Aphanitic Definition Aphanitic: In geology, the term aphanitic describes the texture of plutonic or volcanic igneous rocks, with grains that are not visible to the naked eye. In fact, an aphanitic texture is usually the result of faster cooling and solidification of liquid magma.

Listric Fault Listric Fault: In the field of geology, a listric fault refers to a fault with a curved fault plane. Most listric faults comprise a steeply dipping section near the surface. But the fault plane becomes increasingly flat with depth. Listric faults can be normal faults or reverse faults.

Reverse Fault Reverse Fault: In the field of geology, a reverse fault is a dip-slip fault in which the hanging wall moves upwards, relative to the footwall. The average dipping angle of a reverse fault ranges from 45 to 90 degrees. However, if less than 45 degrees, it becomes a “thrust fault.” Reverse faults are…

Thrust Fault Thrust Fault: In the field of geology, a thrust fault is a reverse fault in which the fault plane dipping angle is less than 45 degrees. Thrust faults are dip-slip faults, and can also be listric faults. For instance, the fault underlying the western embankment of the historical St. Francis Dam in Saugus,…

Zoning Mineralogy Definition Zoning is a variation of crystal composition that is a characteristic of feldspars. To illustrate, the center of a feldspar mineral is formed by a high-temperature phase, whereas the exterior is formed by a low-temperature phase.