Gap-Graded The term “Gap-Graded” is used by geologists, engineers, and soil scientists in the geotechnical engineering field to describe the gradation of a soil sample, specifically when some particle sizes are missing. Aside from being “gap graded,” a soil sample can be described as “well-graded” (also referred to as poorly sorted), or “poorly graded” (or…

Dry Density (ρd) “Dry Density” (ρd) is a value that represents the density of soil when it is completely dry. To illustrate, it equates to (“bulk density” / 1) + “water content.” This is a common geotechnical engineering laboratory procedure. Dry Density Formula Dry Density = [(Bulk Density ÷ 1) + (Water Content)]

Provenance Provenance: In the field of geology, and the branch of geomorphology, the term “provenance” means the place of origin from which the constituent materials of sedimentary rock or facies are derived.

Confined Aquifer Confined Aquifer: In the hydrogeology branch of geology, a confined aquifer is an aquifer that is overlain (and underlain) by a layer of low permeability, such as clay, shale, or silty clay. In fact, the two confining layers contain the storage and flow of groundwater, such that the aquifer maintains hydraulic pressure (or…

Facies Facies: In the field of geology, the term “facies” represents a mappable, areally restricted part of a rock body that has different fossils or lithology from other contiguous beds deposited at the same time.