Petrified Forest National Park is aUnited States national park in Navajoand Apache counties in northeasternArizona. Named for its large deposits of petrified wood. Petrified Forest National Park is known for its fossils, especially of fallen trees that lived in the Late Triassic period of the Mesozoic era, about 225 million years ago. The park's earliest human inhabitants arrived at least 8,000 years ago. By about 2,000 years ago, they were growing corn in the area and shortly thereafter building pit houses in what would become the park. Later inhabitants built above-ground dwellings called pueblos. Although a changing climate caused the last of the park's pueblos to be abandoned by about 1400 CE, more than 600 archeological sites, including petroglyphs, have been discovered in the park.
During the Late Triassic, downed trees accumulating in river channels in what became the park were buried periodically by sediment containing volcanic ash. Groundwater dissolved silica (silicon dioxide) from the ash and carried it into the logs, where it formed quartz crystals that gradually replaced the organic matter. Traces of iron oxide and other substances combined with the silica to create varied colors in the petrified wood. In Petrified Forest National Park, most of the logs in the park retained their original external form during petrification but lost their internal structure.
Photo Source: Collected from Internet
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