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phreatic

Line breaks: phre|at¦ic
Pronunciation: /frɪˈatɪk
 
/

Definition of phreatic in English:

adjective

Geology
1Relating to or denoting underground water in the zone of saturation (beneath the water table). Compare with vadose.
Example sentences
  • For example, they may occur in the continental realm above the water table - the vadose zone; or in the permanently shallow saturated zone - the phreatic zone, in either freshwater or marine conditions.
  • Conversely, grainstone fabrics of the upper sequences show the development of bladed and equant calcite cement around oolites, indicative of a primary cementation in a freshwater phreatic environment.
  • In 1990 John Cordingley found that the sump had disappeared and that the passage continued along a tube to a step up into a small phreatic rift.
1.1(Of a volcanic eruption) caused by the heating and expansion of groundwater.
Example sentences
  • This type of eruption, called a phreatic eruption, is characterized by a volcanic crater that goes beneath the level of the surrounding landscape and is encircled by a wide, low ring of volcanic debris.
  • This eruption began in July 1995 with phreatic explosions following 3 years of precursory seismic activity.
  • The characteristic tuffs of the Balder Formation originate from phreatic eruptions from the incipient continental rift zone between Eurasia and Greenland to the west.

Origin

late 19th century: from Greek phrear, phreat- 'a well' + -ic.

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