1Image courtesy National Park ServiceDeschutes Land Trust 2014

Crooked River Caldera,

a Super Volcano

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Geology and Landforms of Central Oregon

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Empire State is 1, 250 ft. tall.

= 4.5 Billion Years

Last 60 Million Years

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GEOLOGY OF THE NORTH HALF OF THE LOWER CROOKED BASIN, CROOK,

DESCHUTES, JEFFERSON, AND WHEELER COUNTIES, OREGON.

Jason D. McClaughry1, Mark L. Ferns1, and Caroline L. Gordon2

1. Oregon Department of Geology and Mineral Industries, Baker City Field Office, 1510 Campbell Street, Baker City, OR 97814

2. United States Forest Service, Ochoco National Forest and Crooked River National Grassland, 3160 NE 3rd St., Prineville, OR 97754

Funded in part by the USGS under the National Cooperative Geologic Mapping program under assistance awards 05HQAG0037 and 06HQAG0027

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E. L. Orr and W. N. Orr, “Geology of Oregon,” Kendall/Hunt Pub. Co., 5th Edition, 1992.

Geologic/Physiographic Provinces of Oregon

Making Connections:

• Oregon’s ecology is closely tied to Oregon’s geology.

Ecoregions of Oregon

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High Cascades

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Blue Mountains

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Columbia Plateau

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Basin and Range

10Parks and Plates

©2005 Robert J. Lillie

Most of Oregon and Washington has

been added to the edge of the

continent in the past 150 million

yearsMaterial added since then by

Subduction and Terrane Accretion

Coastline 150 Million Years Ago

11http://cpgeosystems.com/paleomaps.html

Opening of the

Atlantic ocean

150Million Years

Ago

Jurassic

Ron BlakeyNorthern Arizona

University

12http://cpgeosystems.com/paleomaps.html

140Million Years

Ago

Cretaceous

Ron BlakeyNorthern Arizona

University

13http://cpgeosystems.com/paleomaps.html

130Million Years

Ago

Cretaceous

Ron BlakeyNorthern Arizona

University

14http://cpgeosystems.com/paleomaps.html

115Million

Years Ago

Cretaceous

Ron BlakeyNorthern Arizona

University

15

http://cpgeosystems.com/paleomaps.html

50Million

Years Ago

Eocene

Ron BlakeyNorthern Arizona

University

16

http://cpgeosystems.com/paleomaps.html

40Million Years

Ago

Eocene

Ron BlakeyNorthern Arizona

University

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Geologic History - Tectonic Setting

Faults!!!

John Day River

Deschutes River

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Lithology Map (Rocks!!)

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150-60 Million Years ago …

Ammonites

Warm Tropical Seas!!

Geologic History

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Geologic map of the north half of the Lower Crooked Basin

Prineville

Wildcat Mtn.

Crooked River

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Formation of a

caldera

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Clarno Formation ~44 to 39 Ma

Clarno Formation - Eocene Epoch44-39 Million Years ago

Wildcat Mountain

Brennon Palisades

Tropical Climate

First of 2 Major Volcanic Episodes

Ocean Front Property

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Steins Pillar

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Geologic map: Wildcat Mountain Caldera ~40 Ma

Steins Pillar tuff

Andesite &Dacite porphyry43.8 Ma

Hash Rock rhyolite39.4 Ma

Andesite41.5 Ma

Hwy 26

Mill Creek

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Wildcat Mountain caldera

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Rhyolite intrusions within the Wildcat Mountain caldera

Twin Pillars

Forked Horn Butte

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Wildcat Mountain caldera

Steins Pillar Tuff

Crooked River caldera- Tuff of Smith Rock– Monkey Face

John Day

Clarno

Clarno

John Day

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John Day Formation ~36 to 25 Ma

Ochoco Reservoir

Prineville Res.

Lk. Billy Chinook

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John Day Formation - Oligocene Epoch 36-25 Million Years ago

Big Summit Prairie

Temperate Climate

2nd Major Volcanic Episode

Coastline on the Eastern Edge of the Willamette Valley

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2 mm

Gray Butte

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Mahogany Mountain caldera - Leslie Gulch tuff 15 Ma

Crooked River caldera - Smith Rock tuff 29.5 Ma

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Crooked River Caldera -29.5 Ma

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Looking across the Caldera!

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Rhyolite intrusions

Tuff of

Smith Rock Rhyolite

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Hydrothermal deposits

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Modern examples from the Yellowstone caldera

41Yellowstone Caldera

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http://cpgeosystems.com/paleomaps.html

25Million Years

Ago

Oligocene

Ron BlakeyNorthern Arizona

University

43

http://cpgeosystems.com/paleomaps.html

15Million Years

Ago

Miocene

Ron BlakeyNorthern Arizona

University

44

Miocene Epoch25-16 Million Years ago

Mt. Pisgah

N. Fork Crooked River

Semi-arid Climate Emerging

Thick Columbia River Basalt flows pouring out across the NW

Picture Gorge Basalt Source near Monument

45http://cpgeosystems.com/paleomaps.html

8Million Years

Ago

Miocene

Ron BlakeyNorthern Arizona

University

46http://cpgeosystems.com/paleomaps.html

3Million Years

Ago

Pliocene

Ron BlakeyNorthern Arizona

University

47

Neogene Rocks ~16 to 3 Ma

Includes: Prineville basalt, Simtustus Fm., Deschutes Fm.

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Deschutes Formation (~9 to 3 Ma)

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The Geologic map for Prineville

Ochoco Viewpoint

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The geologic landscape at Prineville:

Basalt of Stearns Ranch3-4 Ma

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Quaternary ~1.8 Ma to present

Includes: basalt from Newberry volcano and

Alluvium

Ochoco Reservoir

Lake Billy Chinook

Smith Rock St. Park

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Large Volcanoes Erupting – Pleistocene Epoch1.8 Million Years to 11,700 years

Mt. Hood

Mt. Jefferson

Mt. Mazama

Inter-canyon Flow Basalts

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Smith Rock State Park

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http://cpgeosystems.com/paleomaps.html

Laurentide glaciation

12,500Years Ago

Holocene

Ron BlakeyNorthern Arizona

University

55http://cpgeosystems.com/paleomaps.html

Present Day

Now

Ron BlakeyNorthern Arizona

University

56

Holocene Epoch11,700 years to Present

Habitat for Wildlife and PlantsMt. Mazama Ash = Soil Additive

Mt. St. Helens Ash Fall

Mt. Mazama

Geologic map of the west part of the Lower Crooked Basin

A A’

Rin

g-fractu

re

Clarno Fm.

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The Calderas are

The Resource

*Crooked River CalderaPrineville

Wildcat Caldera

Smith Rock

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Oregon’s Super Caldera

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Geologic Foundation

Our Volcanic Past has brought us a wonderfully complex environment!

We’re at the apex of 4 physiographic provinces.

We live with Geology

Geologic history that includes Major Volcanic Episodes

The Calderas – Wildcat Mountain and Crooked River

Smith Rock/Gray Butte Grizzly Butte Powell Butte

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