Time Stratigraphic Unit Definition A Time Stratigraphic Unit, or a Chronostratigraphic Unit, is a rock unit that is characterized by geological formations, during a specific period of time. This serves as a reference for all rocks formed during the same time period.

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.

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.

Thermosphere Thermosphere: The thermosphere of a terrestrial planet is the fourth and final member of the atmosphere. On Earth, the thermosphere starts atop the mesosphere at approximately 85 kilometers above mean sea level. The upper limit of the thermosphere is reasonably presumed to terminate approximately 95 kilometers above mean sea level. In fact, most of…

Dilatancy “Dilatancy” is the increase in the bulk volume of a soil substance during deformation. Dilatancy is caused by the change from a close-pack structure to an open-pack structure.

Critical Void Ratio The “Critical Void Ratio,” in soil science and geology, represents the final void ratio of a soil sample, at ultimate strength. And Critical Void Ratio is achieved by the loose and dense samples of the same soil post-shearing.