Volcanic Rock (Igneous)

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 different in consistency, texture, and formation, comparing to other igneous rocks that crystalize underground. Moreover, most volcanic rocks are violently ejected or calmly extruded in the form of lava (liquid phase rock).

Examples of Volcanic Rock Types in Igneous Rock Classification

  • alkali-feldspar rhyolite
  • rhyolite (liparite)
  • dacite
  • quartz-alkali (-feldspar) trachyte
  • alkali (-feldspar) trachyte
  • foid-bearing alkali (-feldspar) trachyte
  • quartz trachyte
  • trachyte
  • foid-bearing trachyte
  • quartz latite
  • latite
  • foid-bearing latite
  • andesite
  • calc-alkaline andesite
  • andesite
  • mugearites
  • basalt
  • tephritic phonolite
  • phonolite tephrite (basanite)
  • tephrite
  • basanite
  • phonolitic foidite
  • tephritic foidite
  • foidite

Similar Posts

  • Liquefaction

    ByGeo Forward

    Liquefaction Liquefaction: Liquefaction is the process by which there is: (1) a sudden and significant decrease of shear resistance in a soil sample (cohesion-less); (2) a sudden (but temporary) increase of the pore-water pressure of a substance; and (3) a solid mass of soil that is transformed into a fluid state mass. In the event…

  • Dry Density (ρd)

    ByGeo Forward

    Dry Density (ρd) “Dry Density” (ρd) is a value that represents the density of soil when it is completely dry. To illustrate, it equates to (“bulk density” / 1) + “water content.” This is a common geotechnical engineering laboratory procedure. Dry Density Formula Dry Density = [(Bulk Density ÷ 1) + (Water Content)]

  • Effective Size (D10)

    ByGeo Forward

    Effective Size (D10) “Effective Size” (D10) is an engineering geology term. Effective Size represents a diameter that directly corresponds to the percentage, by weight, of grains that equal to 10% on the grain-size diagram. To illustrate, 10% of the soil sample particles are finer-grained, and 90% of the sample particles are coarser than the “effective…

  • Toe of a Slope

    ByGeo Forward

    “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.

  • Petrogenic Gas

    ByGeo Forward

    Petrogenic Gas Petrogenic Gas: In geology, petrogenic gas refers to natural gas that is the byproduct of the thermal decomposition of biological and organic matter. In fact, this is the same process that results in the geological formation of petroleum underground. For instance, methane soil gas hazards in Los Angeles Methane Zones are typically resulting…

  • Volatile Organic Compounds (VOCs)

    ByGeo Forward

    Volatile Organic Compounds (VOCs) Volatile Organic Compounds (VOCs): Volatile Organic Compounds are toxic organic chemicals with higher tendencies to change from liquid to vapor phase under typical earth pressures and temperatures, and usually have little-to-no water solubility characteristics. VOCs are commonly found within hydrocarbon-based fuel additives, industrial solvents, refrigerants, hydraulic fluids, degreasers, and more. These…