General Information
Petrified wood (from the Greek root petro meaning "rock" or "stone" (literally "wood turned into stone") is the name given to a special type of fossilized remains of terrestrial vegetation. It is the result of a tree or tree-like plants having completely transitioned to stone by the process of permineralization. All the organic materials have been replaced with minerals (mostly a silicate, such as quartz), while retaining the original structure of the stem tissue. Unlike other types of fossils which are typically impressions or compressions, petrified wood is a three-dimensional representation of the original organic material. The petrifaction process occurs underground, when wood becomes buried under sediment and is initially preserved due to a lack of oxygen which inhibits aerobic decomposition. Mineral-laden water flowing through the sediment deposits minerals in the plant's cells; as the plant's lignin and cellulose decay, a stone mould forms in its place. The organic matter needs to become petrified before it decomposes completely. (Source: Wikipedia)
Interestingly enough, petrified wood is the provincial stone for Alberta. The following is a list of a few other interesting "provincial" symbols for Alberta: the provincial bird is the Great Horned Owl (Bubo virginianus), the provincial fish is the Bull Trout (Salvelinus confluentus), the provincial colours are blue and gold, the provincial motto is Fortis et Liber (or Strong and Free), and the provincial flower is the Wild Rose (Rosa acicularis).
Some petrified wood from another site near Forestburg. Photo credit: strawflower.
This Earthcache
Here in the "Rose City", we were surprised to come across a specimen of petrified wood that was on display for the general public to see. At the posted coordinates, you will be standing on the sidewalk in front of the offices of the Battle River School Division (permission has been granted by the school board for this Earthcache). There is no need to go into the office or to step off of the main sidewalk to complete the logging requirements.
You will be standing in front of a petrified stump that was found by a local farmer a number of years ago in the riverbed of the Battle River. This petrified stump was removed from the riverbed by the farmer, and then donated to the original owner of this building (Camrose County), who decided to incorporate the stump into the front landscaping of the property. When the school board took over this location, they decided to keep the stump on the property, and even chose to feature the stump when they redid their landscaping a few years ago.
According to the interpretive plaque that is located right beside the petrified stump, geologists estimate the age of the original tree as being 135 million years old (although many geologists also state that petrified wood within Alberta was generally created 60 to 90 million years ago during the Cretaceous and Paleocene periods).
Logging Requirements
To log this earthcache, e-mail answers to the following questions to the cache owner to authenticate your online log. Do not post the answers online.
#1) What type of tree did this petrified stump originate from?
#2) What year was this stump removed by the farmer from the bed of the Battle River?
#3) What are the approximate dimensions of the stump in metres (length, width, height)?
#4) (Optional) Feel free to post a photo of either your GPSr or yourself with the petrified stump in the background (or alternately, of Mirror Lake opposite of the school board building). If taking a photo that includes the stump, please ensure that the interpretive plaque is not clearly visible in the photo, as this may take away the challenge for future cachers.
Websites for additional information
http://www.en.wikipedia.org/wiki/Petrified_wood
http://www3.sympatico.ca/goweezer/canada/embAlta.htm