The Landscape of Puget Sound: Tectonics and Glaciers

Courtesy Derek Booth

1) Big hole between the mountains

2) Advance outwash plain

3) TroughsHood CanalPuget SoundLk WashingtonKent Valley

4) Flutes

E-W cross-section

Puget Lowland Landscape Elements

Tectonic setting of the Puget Lowland

San Andreas fault

Subducting ofJuan de Fuca plate

Resulting N-S shortening in the Puget Lowland

Crescent Fm

Quaternary

Blakeley Fm

Blakely Harbor Fm

Eocene

Seattle basinSeattle uplift Kingston arch

km

South North

After Johnson et al., 1994

Bedrock Structure through Puget Sound

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Seattle fault zone

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Topographic expression of the Seattle fault

Bedrock highs

Scarp of Utsalady Fault – Whidbey Island

1) Big hole between the mountains

2) Advance outwash plain

3) Troughs4) Flutes5) Cross-warps

Booth, et al, 2003

K. Troost

Photographer: Roger Slatt University of OklahomaCaption: This view of the Athabasca Glacier shows depositional features as well as erosional features. The glacier is a feature of Alberta's Jasper National Park and is fed by the Columbia Ice Field.

Lateral Moraine

Terminal Moraine

Recessional Moraine

Central Whidbey Island Lidar

Outwash Channels

Kettles (holes from melted ice blocks)

Drumlins, Flutes

Double Bluff Section

Vashon till at Perkins Lane

2m

Photo by K. Troost

2) Advance outwash fill plain, Puget Lowland

Flow at snout of Nigardsbreen glacier, Norway

Water flowing into moulin

3) Troughs (subglacial channelways)—products of glacial meltwater

3) Troughs (subglacial channelways)—products of glacial meltwater

= troughs filled in bylate-recessional orpostglacial alluviumor mudflows

3) Troughs (subglacial channelways)—products of glacial meltwater

= troughs filled in bylate-recessional orpostglacial alluviumor mudflows

Gradients of subglacial water flow

1) Big hole between the mountains

2) Advance outwash plain

3) Troughs4) Flutes5) Cross-warps

4) Flutes = glacial scour

24 kmDEM from Haugerud, 2001

PresenterPresentation NotesShaded-relief image

Oblique aerial view of flutes around Echo Lake

Landscape element #5: Cross-warps

Image from Seattle-Area Geologic Mapping Project

Slide Number 1Slide Number 2Slide Number 3Slide Number 4Slide Number 5Slide Number 6Slide Number 7Scarp of Utsalady Fault – Whidbey IslandSlide Number 9Slide Number 10Slide Number 11Slide Number 12Slide Number 13Central Whidbey Island LidarDouble Bluff SectionSlide Number 16Slide Number 17Slide Number 18Slide Number 19Slide Number 20Slide Number 21Slide Number 22Slide Number 234) Flutes = �glacial scourSlide Number 25Slide Number 26Slide Number 27