Summary: Alder wood has been observed to become petrified in less than 36 years under natural conditions. The wood had fallen into an overflow stream from Tateyama Hot Spring in central Japan. Water from the hot spring (70° C, pH 3) has a high silica content, and silica granules are deposited in spaces in the wood as the water seeps through it. Pieces of wood placed in the stream were nearly 40% petrified in seven years. Wood petrified in hot spring water was compared with Miocene fossil wood, and the two samples showed the same features, indicating the same process was involved in their petrification. Most petrified wood in the fossil record is associated with volcanic sediments and was probably produced in a similar manner, as hot ground water laden with volcanic ash permeated the wood.

Comment: This report confirms that petrification of wood might not take as long as had once been thought. Rapid mineralization is consistent with the excellent preservational state of some petrified wood.