coastal, beaches, estuaries

Question 1

explain what coasts are

Answer 1

where land meets the sea
Area affected by marine processes
- tides, wind, waves, storm surges
➢ Dynamic places of constant change
- deposition and erosion of sediments

Question 2

what are some examples of coasts

Answer 2

cliffs dunes, beaches, bays, coves and river deltas

Question 3

what is a primary coast

Answer 3

where coasts are shaped by processes on land, sediment erosion or deposition by rivers wind and ice.

Question 4

what are the two main causes of primary coasts?

Answer 4

VOLCANIC ACTIVITY: Hawaii lava builds up, the tectonic plates move, and repeats this series repeats (left most island =oldest right most island=youngest)

SEISMIC ACTIVITY: San Francisco Bay or Tomales Bay; where tectonic movement causes a faulting and displacement of the earths crust.

another example: drowned river valley

Question 5

what is a secondary coast

Answer 5

Where the ocean changes the coast

-waves, tides, current
- Alterations by marine plants

Question 6

what’s an example of secondary coasts

Answer 6

-White cliffs of dover. Made of foraminifera shells. The cliff was once under water but sea level fell and the cliff was eroded by waves.

-Sea Stacks by wave erosion

-Barrier Islands- a sediment source is carved out and deposited else where .

-Mangroves, salt marshes- coastal vegetation- very productive areas - formed by intrusion of sea water.

Question 7

what is a delta ?

Answer 7

deposit of river-borne sediment left at a river mouth
- produces a flat and fertile coastal area

Question 8

what are the shapes and structures of beaches?

Answer 8

wide or narrow
steep or flat
long or pocket

Question 9

what sources create beaches ?

Answer 9

land materials brought by rivers or derived
from local cliffs by wave erosion
- shell, coral, minerals, rock particles, and lava

Question 10

what kind of beach has high energy and why

steep or flat

Answer 10

STEEP!

Question 11

what kind of beach has higher energy and why?

[sand+mud ]or [pebble cobble and boulder ]

Answer 11

PEBBLE COBBLE AND BOULDER. found close to their source, too
large to be moved any distance

Question 12

why are sand an bus beaches lower energy ?

Answer 12

eroded materials, small particles easily
transported or redistributed by waves and currents

Question 13

High energy beaches have ___ sand and low energy beaches have ____ sand

Answer 13

coarser: finer

Question 14

color of beach sand is an indicator of :

Answer 14

what minerals the sand is made out of.

Question 15

is beach sand in constant motion ?

Answer 15

yes

Question 16

there is dynamic equilibrium between supply, transport and removal of sediment. what are the two beach dynamics we learned in class?

Answer 16

alongshore transport and split formation.

Question 17

explain alongshore transport.

Answer 17

Alongshore transport moves sediment along the coast in a zigzag pattern due to angled wave action.

waves approach, gravity pull them down, water moves, repeat

Question 18

explain split formation.

Answer 18

occurs when sediment transported by alongshore currents is deposited in an area where wave energy decreases, extending the shoreline out into the water.

Question 19

what are estuaries

Answer 19

where the river meets the ocean

Question 20

if a split formation closes what do we cal this

Answer 20

a coastal lagoon

Question 21

if a split formation reaches out to an island we call this a

Answer 21

tombolo

Question 22

what are some for characteristics of an estuary

Answer 22

Sources of buoyant water plumes
*heavily populated
* Are habitats for a large number of
organisms
* Formed as a result of sea level rise
* Very young (10,000 years) in
geological terms
* Have global significance due to their
capacity to exchange water and
sediment with the ocean

Question 23

classification of estuaries by tide :

Answer 23

microtidal <2m
* mesotidal 2-4 m
* macrotidal 4-6 m
* hypertidal >6

Question 24

classification of estuary by topography

Answer 24

Drowned river valleys (Coastal
Plain Estuaries)
* Formed by rising sea level
* Fjords
* Formed by retreating
glaciers

Question 25

classification of estuary by salinity

Answer 25

highly stratified
* salt wedge estuary
– well mixed estuary
– partially mixed estuary

Question 26

explain the characteristic of a salt wedge estuary

Answer 26

High river discharge
* Weak tidal currents
* Strong stratification
* Weak mixing

Question 27

explain characteristics of a well mixed estuary

Answer 27

Low river discharge
* Strong tidal currents
* Weak stratification
* Strong mixing

Question 28

explain the characteristics of a partially mixed estuary

Answer 28

Mixture of salt-wedge and well-mixed
* Most prevalent estuary

Question 29

what are some key characteristics of river deltas

Answer 29

Extensive agricultural
development
* Highly populated

1) High sediment load
2) Low energy waves and currents at the river mouth