stratigraphic sections that can be returned from the field. Stratigraphers also analyze data from geophysical surveys that show the locations of stratigraphic units in the subsurface. In the laboratory, biostratigraphers analyze rock samples from outcrop and drill cores for the fossils found in them. These fossils help scientists to date the core and to understand the depositional environment in which the rock units formed.
Absolute Dating
Geologists can give precise dates to geologic events. They acquire these dates through radioactive isotopes as well as other methods. Before this technology, fossils were the only source of dating. Other methods include Optically stimulated luminescence and cosmogenic radionucleide dating, which are used to date erosion rates.
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Petrology
In addition to identifying rocks in the field, petrologists identify rock samples in the laboratory. Two of the primary methods for identifying rocks are through optical microscopy and by using an electron microprobe. Petrologists can also use fluid inclusion data and perform high temperature and pressure physical experiments to understand the temperatures and pressures at which different mineral phases appear, and how they change through igneous and metamorphic processes.
