Rock Stratigraphic Unit In the field of geology, a rock stratigraphic unit, or a lithostratigraphic unit, is a geologic formation that is identifiable by a specific lithology, as well as a consistent stratigraphic position. For example, the Monterey Formation is a rock stratigraphic unit, as it tends to consistently comprise the same gravel and sand…

Mineral Assemblages Mineral Assemblages: In the field of geology and the branch of mineralogy, the term “mineral assembles” means the minerals that compose a rock, including the different kinds and their relative abundance.

Hydro-Geology (Hydrogeology) Hydro-Geology (Hydrogeology): Hydrogeology is a branch of geology that relates to the study of the earth’s natural groundwater and surface water systems. Whereby geologists study the physical and chemical properties of unconfined aquifers, confined aquifers, river systems, lake beds, oceanwater, natural geysers, and more.

Volcanic Rock (Igneous) Definition A “Volcanic Rock” is an igneous rock that is finely crystalline and glassy (or aphanitic). To illustrate, volcanic rocks result from volcanic action at the earth’s surface. Typically, this also includes igneous intrusions that are “near-surface,” which may otherwise be considered plutonic. This action results in a final rock that is…

Petroleum Extraction Well (Oil Well) Petroleum Extraction Well (Oil Well): A petroleum extraction well, or an oil well, is a deep borehole or shaft sunk into the Earth for the exploration of oil or gas. Additionally, injection wells are often drilled to inject fluids or gas for stimulating oil recovery, re-pressurizing or pressure maintenance of…

Mafic Definition In geology, “mafic” is a term that describes an igneous rock that has an abundance of darker color minerals.