
Canyon Overlook - Bend, Oregon
Posted by:
Volcanoguy
N 44° 05.864 W 121° 20.112
10T E 633255 N 4884075
Geologic history sign at Riley Ranch Nature Reserve, Bend, Oregon.
Waymark Code: WMXA66
Location: Oregon, United States
Date Posted: 12/15/2017
Views: 1
This geology sign is located at the Canyon Overlook in Riley Ranch Nature Reserve.
Text of sign:
CANYON OVERLOOK
Multiple times over the last million years, the Deschutes River has cut new channels due to lava flows originating from Newberry Volcano. A major change in the river’s location occurred about 75,000 years ago with eruptions that created a large flow known as the ‘Basalt of Bend.’ Prior to this eruption, the Deschutes River channel was located east of Pilot Butte.
LAVA & THE DESCHUTES
Following the eruption of the ‘basalt of Bend’ the Deschutes River channel filled with lava and was blocked. The river cut a new channel along the western edge of the lava flows. Upstream from Riley Ranch, the river ran between the ‘basalt of Bend’ and Awbrey Butte.
BASALT OF BEND
In the Riley Ranch Area, the river crossed a section of the ‘basalt of Bend’ along the northwest side of Awbrey Butte. After crossing this lobe, the river was no longer flowing over hard basalts and began to cut a much wider channel in the softer gravels and welded tuff deposits.
Until about 15,000 years ago, glacial conditions prevailed and the size of the Deschutes River was much larger than it is today. Under these conditions, the river was a powerful force cutting through the Basalt lava flows with the ability to transport boulders up to 10 feet in diameter. In the wider and shallower channel of the lower Riley Ranch Area, the river slowed and deposited many of these large boulders. Over time, the river cut a canyon 100 to 180 feet deep along the western edge of Riley Ranch Nature Reserve.
In the lower Riley Ranch area, deposits of large boulders were left stranded as the river continued to down cut through the softer welded tuff deposits. The highest of these Boulder deposits can be seen atop a small Butte about 80 feet above the current river levels.”
Historic Topic: Geological
 Group Responsible for placement: City Government
 Marker Type: Trail
 Region: Central Oregon
 County: Deschutes
 State of Oregon Historical Marker "Beaver Board": Not listed
 Web link to additional information: Not listed

|
Visit Instructions:
Include your thoughts and observations pertaining to this location and your visit. Provide any additional history that you are aware of that pertains to this location. If the marker commemorates a historic building tell us what it is used for now or share with us the circumstances of an earlier visit to bring this locations history to life.
Please upload a favorite photograph you took of the waymark. Although visiting this waymark in person is the only thing required of you to receive credit for your visit, taking the time to add this information is greatly appreciated.
Be creative.