Ginkgo Petrified Forest State ParkVantage, WA

Around 15.5 million years ago, During the Miocene Epoch, eastern Washington looked much different with its wet lush environment. It was a forest of mixed deciduous trees and conifers that received a lot of moisture from the Pacific Ocean. Today it is a high desert with layers upon layers of basalt lava flows, with very little vegetation that consists of sagebrush, shrubs and grasses. The desert environment is due to the rain shadow effect of the Olympic and Cascade mountain ranges.

Early in the Miocene a hotspot in the earth’s mantle formed under the area where Idaho, Oregon and Washington meet. The volcanic vents opened up and liquid lava poured out across the area. Scientists have determined that there were five major eruptive events with up to one hundred twenty individual flows over a period of eleven million years. In between the eruption events rich forests of alpine conifers and lowland deciduous trees grew on the newly formed volcanic soils.

In the area of Vantage, Washington, it is believed that a large lake existed where the ancestral Columbia River was possibly blocked by previous lava flows. Logs from the forests would fall into the river system and be carried downstream to be deposited in the lake. The logs would get waterlogged and sink to the bottom of the lake. It is believed that the area was a lake because of the diversity of the wood deposits from alpine and temperate lowlands. Many of the examples of petrified would are also with out roots, bark, limbs and appear water-worn.

The waterlogged wood and the ashy-mud beneath them were rapidly entombed directly in the lava flows. The waterlogged wood would not burn but instead the water would actually cool and harden the lava around it essentially encasing it. Evidence of the water environment is the pillow basalts found around the petrified wood still in formation.

The hot water that was around the water-logged wood and the percolating ground water dissolved the silica minerals from the solidified basalt and the ashy mud that lay beneath the wood. Over time these minerals would penetrate into the wood and replace parts of the wood structure. The petrified wood lay protected in the basalt for millions of years.

During the end of the last Ice Age about 15,500 to 13,500 years ago, a number of ice dams in northern Montana held back huge lakes of melted glacial water. The dams failed a number of times and produced huge flood events that scoured the eastern Washington landscape. During one of the large flood events, 1,200 feet deep water eroded the basalt exposing the petrified wood.

Outside of Vantage, Washington is the Gingko Petrified Forest State Park, and has been a popular sightseeing destination since 1930’s when George F Beck, a professor at Central Washington University researched and lobbied for the sites preservation. The petrified wood was officially found by highway workers in 1927, although the indigenous people had been using it for arrowheads and tools for thousands of years prior. Later, workers with the Civilian Conservation Corp created trails, unearthed petrified trees and built the oldest portion of the interpretive center.

There have been over fifty species found petrified at this site. Some of the species include ginkgo, sweet gum, Douglas fir, walnut, redwood, maple, spruce, elm, horse chestnut, cottonwood, magnolia, sassafras, yew and witch hazel. The park was named because it was the first location to have found the rare petrified ginkgo even though it had only found a few logs of ginkgo.

Ginkgo Petrified Forest State ParkVantage, WA

Ginkgo Petrified Forest State ParkVantage, WA

Purchased in 1997 at the Ginkgo Gem Shop outside the entrance to the Ginkgo Petrified Forest State Park.

Ginkgo Petrified Forest State ParkVantage, WA

These specimens are on display at the Stonerose Interpretive Center in Republic, WA.

They were found in Saddle Mountain near the park.

Ginkgo Petrified Forest State ParkVantage, WA

Petrified wood outside the Ginkgo Petrified Forest State Park visitor center.

Ginkgo Petrified Forest State ParkVantage, WA

Petrified wood outside the Ginkgo Petrified Forest State Park Visitor Center

Ginkgo Petrified Forest State ParkVantage, WA

Petrified wood outside the Ginkgo Petrified Forest State Park visitor center.

Ginkgo Petrified Forest State ParkVantage, WA

References

Dillhoff, Thomas A. “Fossil Forests of Eastern Washington.” Evolving Earth Foundation. 10 pages. January 19, 2010 http://www.evolvingearth.org/learnearthscience/sciencearticles0501fossilforest.htm

Johnson, Kirk. “Ginkgo Petrified Forest: Cruisin’ the Fossil Freeway.” Video. Burke Museum of Natural History and Culture, University of Washington. February 1, 2010. http://www.washington.edu/burkemuseum/cruisin/videos.php “Ginkgo/Wanapum State Park.” Wikipedia January 24, 2010. February 1, 2010. http://en.wikipedia.org/wiki/Ginkgo/Wanapum_State_Park

McDonald, Cathy. “Ginkgo Petrified Forest: Tread with wonder in ancient path of lava.” The Seattle Times July 29, 2004. http://seattletimes.nwsource.com/html/traveloutdoors/2001991169_nwwginkgo29.html