Wednesday, 14 October 2009

09 Trip - SE Washington ... petrified trees

The Ginkgo Petrified Forest is located on the Colombian River. The day is hot and windy, the interpretive trail winds up a hill. Rocks covered with lichen litter the dry ground. Other than sage, there are few plants ...The only green vegetation grows dry creek beds. On the hill life is hard.
Lichen grows slowly, taking moisture from the air.We saw a few deer droppings and this little creature.
The trail has petrified trees still 'in situ' with roots in the ground.Millions of years ago, some of the largest lava flows on earth poured over this area, again and again. Parallel vents poured more than 5,000 feet of basalt over the Columbia Plateau in many layers. One of more than 300 lava flows was called the Ginkgo flow and it buried the ancient Vantage Lake under a thin layer of basalt. Water soaked logs in the lake were slowly petrified. Minerals replaced the organic cells of the trees and as they slowly turned to stone.
You can count the rings in this tree.Ice age floods occurred as the glaciers melted. Huge glacial lakes like Lake Columbia and Lake Malussa were held back by ice dams. When those dams broke, thousands of tons of water, ice and mud roared down the Columbia Gorge. The petrified forest was unearthed, trees with their roots still intact appeared. This example is blackened, perhaps by fire?Bark is recognizable. Outside the museum are petrified logs ...This example shows heavy mineral content and was polished. It resembles wood, but is stone. It is an ancient tree that in recent decades has been almost wiped out by the Dutch Elm Disease.
This site includes: ginkgo, elm, and douglas fir.

No comments: