Title: Chapter 2: The Geomorphology of Eroding and Accreting Coasts
1Chapter 2 The Geomorphology of Eroding and
Accreting Coasts
Examples Continental Margins Tectonic
Classification of Coasts Tectonic effects on
coastal sediment supply
2Example Coastlines Morphology
3Terminal Moraine Long Island
4Transgressive Regressive Sequences
5(No Transcript)
6Natural vs Engineered Barrier Island Profiles
Data Westhampton Beach
7Sources of Sand For Littoral Transport
Bluff Erosion Offshore Glacially Deposited Sand
Ridges, Relict Ebb Shoals
Cliff or Bluff Coast
Tide Dominated Riverine
Gravel
2 m
Wave Dominated
Sand
Mixed Energy
Barrier Island
8(No Transcript)
9(No Transcript)
10(No Transcript)
11(No Transcript)
12(No Transcript)
13Spit Accretion Theory
14Spit Accretion Fire Island Inlet
15- Littoral Transport reaches a maximum rate of
463,015 to 601,657 yd3/yr at Democrat Point (Fire
Island Inlet)
16(No Transcript)
17Continental Margins
18Continental Shelves broad shallow extension of
the continents (75km wide) Regions of deposition
(rivers, glaciers, scrapped marine deposits,
calcium carbonate) Large bedform features,
reworked by tides, storms, waves
19Continental Slopes continental crust thins into
oceanic crust steep (20km, 1-25 degrees), 5deg
Pacific, 3deg Atlantic extend to depths between
1500-4000 m
20Continental Rise Fan like deposit where the
continental slope intersects the abyssal
plains Formed by turbidity currents
21Tectonic Evolution of Continental Margins
Atlantic Margin passive margin, edge of the
continent is in the middle of a lithospheric
plate, little seismic activity, no
volcanism Pacific Margin active margin, edge of
the continent coincides with a plate boundary,
rim of the Pacific Ocean, ring of fire, seismic
activity and volcanism
22Tectonic Coastline Classification (Inman
Nordstrom)
- Tectonic Setting (Pacific-vs-Atlantic type
margin) - Tectonic Setting of opposite side of the
continent - Geologic Age of the coast
- Exposure to open ocean conditions
- Collision Coasts
- Continental collision coasts
- Island arc collision coasts
- Trailing Edge Coasts
- Neo-trailing edge coasts
- Afro-trailing edge coasts
- Amero-trailing edgo coasts
- Marginal Sea Coasts
23Continental collision coasts continental
oceanic plate boundary narrow margin, deep
trench seismic activity, coast backed by high
mountains
24Island Arc collision coasts oceanic oceanic
plate boundary narrow margin, deep
trench moderate mountain ranges Ex Japan,
Philippines, Aleutian Islands
25Neo-Trailing Edge Coasts Atlantic type
margins geologically young Ex Red Sea, Gulf of
Aden, Gulf of California
26East African Rift System
27Afro-Trailing Edge Coasts both sides of the
continent are passive margins lack organized
drainage pattern Ex Africa, Greenland
28Amero-Trailing Edge Coasts opposite side of the
continent is an active margin organized drainage
pattern Ex Atlantic coast of NS America and
Europe, India
29Marginal Sea Coasts direct exposure to the ocean
is reduced due to island arc system Ex Gulf of
Mexico, Bearing Sea, Sea of Japan, East and South
China Seas
30Classification Based on Tidal Range
Microtidal lt 2 m Mesotidal 2 4
m Macrotidal gt 2 m
31Classification Based on Wave Energy
Walton and Adams, 1978
32Hydrodynamic Coastline Classification
Tide Dominated Wave Dominated Mixed Energy
(Hayes, 1975)
33Long Island Classification
Amero-Trailing Edge Coast South Shore Significant
Wave Conditions H 1.5 m, T 8
sec Micro-Tidal Environments
Cliff or Bluff Coast
Tide Dominated
Tide Dominated Riverine
Gravel, sand
Gravel
2 m
Wave Dominated
Sand
Mixed Energy
Barrier Island