GEOLOGY

Detailed explanation-1: -Yes, petrified wood is the preserved remains of a prehistoric organism (a tree) so it is a fossil. The original organic material has been replaced by quartz.

Detailed explanation-2: -Minerals, including silica dissolved from volcanic ash, absorbed into the porous wood over hundreds and thousands of years crystallized within the cellular structure, replacing the organic material as it broke down over time. Sometimes crushing or decay left cracks in the logs.

Detailed explanation-3: -petrified wood, fossil formed by the invasion of minerals into cavities between and within cells of natural wood, usually by silica (silicon dioxide, SiO2) or calcite (calcium carbonate, CaCO3).

Detailed explanation-4: -Silica in the form of opal-A, can encrust and permeate wood relatively quickly in hot spring environments. However, petrified wood is most commonly associated with trees that were buried in fine grained sediments of deltas and floodplains or volcanic lahars and ash beds.