 |
|
|
|
Fri, 26 Apr, 2024
|
|
|
Pay as you go
No monthly charges. Access for the price of a phone call
Go>
Unmetered
Flat rate dialup access from only £4.99 a month Go>
Broadband
Surf faster from just £13.99 a month Go> |
Save Even More
Combine your phone and internet, and save on your phone calls
More Info> |
This weeks hot offer
24: Series 5
In association with Amazon.co.uk £26.97 |
|
Contents
 Formation
Formation - Contents
Volcanic pipes form as the result of violent eruptions of deep-origin volcanoes. These volcanoes originate at least three times as deep as most other volcanoes, and the resulting magma that is pushed toward the surface is high in magnesium and volatile compounds such as water and carbon dioxide. As the body of magma rises toward the surface, the volatile compounds transform to gaseous phase as pressure is reduced with decreasing depth. This sudden expansion propels the magma upward at rapid speeds, resulting in a shallow supersonic eruption. A useful analogy to this process is the uncorking of a warm or shaken bottle of champagne.
Kimberlite pipes
In kimberlite pipes, the eruption ejects a column of overlying material directly over the magma column, and does not form a large above-ground elevation as typical volcanoes do; instead, a low ring of ejecta known as a tuff ring forms around a bowl-shaped depression over the subterranean column of magma. Over time, the tuff ring may erode back into the bowl, leveling out the depression by filling it with washed-back ejecta.
Lamproite pipes
Lamproite pipes operate similarly to kimberlite pipes, except that the boiling water and volatile compounds contained in the magma act corrosively on the overlying rock, resulting in a broader cone of eviscerated rock (the ejection of this rock also forms a tuff ring, like kimberlite eruptions). This broad cone is then filled with volcanic ash and materials. Finally, the degassed magma is pushed upward, filling the cone. The result is a martini-glass shaped deposit of volcanic material (both solidified magma, and ejecta) which appears mostly flat from the surface. |
Change Text Size:
[A]
[default]
[A] |
 |
|
|
|
|
