Deschutes Formation Field Trip

  • 23 Jul 2023
  • 10:00 AM - 4:00 PM
  • Lake Billy Chinook Overlook
  • 0


Registration is closed


Deschutes Formation Field Trip

Led by Dr. Adam Kent

Sunday, July 23

10 AM - 4 PM

Registration Opens Friday, June 30

Please Dr. Adam Kent, of Oregon State University, for a field trip focused on the Deschutes Formation.

The Deschutes Formation (~7.5-5 Ma) represents a distinct period of explosive silicic volcanism within central Oregon. This locale is ideal for studying the processes that control silicic melt formation near the Cascade Arc, where high silica eruptive products are otherwise relatively rare. The Deschutes Formation is North America’s most recent ignimbrite flare-up, which includes ≥78 distinct explosive deposits located primarily within the modern Deschutes Basin. The  tectonic constraints controlling melt formation in the Deschutes Formation have long been an area of interest.

During this field trip we will compare the eruption histories of the Deschutes Formation and explore the regional tectonism that contributed to its development. We will visit the Deschutes Formation to observe its remarkable ignimbrite flare-up stratigraphy and discuss its possible relationship to extensional processes.

The itinerary is as follows:

10.00 Meet at Lake Billy Chinook overview (3.7 miles west of Culver OR, see directions below)
10.00 – 10.30 Deschutes Fm overview
10.45 – 11.30 Chinook Ignimbrite and righteous unconformity viewing
12.00 – 12.45 Lunch and petroglyph viewing at the “Ship”
13.00 – 14.00 Deschutes Formation basalt and sediments, pipe vesicles – short hike
14.30 – 15.30 Balanced Rock ignimbrite – short hike and optional scramble

    Click the following link for the  multi-day, 2021 GSA Field Trip Guide

Deschutes Fm Tuffs_Field Trip Guide_Pitcher, et al.pdf

The background information and stop 1.2 and portions of 2.1, 2.2 and 2.3 will be part of this one- day COGS trip

This trip is limited to 20 participants.  Some of the stops have limited parking so ride sharing is encouraged but as is COGS policy completely voluntary.  There will be a designated meet up location in Bend and perhaps Redmond. All participants must be a COGS member or a guest of one   Please leave your pets at home.

Contact the field trip coordinator, Derek Loeb ( ), with questions.  Please note I will be out of communication from approximately July 4 - July 12.

Registration must be done via the registration button on the trip listing on the COGS website.  Successful registration will be confirmed on the webpage by a light green box indicating registration was successful and by a confirmation email.  If you don't get this email you should try the registration process again.  If the trip is full, please join the wait list.


Central Oregon Geoscience Society

P.O. Box 2154,  Bend, Oregon 97709

Powered by Wild Apricot Membership Software