Geo Lab (CH. 14)

breaker zone

In the ______, wave base intersects the sea floor; here the waves lose symmetry and "break"

waves

_________ are the dominant force in shoreline erosion and deposition

embayments

coastal erosion is slowest in deep, low areas of coastal land called _________ where wave energy is diffused along a broad stretch of coastline

beaches, spits, barrier islands, salt marshes/tidal marshes

common shoreline depositional features include:

longshore drift

in areas where there is an abundant supply of unconsolidated sediment, longshore currents move sand and silt parallel to the shoreline in a process called ____________

hooks

spits that are curved sharply

salt marshes/tidal marshes

the area between a barrier island and the shoreline; formed by sediment derived from the mainland; these areas are covered with vegetation tolerant to salt water

seawalls, beach sand, groynes

3 expensive coastal management strategies: 1. building ______ to prevent wave erosion 2. renourishing eroded ________ 3. trapping sand moved by longshore drift with structures called _______

sea-level change, coastal storms, tsunamis

3 ways in which shorelines become potential natural disasters:

friction

Waves form by ____ generated when wind blows across the surface of an ocean or lake.

bench, notches

Waves move sediment back and forth across the tidal zone, abrading a flat wave-cut _____ and carving wave-cut ______

greater, smaller, lowering, raising

When an ocean widens or begins to close, the water must occupy the ______ or ______ volume of the ocean basin, _______ or _______ sea level along the ocean shoreline

shallower, break

When water is __________ than the wave base, orbiting water molecules interfere with the sea floor or lake bottom, causing waves to lose symmetry and "_____".

radius

Within a deep-ocean wave, water molecules move in a circular path. The ______ of the circle decreases with depth

tides

______ move enormous amounts of sediment all along the shoreline

emergent

______ shorelines are typically straight and bounded by steep cliffs

tsumanis

_______ are enormous waves generated by earthquakes or volcanic explosions in the ocean basins

shorelines

_______ are in a constant state of conflict between destructive wave erosion and the constructional processes of deposition, lava flows, and coral reef development

coastal erosion

_______ is most rapid in places where the land extends OUT into the ocean, because this position allows waves to attack the land from nearly every direction

Wind

_______ is not only responsible for driving waves; it also moves sediment directly in shoreline areas producing coastal sand dunes

sea arches, sea stacks

________ and ________ are distinctive, often dramatic bedrock landforms found close to the current shoreline, a short distance from the shore

tectonic activity

________ creates ocean basins, enlarges or shrinks them, and may uplift or lower the land along the coast

wind, storm surge

a common misconception about coastal storms is that _____ is the major hazard, but the _______, a wall of water driven onshore by the hurricane, is much more hazardous

wave-cut benches and wave-cut notches, sea arches and sea stacks

coastal erosion leads to 2 types of landforms to develop:

spits

elongate sand bars attached at one end to the mainland

barrier islands

elongate sand bars that lie offshore and are not connected to the mainland

submergent shorelines

if the land sinks or sea level rises, the shoreline appears to be drowned, with irregular coastline, prominent bays, and abundant islands, marshes, and lagoons

emergent shorelines

land appears to have risen from the sea by tectonic uplift or a drop in sea level

cliff retreat

sea stacks along a coastline mark the former position of the bedrock cliffs, letting us measure the amount of _______

marshy wetlands

sediment eroded from the mainland is deposited in bays between the shore and the barrier islands, forming ________

inland

shoreline cliffs gradually retreat _______

barrier islands, spits

shoreline currents redistribute sediment to produce __________, ______, and other landforms

groynes

structures that are built perpendicular to the shoreline in an attempt to trap moving sand and prevent its loss to downdrift areas

beaches

the most common depositional features and consist of sand (or coarser sediment, coral and shell fragments, etc.)

retrograde ellipse

the movement under wave bases caused by wind

breaks

the wave ______ on the shore when the ellipse can't complete its cycle once it hits land

sea stack

when further erosion removes the support for the arch, it will collapse and leave an isolated remnant of the bedrock called a _______

longshore drift

wind controls how loose materials will be moved along the shoreline in a process called ____________

sea arch

zones of weak bedrock may be eroded quickly, isolating stronger material and starting to cut into it as well. Eventually, a ________ forms

wave base

Offshore, water molecules move in circular paths, each molecule passing some energy on to those it contacts. Loss of energy in contacts limits the depth of wave action to approximately half of the wavelength, a depth referred to as the _______.

type of material present

The _______ is one of the most important factors in the effectiveness of erosional and depositional processes and therefore shoreline stability

Bay of Fundy

The ________ between the Canadian provinces Nova Scotia and New Brunswick has the highest tidal range

tides

The gravitational attraction of the Sun and Moon cause the ________: water rising and falling along the shore twice a day in most coastal areas

weather systems, strength, direction, frequency

The height and velocity of waves in a region are controlled by weather factors such as the types of ________, the _____ and _____ of winds, and the ______ of storms

material, weather, climate, climate change, tidal range, tectonic activity

The nature and rapidity of shoreline change are controlled by 4 factors: 1. _________ of which the shoreline is made 2. ________, wind, _________, and __________ 3. __________ 4. ___________

slumping, rockfall, retreats away

Eventually, the wave-cut notch undermines the cliff, causing _______ or _______, and the cliff _________ from the shoreline

long-term changes

Geologists group shorelines into 2 categories, based on how they respond to _________.

tectonic activity, climate change

long-term sea-level changes are caused by:

wave-cut bench, wave-cut notch

occurs along the shorelines; as waves drive loose sediment across shorelines underlain by bedrock, the sediment abrades a flat surface called a _________ and cuts into the base of bedrock cliffs to form a ___________

wider, landward

over long periods of time, wave-cut benches become ______ as the coastal cliffs retreat ______