[Bass]

Andrew- I didn't realize until looking more closely at the link in your post that those photos were from the Yellowstone area- and are buried in Absoraka ash and volcanic mudflows.  Having spent quite a bit of time in this area (Yellowstone is one of the best active mineral systems open to study), the petrified forests there contain both vertical and horizontal trees.  Horizontal trees far outnumber vertical trees in several areas.

As to ships not becoming petrified- this may be the result of two conditions: 1)  being buried in the wrong geologic environment and 2) length of time of burial.
Petrified trees are almost always (I'm sure there are exceptions) found in volcanic terrains.  Groundwaters need to be saturated with silica in order to replace the organic material with silica.  Volcanic terrains tend to enrich groundwater with silica- ash deposits and mudflows that are relatively silica rich, and volcanoes often provide heat and hydrothermal fluids to the surrounding areas.  Marine basins (sunken ships) are silt-mud rich.  These are relatively stable erosional products that shouldn't produce enriched groundwaters at normal surface temperatures.

Also, silica precipitates very slowly.  This is especially evident in Yellowstone, where travertine (calcium carbonate) terraces can grow up to 20 cm per year- silica terraces typically grow much less than 10 cm per century.  There may be too little time in human shipbuilding history to petrify ships.

[neilep (OP)]

Just want to thank you all for a really great thread !

Your posts (all of yours) do NOT go unnoticed !!...especially in MY threads !!

THANK YOU all !!!

[Alandriel]

Super pics! - Thanks guys  []

[and now of course I could kick myself. Been in Lesbos a few years ago and had no idea.....]

[paul.fr]

can i just point out, that i am not scared of let alone find wood, the least bit petrifying. Oh, and i know a joke about lesbos....thinks twice before posting joke.

[Karen W.]

LOL LOL~!