Regression Regression: In geology, regression is the formation of a specific sequence of sedimentary and metamorphic layers, that are the result of ocean water withdrawing from the land. To illustrate, when regression occurs over millions of years, geologists find a layer of limestone, overlain by shale, and overlain again by limestone. The opposite of regression is…

“Test” Definition in Paleontology In the field of paleontology, a subsidiary of geology, the term “test” refers to the external hard part of an invertebrate.

Volcanology Volcanology: Volcanology is a branch of geology that focuses on the study of volcanos. In volcanology, geologists conduct field and laboratory investigations to learn about continental, coastal, and submarine volcanic activities. In fact, volcanology ties into many other branches of geology. For instance, a volcanologist may study the geochemistry of igneous rocks, such as…

Direct Shear Test A Direct Shear Test is a geotechnical engineering laboratory procedure that measures the shear strength value of a soil sample.

Volcanic Rock (Igneous) Definition A “Volcanic Rock” is an igneous rock that is finely crystalline and glassy (or aphanitic). To illustrate, volcanic rocks result from volcanic action at the earth’s surface. Typically, this also includes igneous intrusions that are “near-surface,” which may otherwise be considered plutonic. This action results in a final rock that is…

Dry Strength “Dry Strength” is a value that represents the strength of a soil sample, when dry, as determined by the crushing test. There is a common geotechnical engineering laboratory procedure for determining the cohesiveness or plasticity of a sample with organic or inorganic clays and silts.