Above is this weeks free desktop. A few weeks back, we had one of those rare occasions where you were introduced to a new place which had never been featured here before, well get ready for other "first timer" as here's the first shot from Petrified Forest National Park. Located in northeastern Arizona, this park offers an amazing glimpse of what remains from a very different landscape which existed here 225 million years ago (Late Triassic Period) and preserves one of the largest and most colorful concentrations of petrified wood in the world. The section of petrified wood in this weeks photo was once part of a large pine-like tree setting on a lust, vast floodplain which for some reason fell, was covered with silt and volcanic ash which cut off the oxygen needed to break down the log. Groundwater rich in silica seeped into the logs replacing their normal tissues with the silica which eventually crystallized into quartz giving us what we have here. For a much more detail explaintion of this process, go the NPS site for Petrified Forest and on the index page click "In Depth", scroll down that page to a list of Site Bulletins, click "view" next to "Trees to Stone" (simple right!). This weeks photo was taken in June 2005 on a 1/2 mile trail at Crystal Forest. This short trail loops out through an amazing amount of petrified logs of all sizes. There's only a few trails to walk at Petrified Forest, they do take you into some of the log fields for a wonderful experience. I believe this park to be well worth a visit and it's possible to explore a very reasonable amount of the park in just a couple of hours.