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Assignments due Monday

• Resume

• Top four choices of projects, in order of

preference

• One paragraph proposal about topic of choice

• Weekly schedule

• Topics you’d like to cover in class

• Math: Complete the calculus assignment

• Reading: Calculus for oceanography

• Also, start reading the Thompson (1994) paper

Resume components

• Contact information

• Objective (optional, often best not to include it)

– Not always appropriate

– Key: Modify entire resume for the position

• Education (add specific classes if appropriate)

• Awards and honors

• Employment history

• Skills and abilities

• References if appropriate

Adjust organization depending on the job you are applying for.

Shape of Puget Sound

Formation and bathymetry

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Active continental

margin of WA coast

and Cascadia

subduction zone

is complex

History of offshore tectonic plate structure debated

Recent paper (Sigloch and Mihalynuk, 2013, Nature argues that there were two

offshore plates – N and S Farallon. These plates and the Kula farther north

carried oceanic islands in offshore arcs to the West Coast, depositing terranes.

The Farallon is gone.

A tiny piece of Kula (or N.

Farallon) exists in the

Bering Sea.

Hypothesized timeline: Older view

Newer view

Salish Sea formation

• Vancouver Island

– 100 MYA Wrangellia collides with N. America

– Terrane: Oceanic Island accreted to the coast

– Now “inside passage” Vancouver Island, north

to SE Alaska

• Olympic Peninsula

– ~ 50 MYA crescent terrane collides with WA

Evolution of forearc basins and continental crust.

1: Forearc basin

oceanic arc and marginal

basin

2: Transitional forearc

3: Arc terrane accreted

onto continental crust

Sediments

Oceanic Continental

crust crust

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Resulting geology

Blakely Harbor Formation: turbidites and siltstones

Blakely Formation: sandstones

Perhaps six glaciations formed Puget Lowland

Last Four Cenozoic Glaciations:

• 1: Orting Glaciation: 1.6 – 2.4 mya

• Alderton Interglaciation

• 2: Stuck Glaciation: (no datable material)

Puyallup Interglaciation

• 3: Salmon Strings Glaciation: 1 mya

Olympia Interglaciation

• 4: Fraser Glaciation: 10,000 ~ 20,000 ya

Vashon Stade: 15,000 ya (max extent)

Heller 1980

Glacial striations (Mt. Ranier)

Ice-flow directions from erosional features and

erratics in Whatcom and Skagit Counties

Heller 1980

Observable sediments in Puget

LowlandVashon Till

Advance outwash

(Esperance Sand)

Interbedded sand and silt

Lawton Clay (proglacial lake deposits)

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Puget Lowland Deposits

Photo from Seattle Geologic Mapping Project

Stratigraphy visible from Discovery Park, Seattle

Landscape effects of glaciations

Olympics Mtns Cascade Mtns

Glacial advance outwash plain

Flutes Troughs

Landscape of Puget Lowland

Olympics Mtns Cascade Mtns

Glacial advance outwash plain

Flutes Troughs

How were the troughs cut?

Model of subglacial meltwater channel formation in Antarctica

From Le Brocq et al. 2013 Nature Geosciences

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- Glacier advance deposited

the “Great Lowland Fill”

(~ 140 m thick)

-Subglacial water eroded

the fill (about 1000 km3) to

create the linear lakes and

basins of Puget Sound

Salish Sea(Georgia Basin)

Strait of Georgia– 6800 km2, 1050 km3

– 287000 km2 watershed

– 155m avg depth

– 60-150 d residence time

Strait of Juan de Fuca– 3700 km2, 402 km3

– 500 km2 watershed

– 200 m avg depth

– 40 d residence time

Puget Sound– 2330 km2, 170 km2

– 40330 km2 watershed

– 62 m avg. depth

– 130 d residence time

Whidbey Basin

Admiralty Inlet

Main Basin

Hood Canal

South Sound

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Basins Bays and Sills (sills = glacial moraines)

• Victoria-Green Point (130 m)

• Admiralty (65,100m)

• Deception Pass (13m)

• Swinomish Slough (3m)

• Hat (Gedney) Island (97m)

• Tacoma Narrows (44m)

• Nisqually Sill (31m)

• South Point (53m)

• Oak Head (125m)

Basin character and composition

16 13 8 6

3046

2516

23

17

22 43

169

2921

15 15 16 14

area volume shoreline tideland

Admiralty Inlet

Main Basin

Whidbey Basin

South Sound

Hood Canal

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Relief track line

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Submarine relief

V-G Point Admiralty

Tacoma NarrowsNisqually Sill

Puget Sound continues to change

Major source of sediment: Rivers

• Delta alterations

• Puyallup River delta

(Commencement

Bay) not recognizable Land

Bay Glacially carved to 600 m

Filled to an avg. 200 m

Current sedimentation rate:

0.1-1.2 g/cm2/y

(~.25 – 1.5 cm/y)

Main basin

accumulating at 2x rate

of rest of PS

(89,000 yr to fill)

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