Transgression: In geology, the term transgression is the formation of a specific sequence of sedimentary and metamorphic layers, that are the result of ocean water advancing onto land. To illustrate, when transgression occurs over millions of years, geologists find a layer of sand, overlain by shale, and overlain again by limestone. The opposite of transgression is regression.
Extrusive Rocks 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…
Lumber Moisture Content Grade Lumber moisture grading is a manufacturer-provided value of moisture content, for consumers and contractors to use. There are five (5) lumber moisture content designations (S-GRN, S-DRY, KD, MC 15, and HT). Lumber Moisture Grading Lumber grade “S-GRN” stands for “surface green,” which means it is not dry, and has a moisture…
Phaneritic Definition In geology, the term Phaneritic applies to the texture of an igneous rock. A phaneritic plutonic rock has grains that are large enough to be seen with the naked eye. In fact, this indicates there was a slower rate of magmatic cooling.
Seismology Seismology: (seis·mol·o·gy) a branch of geology and geophysics that relates to earthquakes, including but not limited to their causes, effects, hazards, and mitigation techniques. Seismologists at the United States Geological Survey (USGS) use cutting-edge technology to measure seismic wave properties and geological hazards that trigger them or are triggered by them. In turn, seismology…
Wing Dam or Wing Dike A “Wing Dam” or “Wing Dike” refers to a dam that intentionally retains a fraction of the width of a flowing water source. Unlike a conventional dam, a wind dam aims to divert the path of water flow. Additionally, a wing dike can control the velocity of water flow. For…
Recurrence Interval Meaning In the field of geology, the term “Recurrence Interval” refers to the average time interval that occurs between two recorded events of seismic activity, of equal magnitude, along the same fault.
