Ultramafic Definition
In the study of geology, the term “ultramafic” refers to an igneous rock that comprises up to 90% mafic minerals, or more.
In the study of geology, the term “ultramafic” refers to an igneous rock that comprises up to 90% mafic minerals, or more.

Biogenic Gas Biogenic Gas: In geology, biogenic gas refers to natural gas that is the byproduct of the microbial decomposition of biological and organic matter. For instance, methane soil gas on Earth is typically a biogenic gas resulting from the decomposition of organic soil zones, landfills, marshes, and swamplands. Alternatively, natural gas can be petrogenic…

Seismic Moment Seismic Moment: In the seismology branch of geology, seismic moment represents a measure of the size of an earthquake, depending on the area of rupture, the rigidity of the rock, and the amount of slip from faulting.

Vent Riser in Methane Mitigation Vent Riser in Methane Mitigation: As per the Los Angeles Department of Building and Safety (LADBS) Methane Code, Ordinance Number 175790, a vent riser is a cast iron or ABS pipe that runs through the building walls (vertically). A vent riser is part of a methane mitigation system and has…

Leaking Underground Storage Tank (UST) Leaking Underground Storage Tank (LUST): A leaking underground storage tank (LUST) is a known case of hazardous liquid materials released into the environment, from within an underground storage tank (UST) source. The term “LUST” commonly applies to gasoline station soil contamination cases overseen by environmental regulatory agencies. Also See: Underground…

Index Fossil Definition An Index fossil, in the field of paleontology, refers to a fossil that identifies and dates the stratigraphic unit that it is observed to exist in. Index fossils can combine a wide geographic range. And they can really narrow down the classifications of most stratigraphic units.

Troposphere Troposphere: The troposphere of a terrestrial planet is the lowest member of the atmosphere. On Earth, the troposphere starts atop the ground surface and terminates roughly 10 kilometers above mean sea level. In fact, geologists understand that most of the Earth’s water vapor (clouds) exists in the troposphere. And the next member of the…