Triassic Petrified Wood
Araucarioxylon arizonicum
Chinle Formation (Late Triassic)
Petrified Forest Member
Navajo County, Arizona
Chinle Formation (Late Triassic)
Petrified Forest Member
Navajo County, Arizona
This specimen is a very colorful and well preserved polished slab of the petrified wood cf. Araucarioxylon. This specimen has a very nice fortification agate pattern in the center. During fossilization there was a void at the center of the tree trunk that filled with agate. The slab is 11.75 by 8 inches and has excellent preserved detail. The slab is 5/8 inch thick . The specimen makes an excellent display on an easel stand.
Araucarioxylon arizonicum is an extinct species of conifer that is the state fossil of Arizona. The species is known from massive tree trunks that weather out of the Chinle Formation in desert badlands of northern Arizona and adjacent New Mexico, most notably in the 378.51 square kilometres (93,530 acres) Petrified Forest National Park. There, these trunks are locally so abundant that they have been used as building materials.
The petrified wood of this tree is frequently referred to as "Rainbow wood" because of the large variety of colors some specimens exhibit. The red and yellow are produced by large particulate forms of iron oxide, the yellow being limonite and the red being hematite. The purple hue comes from extremely fine spherules of hematite distributed throughout the quartz matrix, and not from manganese, as has sometimes been suggested.
The Chinle Formation is a collection of fluvial, lacustrine, and floodplain rocks deposited in a back-arc basin formed inland of a Late Triassic magmatic arc associated with the subduction zone off the west coast of North America. The climate during Chinle deposition has been described as humid or subhumid to semiarid. The area was however very "wet" and supported a diverse amphibian fauna.
Araucarioxylon arizonicum is an extinct species of conifer that is the state fossil of Arizona. The species is known from massive tree trunks that weather out of the Chinle Formation in desert badlands of northern Arizona and adjacent New Mexico, most notably in the 378.51 square kilometres (93,530 acres) Petrified Forest National Park. There, these trunks are locally so abundant that they have been used as building materials.
The petrified wood of this tree is frequently referred to as "Rainbow wood" because of the large variety of colors some specimens exhibit. The red and yellow are produced by large particulate forms of iron oxide, the yellow being limonite and the red being hematite. The purple hue comes from extremely fine spherules of hematite distributed throughout the quartz matrix, and not from manganese, as has sometimes been suggested.
The Chinle Formation is a collection of fluvial, lacustrine, and floodplain rocks deposited in a back-arc basin formed inland of a Late Triassic magmatic arc associated with the subduction zone off the west coast of North America. The climate during Chinle deposition has been described as humid or subhumid to semiarid. The area was however very "wet" and supported a diverse amphibian fauna.