Sunday, 20 February 2011

Petrified wood ~

Petrified wood is a fascinating remnant of the trees of the past.  I have two pieces which are very different in character.  I've included two photos of each so that you can see plenty of detail:

This one looks as if the original piece of wood has been hewn off at the top.  This is quite possible as it may not be all that old: wood can petrify in about a hundred years.


And the other side:


The wood grain of the second specimen is still clearly visible:

 

For a description of what petrified wood is and how it forms I hand the podium to Wikipedia, whose entry opens with the following:
Petrified wood (from the Greek root petro meaning "rock" or "stone"; literally "wood turned into stone") is the name given to a special type of fossilized remains of terrestrial vegetation. It is the result of a tree having turned completely into stone by the process of permineralization. All the organic materials have been replaced with minerals (mostly a silicate, such as quartz), while retaining the original structure of the wood. Unlike other types of fossils which are typically impressions or compressions, petrified wood is a three dimensional representation of the original organic material. The petrifaction process occurs underground, when wood becomes buried under sediment and is initially preserved due to a lack of oxygen which inhibits aerobic decomposition. Mineral-laden water flowing through the sediment deposits minerals in the plant's cells and as the plant's lignin and cellulose decay, a stone mould forms in its place.

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