Lincoln Rock State Park is about 6 miles northwest of Wenatchee on Hwy 97.
Lincoln Rock State Park is one of the most popular state parks in central Washington State. It is located less than five miles from downtown Wenatchee. It was created by the recreational development required of all public utilities that were granted licenses to construct hydroelectric dams along the Columbia River in Washington and Oregon.
The precise location is less than a mile up river from the Rocky Reach Dam on the east side in Douglas County and is nicely located directly across the river from the now famous Lincoln Rock, so named many years ago when it was reported on by an eastern magazine showing a photograph of its profile. There is a monument in the park that provides a good viewing point in the picnic area. Whether one thinks it is a good likeness may be open to question. An even better view may be found at a camping site at the river’s edge. However, consideration of those occupying the location must be given.
But what is this rock that generates so much interest? On the west side of the Columbia River the rock is not very impressive and doesn’t show much of the likeness of Ol’ Abe, if any at all. So let’s talk about the rock. It is located in Chelan County at the head of Swakane Canyon at N47 32.690 W120 17.449. The canyon penetrates the area northwesterly 15 or so miles and is noted locally for its steep sides. In talking with U.S. Forest Service geologist Rich Stearns in his Wenatchee office, he explained that Lincoln Rock is largely composed of gneiss. While gneiss is a common rock located in many areas, it has different characteristics in each location. The name attributed to this particular rock is Swakane biotite gneiss (metamorphic), which sets it slightly apart from other gneiss.
Swakane Biotite Gneiss, a layered metamorphic rock, consists of quartz (44%), feldspar (41%), biotite (13%), and trace minerals (2%). The layering thickness ranges from a few inches to several feet, and is cut by quartz veins of variable thicknesses. The quartz veins have not been mineralized. The exact age of the sediments is unknown, but they are believed to be as old as 1.6 billion years. The age of metamorphism is 90 million years. These rocks lie northeast and northwest of Chiwaukum Graben, and are source rocks for the Swauk and Chumstick Formations. Erractics of Swakane Biotite Gneiss can be found along the eastside loop trail.
As the earth goes, this is an extremely old rock created by a metamorphic process. This particular rock is somewhat limited to an area covering Wenatchee, Leavenworth, and Chelan, and is the foundation of 4726’ high Burch Mountain, which rises from the Wenatchee northern city limits. The rock in its present state has been extremely compressed over the centuries and often has a black glassy look. Stearns compared it to the opposite of mica, which has a glassy, clear appearance.
Enjoy Lincoln Rock State Park and Ol’ Abe, and if you have a little exploring nature travel up the Swakane Canyon a few miles for a different take on a canyon.
References: Brent Cunderla, Area Geologist, USDI-Bureau of Land Management, Wenatchee Field Office Late Cretaceous and Early Tertiary Orogeny in the North Cascades, Ralph A. Haugerud, Edwin H. Brown, Rowland W. Tabor, Bryan J. Kriens, and Michael F. McGroder Roadside Geology of Washington, David D. Alt, Donald W. Hyndman, Mountain Press Publishing Company, Missoula, Montana 1984 Geology of the North Cascades: A Mountain Mosaic by R. Tabor and R. Haugerud, of the USGS, with drawings by Anne Crowder. It is published by The Mountaineers, Seattle
To log this Earthcache please complete the following before listing your find: 1. Where is the monument located in the park? 2. Lincoln Rock is sometimes thought to be composed of another rock. What might that common local rock be. 3. What direction is Lincoln's profile facing? 4. Post a photo of yourself, GPS in hand, at the park monument.
This cache was adopted over to Mr. Gadget #2. Your answers will be evaluated and IF THEY ARE NOT satisfactory or incorrect, I will be contacting you.