Recap
The Fryrear Canyon area, which is now BLM land, is named after a Central Oregon family that settled in the area in the late 1800's. There was rain the day prior that settled the dust, so we enjoyed a 6 mile hike with Derek leading us on how to solve the mystery of how this dry canyon was formed. Our first stop was at a rock outcropping of Plainview Basalt which is characterized by white mineral flecks that are plagioclase feldspar phenocrysts. This basalt flow's age is unknown but it is younger than the 650,000 year old Desert Spring Tuff that it overlies. Next stop was a beautiful example of Desert Springs Tuff outcropping in an abandoned, small quarry that shows its candy cotton pink color due to oxidation of the small amount of iron in the rock. We moved on to study the Deschutes Formation Basalt that is much older, in the range from 4-7.5 million years old. Down in the canyon we saw rounded rocks which are evidence that flowing water likely eroded this canyon. There are actually two sub parallel canyons. One main canyon is entirely in the Deschutes Formation, the other tributary canyon is Plainview basalt on one wall and Deschutes Fm on the other. The water eroded a weak point where the two flows meet causing the two canyons to form. It was a great day learning and appreciating more of the Central Oregon landscape. Thanks to Joan Gallinger for this recap
The Fryrear Canyon area, which is now BLM land, is named after a Central Oregon family that settled in the area in the late 1800's. There was rain the day prior that settled the dust, so we enjoyed a 6 mile hike with Derek leading us on how to solve the mystery of how this dry canyon was formed. Our first stop was at a rock outcropping of Plainview Basalt which is characterized by white mineral flecks that are plagioclase feldspar phenocrysts. This basalt flow's age is unknown but it is younger than the 650,000 year old Desert Spring Tuff that it overlies. Next stop was a beautiful example of Desert Springs Tuff outcropping in an abandoned, small quarry that shows its candy cotton pink color due to oxidation of the small amount of iron in the rock. We moved on to study the Deschutes Formation Basalt that is much older, in the range from 4-7.5 million years old. Down in the canyon we saw rounded rocks which are evidence that flowing water likely eroded this canyon. There are actually two sub parallel canyons. One main canyon is entirely in the Deschutes Formation, the other tributary canyon is Plainview basalt on one wall and Deschutes Fm on the other. The water eroded a weak point where the two flows meet causing the two canyons to form. It was a great day learning and appreciating more of the Central Oregon landscape.
Thanks to Joan Gallinger for this recap
Led by John Stockham & Derek Loeb
Sunday, November 5
10:00 AM - 3 PM
Please join John Stockham & Derek Loeb for a geo-exploration trip focused on the geology of the late Pleistocene Desert Springs Tuff and Basalt of Plainview and how their deposition was controlled by the paleogeography of the older Deschutes Formation. Fryrear Canyon is one of many dry canyons in Central Oregon that were eroded during wetter times probably related to glacial cycles. Fryrear Canyon is closed during raptor nesting season from Feb. 1 - Aug. 31. We will be hiking about 6 miles, some of which will be off trail, with only minor elevation changes.
Trip is limited to 15 participants. Please contact Derek Loeb, DerekLoeb@gmail.com with any questions. There will be a ride share meetup option for Bend area participants.
Central Oregon Geoscience Society
Email: COGeoSoc@gmail.com P.O. Box 2154, Bend, Oregon 97709
