coasts key idea 3b

What are submergent landscapes?

• shaped by rising sea levels → warming climate

What happened during the Holocene period?

• began ~11,700 years ago → earth clinate warmed after last glacial period

• warm temp → ice sheets + glaciers melt → rise in global sea levels

• sea level rose 120m from lowest point

what are rias?

• estuarine drowned river valleys formed by sea level rise → flood river valleys that were excavated by rivers

how are rias formed?

• as sea levels rise, river valleys flooded → deep, branching estuaries with irregular shorelines + steep sides

what are fjords?

• glacially-carved submerged valleys → deepened + widened by advancing glaciers during past ice ages

how are fjords formed?

• glaciers melted + retreated due to warm climates → u-shaped valleys submerged by rising sea levels → create deep, narrow inlets with steep cliff sides

what are shingle beaches?

• beaches composed of coarse, rounded pebbles and cobbles

how are shingle beaches formed?

• rising sea levels + coastal erosion transport + deposit large sediments → create distinct beaches that reflect current dynamic coastal processes

how does present climate change modify these landforms?

• accelerated sea level rise, mainly due to thermal seawater expansion + melting of ice caps + glaciers

• sea level rise → increase coastal erosion → alter stability of submerging landforms

how does future climate change modify these landforms?

• sea level rise → flood coastal areas → submerge low-lying coastal plains

• rias + fjords → change in sedimentation patterns + erosion rates → affect ecological + geomorphic characteristics

• shingle beach → shift/disappear as sea level rises → impact coastal protection + biodiversity