Tides, geology and ocean currents influencing coasts Flashcards
(13 cards)
What are the physical factors influencing coastal landscape systems?
Tides, geology, global pattern of ocean currents
These factors interact to shape coastal environments.
Define tides.
Cyclical and predictable rise and fall in the level of the sea
Tidal patterns are influenced by the gravitational pull of the moon and sun.
What is a spring tide?
An extreme tidal range due to combined gravitational pull of the moon and sun
Spring tides occur when the sun and moon are aligned.
What is a neap tide?
A small tidal range caused by opposing gravitational pulls of the moon and sun
Neap tides occur when the sun and moon are at right angles.
What does lithology describe?
The composition of rock and its resistance to weathering and erosion
Different types of rocks have varying levels of resistance.
What type of rock is sedimentary?
Created by consolidation of sediment layers under heat and pressure
Examples include sandstone and limestone, which are porous and less resistant to erosion.
What are igneous rocks formed from?
Formed under extreme heat and pressure, increasing resistance to erosion
Examples include granite and basalt.
What is the geological structure?
Includes fractures such as joints, folds, and faults influencing erosion rates
Geological structure affects how landscapes respond to erosive forces.
Define ‘dip’ in geology.
The angle of the rock strata created by tectonic movement
It can be vertical, seaward dip, or landward dipping.
What happens when a wave propagates towards the shore?
Waves become swell waves and then translatory waves as they break
Translatory waves transfer energy and water onto the shore.
What drives surface ocean currents?
Mainly by wind and weather patterns
Surface currents are also influenced by gravitational tides.
What causes deep ocean currents?
Changes in water density due to temperature and salinity differences
Colder, more saline water at the poles is denser and leads to downwelling.
True or False: Surface currents have a greater impact on the present coastal zone than deep ocean currents.
True
Deep ocean currents contribute to longer-term geological changes.
