1. What is Newberry Volcano?
View of Newberry Volcano from the northeast.
Julie Donnelly-Nolan, USGS Menlo Park CA,
Tim Grove, MIT, & Rick Carlson, Carnegie Institution
View of Newberry edifice from the northeast

2. Cascades or not? High Lava Plains volcano?
view south of the Newberry edifice from Bend, Oregon
Cascades or not? High Lava Plains volcano?
Is it a volcanic field, not a volcano?

3. Cascades arc
not equal to
Cascade Range

4. Newberry Volcano Sited at the Intersection of the Cascades and the High Lava Plains Magmatic Province
Colored Regions Show Volcanic Deposits Younger than 17 Million Years (Smith and Luedke, 1984)
South Sister, Oregon
Cascades
Diamond Craters
Newberry

5. Newberry margin
Three
Sisters
Newberry edifice

6. Newberry lavas
cover ~3000 km2
For comparison,
MSH

7. 10 m DEM
Focused on
Newberry Caldera

8. At least 3 calderas, 300 ka - 80 ka
view from Paulina Peak
At least 3 calderas, 300 ka - 80 ka

9. Highest point on caldera rim is Paulina Peak at nearly 8000 ft.,
~4000 ft. higher
than surrounding
terrain
View of Paulina Peak from Paulina Lake

10. Newberry Volcano
Medicine Lake volcano
Slide courtesy of Mike Poland

11. Newberry Volcano
Medicine Lake volcano

12. Geologic Map of Newberry Volcano By MacLeod, Sherrod,
Chitwood, & Jensen
Qba
~35 mapped Newberry
units
Scanned map courtesy of
Templeton, Taylor, Giles,
& Rowe (WOU, OSU)

13. Field challenges --
field assistant
& Mazama
& lots of similar rocks

14. The Subduction Contribution
Sr = 1124 ppm
Just to show what type of normalized incompatible element patterns go with the extremes of major element composition.
~4% H2O
Sr = 300 ppm
87Sr/86Sr =
187Os/188Os =
87Sr/86Sr =
187Os/188Os =
(Carlson data)

15. (Carlson isotope data)15

16. What is the “Subduction Component”?
Just to make the point that the sediment component has 87Sr/86Sr of about Can’t have a big component of old sediment.
(Carlson data) 16

17. He isotope data
Graham, et al.
JVGR 2009

18. NV
Grove et al. model

19. WVF
Figure adapted from B. Jordan PhD thesis

20. Newberry rhyolites are lower in SiO2
than HLP rhyolites

21. Newberry Volcano A subduction-related volcano, not an HLP volcano
Calc-alkaline basalts as well as HAOT-type basalts
Is isotopically like Cascades lavas
Lies behind the arc axis = rear-arc volcano
Extensional terrain; strong magmatic focus
Edifice with central caldera eruptions; not a volcanic field

22. Tectonic setting Of Newberry: interaction of tectonism and volcanism a
key feature
Mt. Jefferson
WVF
High Lava Plains
Crater Lake

23. Interpretation: Fore-arc, arc axis, & rear-arc volcanoes
Behind-the-arc Quaternary
volcanism
From Donnelly-Nolan et al., JVGR 2008

24. Preliminary version of Newberry geologic mapping will be on
display Monday at poster booth 288
View of Newberry edifice from the southeast
Acknowledgments: with thanks to Robert Jensen, Dave Ramsey, Duane Champion,
Andy Calvert, Marvin Lanphere, Larry Chitwood