landforms and landscapes of deposition - barrier beach/bars Flashcards
when do barrier beaches occur?
when a beach or spit extends across a bay to join to headlands
what do barrier beaches trap?
water forming a brackish lagoon which is sepretated from the sea
what can they form from?
contemporary processes or due to rising sea levels after the last glacial period - glaciers deposident sediment in the coastal zone
when does barrier beach become a barrier island?
if it is speerted from the mainland
what kind of areas are barrier beaches common in?
low tidal ranges
what is a tombolo?
bar or beach that connects the mainland to an offshore island
why are tombolos formed?
due to wave refraction off the coastal island reduce wave velocity
what is an offshore region?
where sand is deposited - as waves dont have enough energy to carry sediment to shore - they absorb wave energy
what provides an important sediment input into coastal zone (offshore bars)?
waves may pick up sediment from an offshore bar
when else are offshore bars formed?
when backwash removes sediment from a beach?
