Monthly Presentations

The Central Oregon Geoscience Society holds regularly scheduled monthly presentations on the 4th Tuesday of each month, from September to November, and from January to May. All presentations are free and open to the public.


Please join us at Bridge 99 Brewery:

63063 Layton Avenue, Bend

5:30 pm social hour

7:00 pm presentation


Please join us for the social hour before the presentation -- all are welcome! 

Presentations are also live-streamed through Zoom. Please see the presentation details for Zoom registration links. Zoom presentations are recorded whenever possible, please see the list of past presentations to watch recordings of past talks.

Visiting Scholar Presentations

Visiting Scholar presentations are scheduled during various times outside the regular monthly meeting schedule. Please check the schedule below for updates, or join the COGS email list for updates. To join the email list, go to the Join us page.



Upcoming Presentations

    • 27 Feb 2024
    • 5:30 PM
    • Online and in-person at Bridge 99 Brewery

    Dana Johnston

    University of Oregon









    click HERE to register for Zoom


    5:30 pm social hour

    7:00 pm presentation


    A common misconception is that magmatism within our planet results from a thermal anomaly of some sort, causing a local perturbation in the geotherm. While this is sometimes the case, the vast majority of magmatic activity in fact results from decompression of hot rocks or lowering their solidus temperature through the introduction of fluxing agents, principally H2O. The former dominates at mid-ocean ridges, oceanic and continental hot spots and continental rifts while the latter dominates at subduction zones. Much of our knowledge of these processes derives from experimental petrologic studies at elevated pressures and I will show how such investigations shed light on these mechanisms through which our planet differentiates.


    Please join us at Bridge 99 Brewery:

    63063 Layton Avenue, Bend

    5:30 pm social hour

    7:00 pm presentation

    COGS talk are free and open to the public -- all are welcome! Please join us for the social hour before the presentation.

    All presentations are also live-streamed through Zoom. There will be a registration link at the top of this page as we get closer to the date of this presentation.

    • 26 Mar 2024
    • 5:30 PM
    • Online and in-person at Bridge 99 Brewery

    Mike Darin

    Oregon Department of Geology and Mineral Industries



    5:30 pm social hour

    7:00 pm presentation


    Society’s focus on renewable energy sources and electric vehicles has created a surge in demand for lithium, which plays a vital role in supporting the transition to a low-carbon transportation infrastructure and mitigating the impacts of climate change. McDermitt caldera straddles the SE Oregon-Navada border and hosts the largest known lithium resource on Earth. In this talk, we’ll discuss the geology of McDermitt caldera, how lithium deposits form in general, and the recent surge in federal funding for critical mineral research.


    Please join us at Bridge 99 Brewery:

    63063 Layton Avenue, Bend

    5:30 pm social hour

    7:00 pm presentation

    COGS talk are free and open to the public -- all are welcome! Please join us for the social hour before the presentation.

    All presentations are also live-streamed through Zoom. There will be a registration link at the top of this page as we get closer to the date of this presentation.

    • 23 Apr 2024
    • 5:30 PM
    • Online and in-person at Bridge 99 Brewery

    Joan Fryxell

    California State University, San Bernardino






    5:30 pm social hour

    7:00 pm presentation




    Please join us at Bridge 99 Brewery:

    63063 Layton Avenue, Bend

    5:30 pm social hour

    7:00 pm presentation

    COGS talk are free and open to the public -- all are welcome! Please join us for the social hour before the presentation.

    All presentations are also live-streamed through Zoom. There will be a registration link at the top of this page as we get closer to the date of this presentation.

    • 28 May 2024
    • 5:30 PM
    • Online and in-person at Bridge 99 Brewery

    Anders Carlson

    Oregon Glaciers Institute










    5:30 pm social hour

    7:00 pm presentation


    During the last ice age an ice cap covered much of the Oregon Cascade crest, with a north-south length roughly between that of the modern Northern and Southern Patagonia ice caps. Oregon’s ice cap stands out from other late Pleistocene ice bodies in the western United States in that its deglacial history is largely unknown. Here, we will present new Helium-3 surface exposure ages for the ice cap collected from the Three Fingered Jack and Middle Sister regions. These ages will directly date when it retreated from its last glacial maximum extent and then paused to deposit moraines close to late Holocene/historical moraines. This new chronology will allow us to relate ice-cap change to regional climate change as recorded in marine and cave temperature records. We will also have new Helium-3 ages for potential prehistoric late-Holocene moraines just outboard of historic moraines from Hayden Glacier on Middle Sister and Eliot Glacier on Mount Hood. In sum, these new ages will expand the record of cryospheric change in Oregon from less than the last 150 years, to likely more than the last 20,000 years.




    Please join us at Bridge 99 Brewery:

    63063 Layton Avenue, Bend

    5:30 pm social hour

    7:00 pm presentation

    COGS talk are free and open to the public -- all are welcome! Please join us for the social hour before the presentation.

    All presentations are also live-streamed through Zoom. There will be a registration link at the top of this page as we get closer to the date of this presentation.

    • 24 Sep 2024
    • 5:30 PM
    • Online and in-person at Bridge 99 Brewery

    Diego Melgar

    University of Oregon










    5:30 pm social hour

    7:00 pm presentation


    In this presentation we’ll explore a major question about the 1700 Cascadia earthquake: Was it one big earthquake, or a series of smaller ones happening close together in time? Understanding this is crucial for forecasting future earthquakes and tsunamis in the Cascadia region. Here we’ll use computer models to examine the different possibilities, using extensive historical earthquake data to rule specific scenarios as likely or not. In the end, we’ll conclude that we can't be certain if the 1700 earthquake was a single event and that the possibility that it was a sequence of earthquakes needs to be considered as equally likely.


    Please join us at Bridge 99 Brewery:

    63063 Layton Avenue, Bend

    5:30 pm social hour

    7:00 pm presentation

    COGS talk are free and open to the public -- all are welcome! Please join us for the social hour before the presentation.

    All presentations are also live-streamed through Zoom. There will be a registration link at the top of this page as we get closer to the date of this presentation.

Past Presentations

23 Jan 2024 Onset and impacts of the c.7700 ybp eruption of Mount Mazama, Oregon
28 Nov 2023 Hydrology of High-Desert Springs in Eastern Oregon
24 Oct 2023 Sunstones: The Good, The Bad, & The Ugly (in other words, the complex petrogenesis of our state gemstone)
26 Sep 2023 Live Tour of the JOIDES Resolution
23 May 2023 Looking down to look ahead: How Oregon’s fossil rodents can help us understand the impacts of past and future climate change
25 Apr 2023 In the Shadow of Volcanoes
28 Mar 2023 The Most Recent Earthquake on the Mount Hood Fault Zone, Oregon: Implications for cascading earthquake, landslide, & flood multi-hazards in the Columbia River Gorge
28 Feb 2023 Ancient Soils of Earth and Mars
24 Jan 2023 The ancient magnetic field: Clues hidden in lava flows from around the world
22 Nov 2022 The development of the science of geology and the growth of the railroad industry: How geology played a significant role in railroads of the Pacific Northwest
25 Oct 2022 The Rock Bottom of Antarctica’s Food Chain
27 Sep 2022 Paleoseismic investigations of Quaternary active faults in the forearc and backarc of the central Pacific Northwest
22 Sep 2022 Evidence of humans in North America during the Last Glacial Maximum
28 Jun 2022 Volcanoes! Travelogue and Science of Two Volcanic Arcs
24 May 2022 Encountering the Unexpected in Pacific Northwest Geology
26 Apr 2022 When Magmas Meet High-Tech Metals: What Can the Mountain Pass Rare Earth Element Deposit Bring to the Future?
22 Mar 2022 Newberry Volcano Geothermal Projects, Past and Future
22 Feb 2022 From maar craters to cinder cones: Understanding Oregon's small, but most common, volcanoes
25 Jan 2022 Wildfire and Debris Flows
23 Nov 2021 Tectonic evolution of the Cascadia margin in southwest Oregon during the past 55 million years
26 Oct 2021 Evaluation of slip history and Holocene activity on faults in the Strawberry Mountains
28 Sep 2021 Timing and controls on growth of the Oregon Basin and Range Province
25 May 2021 I Date Rocks: A Geochronology Love Story
27 Apr 2021 Water in the Deschutes Basin: 2020 Hindsight – What Happened?
23 Mar 2021 The fragmented death of the Farallon Plate
23 Feb 2021 Our Vanishing Glaciers, Part II
26 Jan 2021 The Next Great Cascadia Earthquake - How did we get here?
24 Nov 2020 What lies under recently active Cascades volcanoes?
27 Oct 2020 Mapping the Magmatic Pathways Beneath Volcanoes from Newberry, Oregon to Santorini, Greece
22 Sep 2020 Red Rocks from Earth to Mars
25 Jun 2020 Extinction: Using catastrophic events to construct the geologic timeline
26 May 2020 The history and science of glacier change in the western US and a peek into their future
28 Apr 2020 Volcanoes in Our Backyard: Understanding and Mitigating Volcano Hazards in Central Oregon
24 Mar 2020 I Date Rocks: A Geochronology Love Story
25 Feb 2020 Mountains, Earthquakes, and Landslides: Using Lasers to Peer Behind Cascadia's Green Veil
28 Jan 2020 Three Newly Discovered Fault Systems in Oregon
26 Nov 2019 Oregon's Checkered Past
22 Oct 2019 The Other Flood: Ice-age Bonneville Flood on the Snake River
24 Sep 2019 Tectonic History of the Coos Bay Basin and its Relationship to Pacific Northwest ‘Siletzia’ Tectonics
10 Aug 2019 Newberry Volcano: A sleeping giant with two bubbling lakes
28 May 2019 Holocene Glacial and Paleoclimate Reconstructions in the North Cascades, Washington
23 Apr 2019 A new look at “old” tuffs from Newberry Volcano: Evidence for dynamic magmatic processes at a geologic crossroads in central Oregon
26 Mar 2019 Kīlauea's 2018 Fissure Eruption – Chronology, Processes, and Impacts of Kilauea's Largest Eruption in 200 Years
26 Feb 2019 Mountains, Earthquakes, and Landslides: Using Lasers to Peer Behind Cascadia's Green Veil
22 Jan 2019 The High Lava Plains of Oregon: Volcanic and Tectonic Connection between Yellowstone and the Cascades
27 Nov 2018 Groundwater hydrology and groundwater-dependent ecosystems of central Oregon
23 Oct 2018 The Crooked River Caldera
25 Sep 2018 Assembling the Northwest: A roadside view of Oregon and Washington geology
16 Jul 2018 Oregon's volcanoes: What have we learned from global advances in volcanology over the past decade?
22 May 2018 Oblique subduction, rotating crustal blocks, and the active tectonics of the Pacific Northwest
24 Apr 2018 Mount Hood: Confessions of an interesting Boring volcano
27 Mar 2018 Geothermal Exploration at Newberry Volcano

Central Oregon Geoscience Society

Email: COGeoSoc@gmail.com
P.O. Box 2154,  Bend, Oregon 97709

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