North America, Southwestern United States, Arizona, Late Triassic, ca. 225 million years ago. A thick cross section of petrified / fossilized wood from a prehistoric tree trunk. The once organic wood material fossilized- replaced by silica stone that has become colorful quartz and agate. Interestingly this chunk was not cut from a larger trunk - instead tree trunk segments will naturally separate from the rest due to erosion and seismic activity. While hard, the fossilized wood is brittle and the silica rich stone naturally breaks on a clean angle, often described like snapping chalk into pieces. Most petrified wood is cut and polished to highlight the colors, but this specimen is left almost how it would have looked when found. The exterior bark is largely preserved and once the chunk was broken off, the interior was exposed to the elements which created the weathered appearance. Size: 24" Diameter x 10" W (61 cm x 25.4 cm)

Fossilized trees from this time period come from the Chinle Formation of the southwestern USA . Due to plate tectonics, this area was near the equator on the supercontinent Pangaea during the Late Triassic, which gave it a humid, sub-tropical climate. It was a floodplain below mountains to its south and a sea to its west; as a result, massive trees washed down from the mountains and came to rest in sediments that preserved them and fossilized them. The petrification process involves the rapid burial of the tree or pieces under sediment which prevents the usual decay. Flooding and volcanic activity are usually responsible for the layers of sand, silt, and ash needed to create the right types and amount of sediment. Mineralized water can then permeate through the wood, coating cell walls and filling the intercellular cavities which then fossilizes into stone. The detailed preservation of the wood, including knots, rings, and bark, are possible because the organic wood molecules become coated and surrounded with smaller silica molecules. Nine different species of tree have been identified in the fossilized deposits in the region; this example may be Araucarioxylon arizonicum, an extinct conifer tree (and the state fossil of Arizona). Fascinatingly, the Ancestral Puebloan people who lived in the region approximately 1000 years ago used petrified wood for making tools and even building houses!

This item is heavy/oversized and will require 3rd party shipping. Please inquire about shipping cost prior to bidding.

Provenance: Private Redwood City, California, USA collection; acquired from private land in USA.

All items legal to buy/sell under U.S. Statute covering cultural patrimony Code 2600, CHAPTER 14, and are guaranteed to be as described or your money back.

A Certificate of Authenticity will accompany all winning bids.

We ship worldwide to most countries and handle all shipping in-house for your convenience.

#183100

Natural weathering and exposure to elements as expected. Abraded interior with chips and losses to exterior bark in some areas, most is intact with a nice texture. Chunk appears to be a natural and uncut segment. Great size!