Cannabaceae

Vesicular texture in volcanic rock from Tenerife
Vesicular olivine basalt from La Palma

Vesicular texture is a volcanic rock texture characterized by a rock being pitted with many cavities (known as vesicles) at its surface and inside. [1] This texture is common in aphanitic, or glassy, igneous rocks that have come to the surface of the Earth, a process known as extrusion. As magma rises to the surface the pressure on it decreases. When this happens gasses dissolved in the magma are able to come out of solution, forming gas bubbles (the cavities) inside it. When the magma finally reaches the surface as lava and cools, the rock solidifies around the gas bubbles and traps them inside, preserving them as holes filled with gas called vesicles. [2]

A related texture is amygdaloidal in which the volcanic rock, usually basalt or andesite, has cavities, or vesicles, that are filled with secondary minerals, such as zeolites, calcite, quartz, or chalcedony.[3] Individual cavity fillings are termed amygdules (American usage) or amygdales (British usage). Sometimes these can be sources of semi-precious or precious stones such as diamonds.

Rock types that display a vesicular texture include pumice and scoria.

See also[edit]

References[edit]

  1. ^ See "Elmhurst College Powerpoint via google viewer" Archived October 30, 2012, at the Wayback Machine, retrieved May 8, 2011
  2. ^ D. Armstrong, F. Mugglestone, R. Richards and F. Stratton "OCR AS and A2 Geology". Pearson Education Limited, 2008, p. 76.
  3. ^ Vesicules and Amygdule, pitt.edu, accessed 14 Sept 2021.

One thought on “Cannabaceae

  1. Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
    View the detailed Guide of Psilotum nudum: Detailed Study Of Psilotum Nudum (Whisk Fern), Classification, Anatomy, Reproduction

Leave a Reply