Extrusive Rocks: In the volcanology branch of geology extrusive rocks are igneous rocks that have been erupted onto the Earth’s surface, before forming and crystallizing. On the other hand, intrusive rocks form and crystallize under the Earth’s ground surface. Extrusive rocks are typically microcrystalline and aphanitic, because of the faster rate of cooling and solidification.
Rigidity Definition Rigidity – In geotechnical engineering and engineering geology, rigidity represents the ratio of the shear stress and the amount of angular rotation that it produces, within a rock sample.
Epicenter Epicenter: In the seismology branch of geology, an epicenter of an earthquake is the point on Earth’s surface that is directly above the focus (or hypocenter). It is the ground surface location overlying where an earthquake rupture originates within a dip-slip fault or strike-slip fault. Shortly after an earthquake, United States Geological Survey (USGS)…
Twinning Definition Twinning is the observed intergrowth of multiple crystals in a symmetrical fashion. This term applies to the examination of rock thin sections, in the field of optical mineralogy.
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)]
Geology Geology: Geology is a field of science relating to the earth, including but not limited to the earth’s resources, physical processes, chemical properties, history, and future. Additionally, the science of geology includes the study of other terrestrial planets, such as Mercury, Venus, or Mars. Branches of Geology There are numerous branches of geology that…
Environmental Professional Definition Environmental Professional: As per the EPA’s All Appropriate Inquiries Rule, an environmental professional is an environmental consultant that has an accredited education in earth or natural science, at least five years of formal training under another environmental professional, a professional state license, and maintains expert knowledge in the environmental geology, sustainability, and…
