Diagenesis Diagenesis: In geology, diagenesis refers to the physical and chemical changes of a sedimentary formation when compaction and lithification occur over time.

Mineraloid Definition The term “mineraloid” refers to a natural earth substance that appears to be similar to a genuine mineral, although lacks any form of internal structure and crystal form. Nonetheless, a mineraloid does comprise true minerals within it. For instance, Fire Opal and Blue Opal are not minerals because they are amorphous (do not…

“Toe” of a Slope Definition The “toe” of a slope is essentially the bottom, or baseline section, of the soil mass comprising the slope. It is also defined as the outermost margin of displaced material during a landslide. The toe of a slope is farthest away from the head scarp.

Effective Stress (σ’) “Effective Stress” (σ’) is a geotechnical engineering term. Effective Stress is a function of “total stress,” and is due to the solid particles of soil. Effective stress represents an excess of stress above pore-water pressure (or neutral stress). Effective Stress Formula Effective Stress = Total Stress – Pore-Water Pressure.

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.

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,…