|Nothing to see here|
Warning: Nerdy Geologic Info Ahead!
As we left Issaquah heading east on I90, Dale got on the PA system to tell us about the geology of the terrain we were passing through. The interstate gains elevation east of Issaquah and descends into a valley as it approaches North Bend. Dale told us that we were driving over the meltwater channel where glacial Lake Snoqualmie (which covered the current site of North Bend) drained into glacial Lake Sammamish. He also handed out geologic maps of Washington and pointed out the Olympic-Wallowa Lineament which is clearly visible on the map and is not well understood. It is obvious to the eye but no one is sure about its significance, if any.
As we passed by Lake Easton State Park, just east of Snoqualmie Pass, we learned that we were at the southern end of a north/south strike-slip fault (similar to the San Andreas fault in California) which has slipped over 90 miles over the eons, i.e. the rocks on the west side match those on the east side 90 miles to the north. After a stop at the Indian John Hill rest area, we descended into the Kittitas Valley, described by Dale as a giant saucer filled with sediment from the surrounding mountains and hills. Hence the valley's fertile farmland.
|Our first bathroom break at the Indian John Hill rest area. The Stuart Range was looking beautiful.|
East of Ellensburg we crossed Ryegrass Summit at an elevation of 2535 feet, less than 500 feet lower than Snoqualmie Pass but with completely different terrain: sage brush and grass vs conifers and snow. Around this time we started to see outcrops of Columbia River basalt, formed about 17 million years ago from a series of massive lava flows. This rock underlies the southeastern portion of Washington, about a third of the state's total area.
We crossed the Columbia River at Vantage and turned south towards Sentinel Gap where the Columbia cuts through the Saddle Mountains. Dale told us that the east-west ridges in Eastern Washington (Saddle Mountains, Umtanum Ridge, Manastash Ridge, etc) were formed by California and Nevada pushing north against the apparently immovable rock of British Columbia. The resulting wrinkles are these ridges. The pressure is continuous and the ridges are still rising at the rate of 4-5 millimeters per year. So, during my lifetime Umtanum Ridge, for example, has risen nearly a foot! In fact it has grown a centimeter or so since I last hiked to the top of it.
We stopped at the Vernita Bridge Rest Area for an early (10:30am) box lunch. There was a bitterly cold wind blowing and most of us huddled in the lee of the restroom building where the sun reflecting off the building kept us warm. Then it was back on the bus for a 45 minute ride to the riverside trail head at Hanford Reach.
|Vernita Bridge spanning the Columbia River|
|Locust trees at the trailhead|
|One of the oldest buildings in Franklin County has seen better days|
|Description of the old building above|
|Setting out on the hike. We walked about 6 miles in total with about 300 feet of elevation gain.|
|The view to the north from the top of the bluffs|
|An erratic piece of granite from the Spokane area|
|Miscellaneous erratic rocks carried probably carried on a single iceberg. They have been lying here for over 10,000 years!|
|Mothballed World War II era reactors across the river on the Hanford Reservation. They are shut down and roofed for weather protection.|
|Dunes at Hanford Reach. Saddle Mountains are in the distance.|
|The island in the river is Locke Island, a nature preserve and sacred to the local Native Americans.|
|More dunes in the distance with Saddle Mountains as a backdrop|
|The layers you can see here are deposits from multiple ice age floods called rythmites. There are at least 15 separate floods recorded here. Beneath these layers are sediments from the ancestral Columbia River, i.e. deposits from before the floods.|
|Ice age flood deposits on top with ancestral Columbia layers below.|
|Nice colors in the late afternoon light|
The next morning, after a decent breakfast at the motel, we bussed a few miles south into the hills to the Coyote Canyon Mammoth Site. The story goes that the man who originally owned the land ran a junkyard (it's still there) and, while making room for more junk, a backhoe operator found some large bones. The junk man didn't much care and he gave a leg bone to a friend who moved to Seattle and, apparently still has the bone in his basement and refuses to give it back. Eventually some locals who are interested in paleontology heard about the find and convinced a local rancher to buy the land and give them a free hand to research the site.
The mammoth they are excavating has been carbon dated to about 17,000 years ago. It is probably male but they haven't found the pelvis yet which will tell them for sure. The theory is that the beast was drowned in the flood and the carcass was deposited here on the shore of Lake Lewis, the temporary 700 foot deep lake that lasted a week or so as the flood waters pooled upstream of Wallula Gap.
|Apparently that is a mammoth vertebrae and to the left is a rib bone|
|This lady sifts through all the dirt that is excavated looking for small bones and whatever else she can find. She is also a character.|