Final-Coasts

Question 1

What factors shape the shore?

Answer 1

waves, tides, winds, river inputs, currents, sea level change, tectonics, volcanism, antropogenic activities

Question 2

What are the ways we classify the coast?

Answer 2

• active vs. passive (tectonics)
• primary vs. secondary (dominant influence from land or sea)
• erosional vs. depositional

Question 3

What are the differences between active and passive, primary

and secondary, erosional and depositional coasts? Where are the active and passive margins of the oceans located?

Answer 3

Passive Margin Found along coastlines where there is minimal tectonic activity

Active Margin Found on leading edge of continents where tectonic activity occurs

Primary Coast Created by non-ocean processes (volcanoes, rivers, wind), rough and irregular

Secondary Coast Created by ocean processes (waves, currents, etc)

Erosional Coasts developed by erosion due to wave action

Depositional Coasts developed by sediments accumulating from a local source (rivers)
active coastal margins (examples) pacific coastlines

passive coastal margins (examples) -atlantic coastlines

• southern ocean
• arctic ocean
• mediterranean

Question 4

What forms fjords

and where are they found?

Answer 4

fjords land erosion coastline properties:

• formed by tectonics
• scoured by glaciers
• found at high latitudes

Question 5

What are the three types of deltas and

what are examples of each?

Answer 5

types of deltas -classic delta (river dominated)

• straight coastline (wave dominated)
• Linear ridges & islands (tide dominated

ex. of classic delta Mississippi river
ex. of straight coastline delta Nile river
ex. of linear ridge & island delta Ganges-Brahmaputra

Question 6

What are drumlins and moraines?

Answer 6

drumlines & moraines - coastlines formed during glacial retreat
-formed at high latitudes

Question 7

What are the differences between barrier reefs, fringing reefs, and coral atolls? How are atolls formed?

Answer 7

fringing reef - connected to land

• typically on leeward side
• most growth at seaward side

barrier reef -separated from land by lagoon
-more growth on seaward side

Atoll -ring-shaped reef, island, or chain of island formed of coral
-formed from fringing reef (many years)

Question 8

What is the mechanism of longshore drift?

Answer 8

• from wind and refraction
• combination of longshore and onshore components
• swash and backwash translate into longshore/beach drift

Question 9

What are the principle components of a sand budget? How
do we nourish or protect beaches? What are the major dierences
between the US Atlantic, Pacic, and Gulf coasts?

Answer 9

principle components of a sand budget -inputs: longshore transport into beach, river supply, cliff erosion, onshore transport

• outputs: longshore transport out of beach, offshore transport wind transportation into dunes
• balances: depositional/steady state

beach nourishment -nearshore sand pumped onto beach
-breakwaters, jetties, groins, seawalls

Pacific coastline -active margin

• tectonics
• wave cut terrace
• narrow shelf
• beaches formed from materials transported by rivers
• minimal deltas
• uplift

Atlantic coastline -passive margin

• subsiding (except Maine)
• shoreward movement of sediment
• beaches formed from eroding shore & transport of offshore deposits
• glaciers

Gulf coast -small tidal range

• no canyons
• hurricanes
• subsidence