The petrified, or fossilized trees of Prince William Forest Park are believed to be that of Taxodium distichum, or what we know as the Bald Cypress. Part of this opinion is founded in the fact that the fossil trees were found in the only area within the park where Cretaceous period sediments are found, that being the northeastern corner of the park. Taxodium were proliferate during the region during that the Cretaceous period, and a side-by-side comparison of the fossils against their present-day counterparts makes the distinction rather easy. Read our full report, A Petrified Prospectus, created by Geoscientist-in-Park Volunteer, Eric Junger.
When was the petrified tree alive?
The Cretaceous Period ended approximately 65 million years ago and spanned a period of 79 million years. The Cretaceous Period was considered by many to be the height of the gigantic animal evolution, which would suddenly end in catastrophe and near desolation of 85% of all life on the planet. At the end of the Cretaceous period virtually all dinosaurs were wiped out, and debate still rages today as to how this happened. This time period is when the petrified wood at Prince William Forest Park was alive and growing as a tree.
The Cretaceous Climate
How did the wood turn to 'stone'?
In order for a plant to be fossilized, oxygen must be removed from the plants environment. Though this can happen in many ways (such as fire or volcanic explosions), in the case of our petrified wood, this occurred when the ancestral bald cypress trees fell over into the dense mud of their tropical environment. The lack of oxygen in this environment is called anaerobic. It is necessary to fossilize the wood because most bacteria, insects and other decomposers require oxygen to decompose the organic material of the tree.
Finally, through pressure and time, other minerals such as silica replace the cell material in the tree and are hardened into the petrified trees we see today.
About our petrified tree
An examination of the base of the large trunk section of the fossil tree easily demonstrates the taproot of the tree, and in the picture to the left a fine layer of quartz has developed within the inner wall of the taproot, which typically has a sort of void within its structure, allowing for the larger crystal formation over time during petrification.
How old was the tree when it fell?
There are no rings visible on the other fossil (located outside of the Turkey Run Education Center) due to the mineralization and likely fracture of the ends at time of collapse. Because these fractured ends will lead to a blurring of rings and heavier mineralization, a more accurate ring count can be made in both cases by making a cross-section of each of the specimens perpendicular to the long axis of the specimens. Calculating the circumference of the second specimen using geometric formulas it is determined that the fossil has a circumference of a minimum of 6'. The diameter is an estimate because there are deformities in the outer surface of the tree with unequal mineralization…