Washington

Coastal Range North Cascade Mountains Basalt lava Plateau 10,000 year old glaciated land

Rivers of Washington Excellent drainage patterns and a through-flowing river

Farm Land No tin or iron

ftg1_yakima_valley_wine_country.pdf Volcanoes in Washington

Geological Provinces of Washington Volcanic Cascade Mountains Northern Cascade Mountains Olympic Peninsula Now to the continental glacier

Wisconsin Age Glacier footprint max 17,000 years ago

Washington

High Cascades Northern Cascades Willapa Hills Puget Sound Lowland Tramping the Willapa ( WILL-ə-pah) H ills Geological Province

Cross Section: W-E Central Washington

Cross Section: W-E Central Oregon

Willapa Hills Oceanic basalt Recent Glacial sand & gravel Dry Holes 12,920’ 10,800’ Conclusions: Either a geosyncline in early stages of crushing Or an exotic terrain being welded onto Washington Detail around Castle Rock

Deep Ocean Basalt Deep Ocean Shales & Sands Recent Volcanic Basalt Recent Glacia Debris

Deep ocean shales 40 million years old Deep ocean lavas 40 million years old What rocks lie below the basalt? Eardley shows 15,000 feet of sandstones & shales foot dry hole here

High Cascades Northern Cascades Willapa Hills

40 million years old oceanic basalts Willapa Hills (north half) Area of Previous slides Area of next 5 slides

40 million years old marine sd & sh Willapa Hills (north half) 40 million years old oceanic basalts

30 million years old marine sd & sh Willapa Hills (north half) 40 million years old marine sd & sh 40 million years old oceanic basalts

40 million years old oceanic basalts 40 million years old marine sd & sh 30 million years old marine sd & sh 10 million years old marine sd & sh

40 million years old oceanic basalts 40 million years old marine sd & sh 30 million years old marine sd & sh 10 million years old marine sd & sh Willapa Hills (north half) Recent glacial debris

40 million year old oceanic crust? OR Thick 40 million year old sandstones & shales below a marine basalt lava flow? Next, a West-East Cross Section

Willapa Hills (North half) Willapa Hills (north half) Cross Section Location of a West-East Cross Section

What’s all this rock? 40 million year old oceanic crust? Thick trench (geosyncline?) filling but not under oceanic crust!!! Space Images of Willapa Hills

Space Images of Willapa Hills Focus of Basalt Areas

Washington: Topography Willapa Hills

Submarine canyons cut by glacier melt rivers Columbia River canyon Willapa Hills

Willapa Hills: Topography

Willapa Hills Next, the Columbia River

Looking East at the mouth of the Columbia River

Narrow flood plain on the Columbia

Flood plain & weather hill farming Oregon foreground, Washington across the Columbia

Willapa clearcutting

Clear-cut Logging: Willapa Hills Next: the Puget Sound Lowlands

Most Recent Continental Glaciation 100,000 to 17,000 years ago Notice that glaciers extend well out into the Pacific Ocean How did First Nation People get across Canada and into the USA and Mexico?

Flooded valley excavated by moving ice The Glacial Footprint The Glacial footprint in Washington The Puget Sound Lowlands

Olympic Peninsula Puget Sound Lowlands

High Cscades Northern Cascades Willapa Hills Puget Sound Lowlands Glacial “footprint” Lowlands and the surface rocks Olympic Peninsula Geologic Provinces of Washington

Wisconsin Age Glacier footprint max 17,000 years ago Lowlands and the surface rocks “Weak” Rocks“Strong” Rocks A Broader Picture of the Continental Glacier

Wisconsin Glaciation lasting from about 100,000 to 10,000 years ago A Broader Picture of the Continental Glacier Area of last slide These colors show the four states A Glacial Cartoon

Puget Sound Under Ice Puget Sound lowlands glacier? A Glacial Cartoon This is only the area of its footprint if the ice over Seattle was 3,412 feet deep! Here’s what the glacier really looked like

Olympic Peninsula mountains above feet What the glacier really looked like Area of a glacier 3,200 feet thick over Seattle Movement of glacial ice around the Olympic Mountains What glaciers leave behind

Glacial Erratics Glacial Striations Glacial Loess (wind blown dust) What glaciers leave behind Now the Olympic Peninsula

Olympic Peninsula The Amazing Olympic Peninsula

High Cscades Northern Cascades Willapa Hills Puget Sound Lowland Olympic Peninsula Geologic Provinces of Washington The Unique Structure of the Olympic Peninsula

The Unique Structure of the Olympic Peninsula Geologic Map Olympic Peninsula Marine basalt lava flows (folded and steeply dipping) Marine basalt lavas here are “flat lying” The Geological Unique History of the Olympic Peninsula

The Geological Unique History of the Olympic Peninsula Sands & clay debris from eroding North America Ocean water Where did the oceanic basalt and deep sea sediments come from? The Oceanic Plate Subduction Theory

The Geological Unique History of the Olympic Peninsula S l i c i n g t h e g e o s y n c l i n e Creates a landscape like Willapa Hills The Oceanic Plate Subduction Theory

The Geological Unique History of the Olympic Peninsula Compressing & folding the rocks Note: no rock melting into lavas The end result: A cartoon The Oceanic Plate Subduction Theory

The Geological Unique History of the Olympic Peninsula Plate Subduction theory: Pacific oceanic plate over ridden by the North American continental plate. Another Theory to explain the rocks of the Olympic Peninsula

Island Arc moving east North American continent moving west Exotic Terraine-Island Arc Theory 0Episode.htm

Exotic Terraine-Island Arc Theory First Island Arc welded onto North America Second Island Arc approaching North America 0Episode.htm

50 million years ago Exotic Terraine-Island Arc Theory Several Island Arcs have been welded onto North America 0Episode.htm

30 million years ago Exotic Terraine-Island Arc Theory The finale 0Episode.htm

A sketch map showing our interpretation of the original extent of the Terrane Belts extending into Washington. The southern end of the belts is covered by younger rock of the Columbia Plateau. This is our “best guess” at the original southern extent of the terranes. Exotic Terraine-Island Arc Theory The Several Accretionary Island Arcs What does the Olympic Peninsula actually look like? 0Episode.htm

Olympic Peninsula Landscapes Sedimentary sandstones and shales dipping vertically and forming rugged mountains

Mt. Carrie

Olympic Peninsula Landscapes

Olympic Peninsula Natural Resources Timber High Cascades Now, the High Cascade Mountains Note: No metals in the High Cascades Our vagabond route

Northern Cascades Willapa Hills Our vagabond route The Broader Picture of the High Cascades

The Broader Picture of the High Cascades High Cascades

map_potentially_active.html Active Volcanoes in North America

High Cascade Range Mt. Ste Helens Mt. Adams Mt Rainer

High Cascades

Mt. St. Helens Mt. Rainier Mt. Adams Mt. St. Helens

Mount St Helens Mount Adams Mt. St. Helens & Mt. Adams

Mt. St. Helens The 1980 eruption of Mount St. Helens, a stratovolcano located in Washington state, in the United States, was a major volcanic eruption. The eruption (which was a VEI 5 event) was the only significant one to occur in the contiguous 48 U.S. states since the 1915 eruption of Lassen Peak in CaliforniaMount St. HelensstratovolcanoWashington state United Statesvolcanic eruptionVEIU.S. states Lassen PeakCalifornia

9 am May Mt. St. Helens May :32 a.m. on May 18, 1980 May 19, 1982 Now the rocks of the High Cascades

Geologic Map: Washington High Cascades

Volcanic Rocks 3 million years old Geologic Map: Washington

Andesite is a gray to black volcanic rock with between about 52 and 63 weight percent\ silica (SiO2). Andesites contain crystals composed primarily of plagioclase feldspar and one or more of the minerals pyroxene and lesser amounts of hornblende Andesite magma commonly erupts from stratovolcanoes as thick lava flows, some reaching several km in length. Andesite magma can also generate strong explosive eruptions to form pyroclastic flows and surges and enormous eruption columns. Andesites erupt at temperatures between 900 and 1100° C Andesite lava: melted geosynclinal shales? lesser amounts of hornblende

High Cascades Volcanic Rocks 3 million years old Geologic Map: Washington

High Cascades Volcanic Rocks 1 million years old

High Cascades Present day active volcanoes adding more lava to the older lavas of the High Cascades Geologic Map: Washington

North America During the Last Billion Years Cretaceous Period Volcanic Rocks in the High Cascades

Cross Section: High Cascades Three Ages of Felsic* Lava Flows Where did all this molten rock come from? There must be a “furnace” melting deeply buried rock Felsic lavas: having the chemical composition of continental crust Lavas here in the Willapa Hills are Oceanic crust Oceanic crust below the “felsic” furnace!

High Cascades Northern Cascades Willapa Hills The Northern Cascades plutonic & metamorphic rocks

High Cascade Range Mt. St Helens Mt. Adams Mt Rainer Northern Cascades Washington: Topographic Map The Geologic Map: Washington

High Cascades Geologic Map: Washington Northern Cascades Area of complex *plutonic igneous & I metamorphic rocks *Plutonic: created at great depth Rocks: more of the same

Metamorphic rocks; natural ore resources Natural Resources: Washington Briefly, on the complex geology

Igneous Rocks of Northern Washington Area of complex plutonic igneous and metamorphic rocks Igneous Rocks not along the Cascade Trend

Okanogan Subcontinent

Granite Metamorphic Rocks Metamorphic Rocks Okanogan Subcontinent North American Continent Okanogan Subcontinent; age 100 million years plus or minus North American continent; age of “basement” granites & metamorphic rocks here, 2 billion years plus or minus 200 million years How do we explain the vast difference in the age of the two “basement” rock areas? First, let’s look at the “basement” rocks in the neighboring area of the North Cascade Subcontinent

North Cascade Subcontinent Area of “Basement” Plutonic Igneous and Metamorphic Rocks

Granite Metamorphic Rocks *Peridotite * Peridotite: igneous rock like Oceanic Crust Granite: igneous rock like Continental Crust Glacier Peak Major Cascade volcano last eruption 12,000 years ago Metamorphic rocks like continental crust How do we explain the vast difference in the age & rock type of these “basement” rock areas?

Okanogan Subcontinent Explaining?: the “Basement” Rock Areas of Northeastern Washington North Cascade Subcontinent North American Continent 100 million years old, mixture of igneous & metamorphic rocks of both continental and oceanic crust types 100 million years old Igneous & metamorphic rocks like continental crust 2 billion years old Continental crust of North America 1. Rocks are the deformed margin of the North American continent 2. Rocks were “rafted-in” from the west

Permian Rocks: 250 million years ago Not here But remember this one in Idaho and eastern Oregon & Washington And here

North American Continent North Cascade Subcontinent Okanogan Subcontinent 2. Rocks were “rafted-in” from the west The Generally Accepted Explanation 1. Rocks are the deformed margin of the North American continent We’ll explore explanation #1 when we’ve looked at Western Canada

High Cascades Northern Cascades Willapa Hills The Columbia Plateau plutonic & metamorphic rocks Columbia Plateau Multiple *Basalt lava flows *Basalt lava flows: similar rock to Oceanic Crust

Columbia Plateau Basalt Lava Flow Multiple lava flows About 4 million years old Similar to oceanic crust What rocks were covered by the basalt?

Rocks Thought to be Below the Basalt N o r t h A m e r i c a n C o n t i n e n t a l C r u s t 1 – 2 b i l l i o n y e a r s o l d Exotic subcontinents rafted in from the Pacific <100 million years old 4 million year old Columbia Basalt lava flows Cross Section

Northern Cascades: granite & metamorphic rocks Okanogan subcontinent Deep oceanic sediments Plateau Basalt lava flows

Rocks Thought to be Below the Basalt North American Continental Crust 1–2 billion years old Exotic subcontinents rafted in from the Pacific <100 million years old 4 million year old Columbia Basalt lava flows Cross Section

North American Continental Crust 1–2 billion years old Oldest Exotic Pacific terrane Plateau Basalt lava flows

The Source for the Lava Flows of Washington Exotic subcontinents rafted in from the Pacific <100 million years old 4 million year old Columbia Basalt lava flows Cross Section Source area for basalt lavas North American Continental Crust 1–2 billion years old

Permian Rocks: 250 million years ago Not here Source of the basalts of Oregon & Washington

North American Continental Crust 1–2 billion years old Oldest Exotic Pacific terrane Younger Exotic Pacific terranes Source of Lava Flows; SE Washington On the British Columbia

North American Continental Crust 1–2 billion years old Oldest Exotic Pacific terrane Younger Exotic Pacific terranes Source of Lava Flows; SE Washington The final geological event shaping the landscape of Washington Melting of the recent continental glacier about 10,000 years ago

Melting of the recent continental glacier about 10,000 years ago Columbia Scab Lands canyon complex carved by glacial lake melt water A more regional map

articipants/Dutch/VTrips/Scablands0.HTM Glacial Lake Spokane from the previous slide Earlier glacial Lake Missoula Canyons (scabland) created by glacial lake flood waters

Location of the Scablands

These basalt canyons provide evidence that giant floods thousands of years ago did the brunt of the work required to create this canyon.

Scablands Natural Resources: Washington

North Border of Scablands Looking North Columbia River upper background Scablands ‘”coulees” gray Farm land: flood plains

Scabland Coulee The floods left behind "coulees"—dry streambeds or gullies—all over what is now eastern Washington. Here, an old homestead sits in the bottom of a coulee within the "scablands," the term early settlers gave to the region's flood-scoured lands. Sagebrush blankets the steep, flood-cut slopes, while above them wheat fields take advantage of rich soils the floods didn't reach

Columbia River Basalt: 15 million years old present day occurrence Scablands