Classification:
Barrier Island & Sea-cliff
Shoreline Features:
Depositional
spit
tombolo
baymouth bar
barrier island
tidal delta
ebb
flood
dune
berm
Erosional
Wave cut cliff
wave cut platform
sea-arch
sea-stack
headland
notch
Shoreline Processes:
Wind
•Daily: Waves Tides
•Annual: large storms (hurricane) rise & fall of sea level
•Long Term (1000 yr) uplift & subsidence of land
Daily Processes:
Waves of Oscillation vs Waves of Translation
wind velocity - Wave height depends on wind duration
fetch
Longshore Drift = Beach Drift + Longshore Current
Wave retraction around headlands.
Tides: centrifugal forces + gravitational forces
- spring tides vs Neap tides
- effect of resonance
- storm surges
Sea-level rise: melting of ice + expansion of sea water near surface.
Coastal uplift vs subsidence
- effects on Maine's coastline
- emergent vs submergent coastlines
Quaternary history of Maine's coastline
Review Questions
1. Identify and briefly discuss two long-term processes which are affecting Maine's coastline. How is the present shoreline responding to these two processes?
2. Use a completely labeled diagram to assist you in explaining how longshore drift transports sand along a coastline.
3. Use a labeled diagram to assist you in explaining how wave refraction affects headland areas along a coast.
4. Use a diagram to assist you in explaining how and why structures such as jetties, groins and breakwaters interfere with normal beach processes.
5. Explain how sea waves form and how they evolve as they encounter shallow water along a coastline. Include a labeled cross-section to illustrate your discussion.
6. Identify the three distinct time scales over which coastal processes operate. Discuss the coastal processes that operate on each time scale.
7. Draw a map or plan view of a coastline containing the following features: headland, baymouth bar, salt marsh, pocket beach, spit and tombolo.
8. Use a labeled diagram to illustrate the difference between spring tides and neap tides.
9. Identify 2 features which would help you to distinguish between a coastline which is being submerged from one which is emerging. Briefly explain why some coasts are submergent while others are emergent.
10. Briefly explain how a seawall ultimately results in the destruction of beach.
11. Briefly discuss the geological events which have shaped Maine's
coastline over the past 20,000 years.