Weekly Photo Challenge: Time (Fossilized Trees )

How much time will it take for a tree to become petrified and turned into fossils ( under the right conditions) ?

These photos were taken by my wife while travelling in the Petrified Forest National Park, Arizona in the South West part of the USA.CIMG4339

The following ( in italics) has been extracted from the Wikipedia to which credit is due:

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.CIMG4337

In Petrified Forest National Park, most of the logs in the park retained their original external form during petrification but lost their internal structure. However, a small fraction of the logs and most of the park’s petrified animal bones have cells and other spaces that are mineral-filled but still retain much of their original organic structure. With these permineralized fossils, it is possible to study the cellular make-up of the original organisms with the aid of a microscope. Other organic matter—typically leaves, seeds, cones, pollen grains, spores, small stems, and fish, insect, and animal remains—have been preserved in the park as compression fossils, flattened by the weight of the sediments above until only a thin film remains in the rock.CIMG4342

Much of the park’s petrified wood is from Araucarioxylon arizonicum trees, while some found in the northern part of the park is from Woodworthia arizonica and Schilderia adamanica trees. At least nine species of fossil trees from the park have been identified; all are extinct. The park has many other kinds of fossils besides trees. The Chinle, considered one of the richest Late Triassic fossil-plant deposits in the world, contains more than 200 fossil plant taxa. Plant groups represented in the park include lycopodss, ferns, cycads, conifers, gingkgoes, as well as unclassified forms. The park has also produced many fossil vertebrates—including giant crocodile-like reptiles called phytosaurs, large salamander-like amphibians called Buettneria, and early dinosaurs—and invertebrates, including freshwater snails and clams.CIMG4338

 

 

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