Geomorphology fieldtrip

Fieldtrip

Sea-to-Sky corridor

Saturday: October 28, 2017

10am – 5pm

Fieldtrip

Mountain formation, volcanoes, glacial, fluvial, and coastal processes

Nine stops:

Cypress Bowl Lookout, Porteau Cove, Stawamus Chief, Squamish Estuary, Mamquam River, Tantalus, Rubble Creek,

Brandywine Falls, Columnar Basalt

Some walking involved (down and up slopes)

Fieldtrip

Appropriate clothing for the weather; dress in layers to adjust depending on weather throughout the day

Notebook, pen/pencil, camera, hiking boots or sturdy shoes

Food and water for the day

Deglaciation of Pacific Northwest

Deglaciation of Pacific Northwest

now

10 ka

5 ka

Types of Coasts

•  Primary coasts –  Effect of ice ages

Glacial erosion Erosional processes •  abrasion

–  scouring by rock fragments embedded in the sliding (wet-based) ice –  directions of glacier

flow are reconstructed from striations

–  produces rock flour, fine sediment that becomes suspended

in glacial lakes giving them a blue-green colour

•  plucking (quarrying) –  freezing of rock

fragments to the glacier –  produces chatter

marks with removal of the fragments

Glacial landforms - Erosion Roche moutonnees

Glacial landforms - Erosion

Estuaries

•  Types of estuaries –  Processes that govern vertical mixing and stratification:

•  Strength of oscillatory tidal currents •  Rate of freshwater addition •  Bottom roughness •  Average depth

•  Circulation patterns –  Seaward at the top –  Landward at depth –  Salt and water budgets

Estuaries

•  Types of estuaries –  (A) Salt wedge, (B) well-mixed, (C) partially mixed, and (D) fjord-type estuaries

High river flow holds back lesser flow of salt water; salt water is drawn upward

Strong tidal currents distribute and mix sea-water in shallow estuary; new flow is weak and seaward at all depths

River water flows seaward over seawater;

gains salt slowly; deeper water stagnant

Seawater below mixed water which flows seaward at surface;

seaward surface net flow > than river alone A

B

C

D

Deltas Channels in deltas tend to

clog, so that new channels are created

Often more than one channel may be active at a time creating a distributary drainage pattern

Deltas

Added weight of sediment deposited in deltas leads land to slowly sink thus making more room for sediment to be deposited

Progradation leads to telltale sequence of Bottomset - Foreset - Topset beds

The Barrier

Waterfalls