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2. Coastal Processes

1. Plate Tectonics and LandscapeFormation:

Building OregonCascadia Subduction ZoneColumbia Plateau Basalt

2. Ongoing Coastal Processes:Dynamic Duo: Uplift and ErosionCoastal Headlands

3. Coastal Geological Hazards:EarthquakesTsunamisLandslides

4. Interpretive Methods:Presenting Coastal Geology toCoastal Audiences

The Dynamic Landscape ofOregon’s Coast: A Tale of

Beauty and the Beast

Bob LillieProfessor of Geology

Certified Interpretive TrainerOregon State University

Oregon Coast Region of theOregon Master Naturalist Program

Unit 9: Geology of the Oregon Coast

Cape Perpetua Scenic Area, OregonFebruary 26, 2011

Mar

ine

Gar

dens

, New

port,

Ore

gon

National Park Lands inthe Coastal Ranges

CoastalRanges

Parks in the CoastalRanges contain materialsthat were manufacturedin the sea, then scrappedoff the subducting Juande Fuca Plate.

Ken

Ben

nick

Cape Perpetua Scenic Area, Oregon

The Edge of the Sea(Rachel Carson, ©1955, Houghton Mifflin Company)

“Now I hear the sea sounds about me; the night high tide isrising, swirling with a confused rush of waters against therocks below ….

Once this rocky coast beneath me was a plain of sand; thenthe sea rose and found a new shore line.

And again in some shadowy future the surf will have groundthese rocks to sand and will have returned the coast to itsearlier state.

And so in my mind's eye these coastal forms merge and blendin a shifting, kaleidoscopic pattern in which there is nofinality, no ultimate and fixed reality --

Earth becoming fluid as the sea itself.”

Joe

Gre

en

Cape Perpetua Scenic Area, Oregon

Basalt Lava Flows-Manufactured in Ocean Realm- About 35 million years ago

“……. Earth becoming fluid, as the sea itself”Rachel Carson

Deep Thought:“Speeding up the geological clock along theOregon Coast reveals Earth becoming fluid asthe sea itself.”

www.iris.edu (Animation by Jenda Johnson)

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Parks and Plates©2005 Robert J. Lillie

Layers lifted out ofthe sea, deformed,

and eroded

Ocean sand (sandstone)and mud (shale) layers

Olympic National Park, Washington

Coastal Ranges

“…. Earth becomingfluid as the sea itself.”

Ranger Jen’s OreoSubduction Demo

Coast ranges arematerial scraped off

the ocean floor.

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A grain of sand is eroded from high inthe Olympic Mountains.

National Parks reveal the recycling natureof the Earth.

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Where it’s carriedby the Hoh River.

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To the Pacific Ocean,where it’s deposited in a

layer of sand.

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Only to be uplifted and exposed again inthe Olympic Mountains.

“……. Earth becoming fluid, as the sea itself”Rachel Carson

Erosion, Subduction, and Uplift in theOlympic Mountains

Olympic - Sized RecyclingMachine!

Time: 0

Time: 5 MillionYears Parks and Plates

©2005 Robert J. Lillie

Olympic - Sized RecyclingMachine!

Time: 20 MillionYears

Olympic - Sized RecyclingMachine!

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Parks and Plates©2005 Robert J. Lillie

Olympic National Park, Washington

Volcanic rocksformed in the ocean

Coastal Ranges

Formation of Pillow Lava

The formation of pillow lava in the deep ocean has never been observed, but it probably looks a lot like this. This movie shows pillow lavaflowing underwater off the coast of Hawaii, after it was erupted on land and flowed into the ocean. Video footage from the movie "PeleMeets the Sea" courtesy of Richard Pyle (deepreef@bishopmuseum.org) at Lava Video Productions.http://oceanexplorer.noaa.gov/explorations/04fire/background/volcanism/media/pillow_lava_video.html

Mar

shak

, EAR

TH (

Nor

ton,

200

5)

Oceanic Crust

Lava Erupts into Cold Ocean Water

Formation of Pillow Lava

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Olympic National Park

Pillow Basalt

Mary’s PeakCorvallis,Oregon

Oregon StateUniversity

DowntownBeanery

CampusBeanery

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Mary’s Peak

Basalt Lava Flows- Manufactured in Ocean Realm

- About 55 million years ago

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Can we design an effective interpretativetalk on geology for the Oregon Coast?

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Seal Rock State Park, Oregon

What about these younger lava flows?Only 9 – 15 million years old

Can we design an effective interpretativetalk on geology for the Oregon Coast?“……. Earth becoming fluid, as the sea itself”

Rachel Carson

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Looking South from Cape Fowlweather, Oregon

Parks and Plates©2005 Robert J. Lillie

Plate Boundaries

YellowstoneHotspot

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John Day Fossil Beds National Monument, Oregon

Friendly park rangers engage visitors on thegeology, paleontology, and cultural history of the

John Day Country.

SheepRock

Fossil-BearingLayers

ColumbiaPlateau Basalt

Columbia Plateau –Yellowstone

Selected Parklands

Oregon StateParks

NationalPark Service

U. S. ForestService

John DayFossil Beds NM

Craters of theMoon NM

Yellowstone NP

Bureau LandManagement

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Plate moving over Hotspot

Parks and Plates©2005 Robert J. Lillie

YellowstoneHotspotTrack

NationalParklands

Yellowstone Hotspot Track

NationalParklands

Blue #’s = Age of Initial Volcanism (Million Years Ago)

Stage 1:MassiveBasalt

Stage 2:Rhyolite

17

ContinentalHotspot

Volcanism

Lava Lamp

ContinentalHotspot

Volcanism

Lava Lamp

ContinentalHotspot

Volcanism

Lava Lamp

ContinentalHotspot

Volcanism

Lava Lamp Columbia Plateau

ContinentalHotspot

Volcanism

Lava Lamp Yellowstone Supervolcano

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John Day Fossil Beds National Monument, Oregon

ColumbiaPlateauBasalt

Surfacing of Hotspot

Beauty

Picture Gorge

D. A

. Swa

nson

, U. S

. Geo

logi

cal S

urve

y

Hawai`i VolcanoesNational Park

Parks and Plates©2005 Robert J. Lillie

1969-74 Eruptionsof Mauna Ulu

The low-silica lava isso fluid that it eruptsas a “curtain of fire”through the East Rift

Zone.

Craters of the Moon NationalMonument, Idaho

Broken TopVolcano

FissureRo

bert

J. L

illie

Passed RecentlyPassed Over Hotspot

Yellowstone National Park, Wyoming

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Rhyolite Lava

On Top of Hotspot Beauty

Yellowstone National Park,Wyoming

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Old Faithful Geyser

On Top of Hotspot

TheBeast

This BBC production brought great globalawareness of Yellowstone as an active volcano

Flood Basalts and Hotspot TracksFlood Basalts and Hotspot Tracks

From Camp and Ross, JGR 2004

Plate Moves

Over Hotsp

ot

Giant Explosive Calderas

YellowstoneSupervolcano

Numbers are age of initial lava eruptionsNumbers are age of initial lava eruptions (millions of years)(millions of years)

ColumbiaPlateauBasalt

Columbia Plateau –Yellowstone

Selected Parklands

Oregon StateParks

NationalPark Service

U. S. ForestService

John DayFossil Beds NM

Craters of theMoon NM

Yellowstone NP

Silver FallsState Park

YaquinaHeadONA

Bureau LandManagement

MultnomahFalls

U. S

. For

est S

ervi

ce

Beauty

Multnomah Falls,OregonMany of Oregon’s

majestic waterfalls flowover resistant

Columbia PlateauBasalt

Columbia Gorge NationalScenic Area,

Oregon/Washington

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Silver Falls State Park,Oregon

South Falls

Many of Oregon’smajestic waterfalls flow

over resistantColumbia Plateau

Basalt

Yaquina Head Outstanding Natural Area, OregonBu

reau

of L

and

Man

agem

ent

Many of Oregon’s coastal headlands are also resistantColumbia Plateau Basalt

Can we design an effective interpretativetalk on geology for the Oregon Coast?

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Looking South from Cape Fowlweather, Oregon

Many of Oregon’s coastal headlands are also resistantColumbia Plateau Basalt

Joe

Gre

en

Cape Perpetua Scenic Area, Oregon

Basalt Lava Flows-Manufactured in Ocean Realm- About 35 million years ago

Other coastal headlands are much older basalt formed inthe ocean realm.

Can we design an effective interpretativetalk on geology for the Oregon Coast?

Orr

, Orr

, and

Bal

dwin

, “G

eolo

gy o

f Ore

gon,

” 4th

Edi

tion,

199

2

Basalt fromOcean Realm(63-29 Million

Years Ago)

Basalt from ColumbiaPlateau

(15-9 Million Years Ago)Age of

Basalt alongOregon andWashington

Coasts