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Just off Hwy 20 at the historical marker, be carefull of traffic nearby. Enjoy the view
How many times have you driven right by this?
Getting to this Earthcache is easy, follow Hwy 20 east from Bend and pull over at the historical marker on the North side of the road, be carefull crossing trafffic.
Ages ago a river flowed across the high desert country in this rocky canyon. This prehistoric river drained a large lake, Lake Millican, which formed from the blocking of normal drainage in the area by lava flows. The lake covered a large area to the east encompassing an area that covered most of South, Central Oregon.
During periods of high water, the lake spilled over the edge of a ridgeline “upstream” from here and escaping water cut into the loosely consolidated lava flows and created the canyon before you. The Dry River's course can now be traced through the Oregon Badlands Wilderness north to the Crooked River. The drainage area of Dry River extends eastward to Hampton Butte and southward to the east flank of Newberry Volcano and all of Pine Mountain. During ice ages, Newberry Volcano hosted large glaciers. Runoff from these glaciers contributed to the flow of Dry River. Dry River Canyon, up to 300 feet deep, exposes layers of lava and cinders from ancient volcanoes of nearby Horse Ridge and Bear Creek Buttes.
Over the past 2 million years, climate change caused ice ages to occur again and again. During these times, increased rainfall filled many of the large closed basins in eastern Oregon, forming big bodies of water called pluvial lakes. Lakes as large as 500 to 1000 square miles filled the Harney, Klamath, Catlow, and Goose Lake basins as well as innumerable other smaller basins. Most eastern Oregon lakes, like Summer Lake, Hart Lake, and Lake Abert, are lonely salty remnants of great pluvial lakes, whose ghostly shorelines can be seen high above the modern shores. When the next ice age occurs, these ancient lakes will fill again.
A hike up the Dry River Canyon trail reveals hints of the energetic river which once flowed here. Rounded boulders, or grounded holes in bedrock caused by churning rock and water, and gravel at the bottom of the canyon show evidence of its watery past. Today, these tinajas hold water long after a rainfall and provide water for wildlife. Geological evidence is not the only clue to the canyon's past environment: several large Ponderosa pine trees linger on the canyon bottom, relics of a past ecosystem which prevailed during cooler times.
Millican Valley is presently a dry, high-desert perched basin in central Oregon, bounded to the north by lava flows and volcaniclastic ridges uplifted by the Brothers Fault Zone, a series of predominantly northwest-trending faults spanning about 300 km through central Oregon. The basin is bounded to the south and west by Quaternary lava flows and alluvial fans shed from Newberry Volcano, and to the east by a lava dome. During the Quaternary, the basin has partly filled with basaltic-andesite flows as well as alluvial fans consisting of unconsolidated gravels and tuffaceous deposits from Newberry Volcano. Millican Valley is also host to laminated sediments from a brief lacustrine occupation, and extensive dune-fields made up of tephra from the eruption of Mt. Mazama (Forming Crater Lake). Both alluvial/fluvial and lacustrine systems were active throughout the Pleistocene and were coevally active in Millican Valley during at least one point in time, perhaps forming the northernmost body of water in the Pleistocene Great Basin pluvial system. Eventual linkage to the Columbia River basin via the Crooked and Deschutes Rivers was established in the late Pleistocene by the breaching of a shallow divide at the northern margin of the basin, leading to an outburst flood and nearly complete draining of Lake Millican through the present-day Dry River Canyon.
To log this cache, send me an email with the answers to the following questions. Do not post answers in your log, unconfirmed logs will be deleted.
1. What is the name of the ridge that Dry River cut through to drain Lake Millican?
2. Once free from the Barrier, what current river does Dry River flow into?
3. What direction (N,S,E,W,NE,SE,NW,SW) was the source of the river? (reference question 1)
4. Describe the canyon.
Additional Hints
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