Geosyncline Geosyncline: In geology, a geosyncline is a large-scale indentation in the Earth’s crust that is filled with sediments. A geosyncline forms due to the gradual sinking of the Earth’s crust, causing sediment from adjacent areas to gather inside. An example of a geosyncline is the Appalachian Mountains.

Rotational Slide (Slump) Definition Rotational Slide (Slump):  A rotational slide is a type of landslide movement that occurs in a turning moment, about a pivot point that is above the center of gravity. This is typically due to an increased normal force on a slope, as well as a reduced cohesion factor of the soil…

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…

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…

Regional Metamorphism Regional Metamorphism: Metamorphism acts over large areas resulting from applied pressures of 3,000 to 10,000 bars and temperatures of 400°C to 800°C. Regional metamorphism is also referred to as dynamothermal metamorphism.