Malheur Butte EarthCache
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The EarthCache location is a roadside information area. Local roads can be used to get an even better close-up view as they allow you to drive right next to Malheur Butte. It is my understanding that Malheur Butte is private property so please do not venture onto the Butte.
Malheur Butte
Malheur Butte is an extinct volcano located in Malheur County, Oregon. Between 20 and 15 million years ago, the region from north-central Washington to northeastern California experienced a series of volcanic eruptions and basalt lava floods that covered thousands of square miles. Malheur Butte was likely formed during this period. These ancient lava floods and volcanic eruptions often dammed streams, creating lakes and swamps that may have lasted for millions of years before filling with sediment or draining as erosion slowly lowered their outlets. The western Snake River plain contained many such lakes, and geologists believe that between 8 and 2 million years ago ancient "Lake Idaho" covered much of the Snake River Valley from about Twin Falls, Idaho toward the northwest to just past Ontario, Oregon. As the water level rose from the melting of glaciers Lake Idaho filled with silt and water. Malheur Butte, already a dormant volcano, and the rest of the Snake River plain was covered with water and lake bed sediment. Eventually the higher water levels forced some water south into Nevada and some to flow north. A few miles northeast of this location the Malheur River, which flows past Malheur Butte on the south side, enters the Snake River. The Snake River gorge, known as Hells Canyon, thus became the northern water outlet of ancient Lake Idaho. During the last 2 million years the Malheur River and other eroding forces slowly exposed and shaped Malheur Butte, a local landmark.
In the graphic below you can see the six types of volcanos and how they are formed.
This next graphic shows the type of volcanic material emitted from volcanoes.
To log this Earthcache you must physically visit this location and answer the following questions. Email the answers to me. Photos of Malheur Butte are welcome.
(1) Estimate the height of Malheur Butte (not the elevation).
(2) From your observation of the volcano and what you learned from the first graphic: what type of volcano is Malheur Butte?
(3) From your observations and what you learned from the second grapgic about types of lava: what type of volcanic material do you see on Malheur Butte?
(4) Do you believe that the composition of the sedimentary soil high up on the Butte is the same or different than the soil in the surrounding farm land? Why is that?
(5) Why is the soil in the surrounding area good for growing crops?
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Congratulations to 6ftzpr&1/2zip for being FTF!
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