Ginkgo Petrified Forest

On the last leg of our swing through eastern and central Washington, we headed west from Moses Lake towards Seattle on I-90. Just after the bridge over the Columbia river, everyone has to pass through the small stopping point of Vantage, perched on the western bluff above the river. Very few people actually stop, except perhaps to buy gas; but we often stop to enjoy the respite and view from Ginkgo Petrified Forest State Park.

This unpretentious park and museum sit atop some more of this regions geologic drama (Wikipedia description). During the Miocene epoch, around 15.5 million years ago, the region was lush and wet, home to many plant species now extinct. A number of these trees were buried in volcanic ash, and the organic matter in the tree trunks was gradually replaced by minerals in the groundwater; the resulting petrified wood was protected for millennia by flows of basalt. Near the end of the last ice age, the catastrophic Missoula Floods (about 15,000 BC) eroded the basalt, exposing some of the petrified wood.

Around 1927, highway workers noticed the petrified wood, leading geologist George F. Beck to organize excavations. The Civilian Conservation Corps completed the excavation, built a small museum, and opened the park to the public in 1938. The petrified wood specimens in the museum were collected by Frank Walter Bobo, who was born March 4, 1894 in California. He moved to Cle Elum, Kittitas County, Washington. He became a “desert rat” digging petrified logs from the arid hills of Kittitas and Yakima counties. He was commissioned to collect, saw, and polish the specimens for the museum.

In 1963, Wanapum Dam (named for the local Indian tribe) was completed about four miles downstream, raising the water level of the Columbia River. A new Interpretive Center was constructed and about 60 petroglyphs salvaged from the rising water. Many of the salvaged petroglyphs are on display at the Interpretive Center.

The views from the bluffs easily convey the drama of the site. This one looks south to the causeway leading to the I-90 bridge and then over the river to the Wanapum dam in the far distance.

This northern view looks upstream but also reveals a small RV camping park at the river’s edge. That site was in fact the landing for the ferry that preceded the construction of the bridge. In those days, Vantage probably had more meaning to cross-state travelers than it does today.

Here, by contrast is a look directly across the river at the basalt bluffs. You can imagine how daunting they must have seemed to the first explorers and settlers.

If you look carefully above the top of the bluff you can just make out the horizontal line that is I-90 making its way east towards Spokane. What you can’t see is the full height of the cliffs and the narrower river they contained. The Wanapum dam, and the others like it along the length of the Columbia, have turned the area into a series of lakes.

 Not that lakes can’t be worth appreciating.

Columbia National Wildlife Refuge

Columbia National Wildlife Refuge is a scenic mixture of rugged cliffs, canyons, lakes, and sagebrush grasslands. Formed by fire, ice, floods, and volcanic tempest, carved by periods of extreme violence of natural forces, the refuge lies in the middle of the Drumheller Channeled Scablands of central Washington. The area reveals a rich geologic history highlighted by periods of dramatic activity, each playing a major role in shaping the land. The northern half of the refuge, south of Potholes Reservoir, is a rugged jumble of cliffs, canyons, lakes, and remnants of lava flows (Wikipedia). I took the photo below from the road atop the dam that creates the reservoir.

This part of the Scablands, known as the Drumheller Channels, is the most spectacularly eroded area of its size in the world and was designated as a National Natural Landmark in 1986.

Though it seems crude on first impression the area for parking, information, and trail head actually puts the site in perspective. You’re out there and there’s only a bare minimum of support.

On the other hand, the refuge does explain what’s going on, using a basalt column as wayfinding marker.

The information sign of course has to handle a certain amount of firepower; but it gives the big picture and maps out the hiking trails.

The formation of the area follows the same pattern as that of Palouse Falls – lava upwelling followed by centuries of wind and water erosion – but with one major addition: non-native human settlement.

The creation of lakes and wetlands would not have happened without the geologic upheavals of ages past. During the last Ice Age, sheets of ice spreading down from Canada blocked rivers with dams of ice. Occasionally—or perhaps hundreds of times—the dams failed, sending floodwaters greater than the flow of all the world’s rivers combined tearing across eastern Washington’s lava fields, gouging coulees, redistributing boulders, depositing massive sand and gravel bars, scraping the land bare in some areas and leaving behind rich soils elsewhere. Nowhere are these depressions and geologic nooks more prevalent than on the refuge.

http://www.fws.gov/refuge/Columbia/About.html

As explained on the federal website above, it’s surprising to most people outside the Northwest, that the landscape of eastern Washington is a desert. In its natural state, almost all of Columbia National Wildlife Refuge would be considered desert, with the exception of the naturally ephemeral Crab Creek. However, rather than a desert of cacti and mesquite, eastern Washington’s desert is that of shrub-steppe, with sagebrush and bunchgrasses (below).

Like most of eastern Washington, however, much of the refuge is no longer in its natural state. The construction of the Columbia Basin Project forever altered the landscape, bringing water to the desert. Seepage from irrigation structures and reservoirs created wetlands, riparian areas and small lakes on the once-dry landscape. The seasonal Crab Creek has become perennial, even providing habitat for endangered salmonids.

And water made possible other uses that could not happen otherwise. Water in the desert means an abundance of life. In its original state, the land supported coyotes, rattlesnakes, mule deer, horned larks, sage sparrows and other creatures of the shrub-steppe, although densities were limited. Water has changed all this, however. Many of the naturally occurring species can be found at higher densities (e.g., mule deer). Other species are newcomers, totally dependent on the artificial water; black-necked stilts and American avocets are some of the flashier ones. Still more species that may have made an occasional appearance can now be found in great numbers—Canada geese, northern pintails, and the refuge’s most famous visitors, lesser Sandhill cranes. It was because of this newly created wildlife oasis, and the need to provide suitable mitigation for the Columbia Basin Project, that the refuge was created in 1944 “for migratory birds and other wildlife.”

Another thing that water brings is recreational use. Without water, there wouldn’t be any fishing, waterfowl hunting, or boating on the reservoir above the dam. It’s likely that there would be less hiking, biking, horseback riding, or sightseeing; visitors are drawn to water and the vegetation and wildlife it fosters.

The Columbia Basin Project did more than create the need for, and provide water to, the refuge. It also created irrigated farmland, which secondarily provided a food source for many of the refuge’s species. The view below is from another trip through the Palouse, in an area where the introduction of roads, rails and water thoroughly transformed this part of the world.

While much of the habitat found on the refuge (most of the lakes, wetlands, springs and perennial streams) is the result of an artificial infusion of water, it is important to note that the habitats themselves are not artificial. Natural wetlands and shallow lakes can be found within the Columbia Basin. The only non-natural habitat types present are farm fields and moist soil management areas.

Palouse Falls

Palouse Falls lies on the Palouse River, about 4 miles upstream of the confluence with the Snake River in southeast Washington, United States. We visited there on a recent sightseeing trip to Walla Walla and Pullman. The falls results from some heroic geologic events in an area referred to as channeled scablands. (Some of this background is from Wikipedia)

Volcanic lava flow formed the original rolling land contours. Current understanding of this phenomena cites a ‘hot’ spot in the tectonic plate that covers the NW.

Major hot-spots have often been tracked back to flood-basalt events. In this case the hotspot’s initial flood-basalt event occurred near Steens Mountain when the Imnaha and Steens eruptions began. As the North American Plate moved several centimeters per year westward, the eruptions progressed through the Snake River Plain across Idaho and into Wyoming to its present-day location in Yellowstone Park. Consistent with the hot spot hypothesis, the lava flows are progressively younger as one proceeds east along this path.

There is additional confirmation that Yellowstone is associated with a deep hot spot (Plume Tail on map below). Using tomographic images based on seismic waves, relatively narrow, deeply seated, active convective plumes have been detected under Yellowstone and several other hot spots. These plumes are much more focused than the upwelling observed with large-scale plate-tectonics circulation. The hot spot allowed hot gasses and lava to escape from the core beneath the earth’s mantle. The hot magma would flow for hundreds of miles and deposit thick layers of granite over many thousands of years.

Later in its geologic life, the area was inundated by a series of cataclysmic floods caused by the failure of giant ice dams in the Missoula area of Montana during the Pleistocene epoch. The Missoula Floods refer to the cataclysmic floods that swept periodically across eastern Washington and down the Columbia River Gorge at the end of the last ice age. The glacial flood events have been researched since the 1920s. These glacial lake outburst floods were the result of periodic sudden ruptures of the ice dam on the Clark Fork River that created Glacial Lake Missoula. After each ice dam rupture, the waters of the lake would rush down the Clark Fork and the Columbia River, flooding much of eastern Washington and the Willamette Valley in western Oregon. After the rupture, the ice would reform, creating Glacial Lake Missoula again.

These repeated surges (tan areas above), moving at an estimated speed of 60-80 miles per hour, scoured through the layers of granite, re-routing rivers, creating new channels, and producing the rolling landscape of SE Washington and NE Oregon that we call the Palouse. In addition to carving out the Columbia Gorge, these floods also created much of today’s Willamette Valley south of Portland, including its enormous, isolated, granite island formations. The park area is characterized by interconnected and hanging flood-created coulees, cataracts, plunge pools, kolk-created potholes, rock benches, buttes and pinnacles typical of scablands. Palouse Falls State Park is located at the falls, protecting this part of the uniquely scenic area.

After all this drama, the initial impression of the park is somewhat prosaic.

To me this is one of those ‘only in America’ moments, in which it’s more important to be able to park close to the edge (and maybe view the falls through the windshield) than to leave the car in the background and approach the (protected) edge as a more vulnerable human being.

The falls are 198 ft in height. The falls consists of an upper falls with a drop of ~20 feet which lies 1,000 feet north-northwest of the main drop, and a lower falls, with a drop of 198 feet. The canyon at the falls is 377 feet deep, exposing a large cross-section of the Columbia River Basalt Group. You can clearly see the layering of the multiple basalt flows in the walls to the left of the falls. Both water and wind erosion have lowered the point at which the falls pours through the edge of the canyon; and they have left behind some interesting artifacts as well.

In a few places around the rim, clefts in the basalt were either left or opened over time. At this one, people had scrambled down to step-ledges that work their way around the perimeter of the bowl. Not exactly safe sight-seeing; and after a few people fell to their deaths, the park department fenced these areas off.

The ancestral Palouse river flowed through the currently dry Washtucna Coulee to the Columbia River. The Palouse Falls and surrounding canyons were created when the Missoula Floods overtopped the south valley wall of the ancestral Palouse River, diverting it to the current course to the Snake River by erosion of a new channel. We had driven the route up from the Snake; so it was interesting to look back in that direction.

On the cliff in the upper right of the photo there’s an observation point with a good view of the river flowing south through its dramatic landscape.

More of this landscape will show up in a later post.