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