Studied by 0 people
emergent landscapes are shaped significantly by falling sea levels, often linked to cooling climates. these landscapes provide valuable insight into past and present geomorphic processes.
what happened in the quaternary period?
experience glaciations/ice ages → substantial cooling of global climate
large water volumes were trapped in ice sheets/glaciers → drop in sea level. 20,000 years ago sea level was approx. 120m lower than present levels
what happens when sea levels fall?
submerged land areas are exposed → emergent landforms
primary geomorphic processes: erosion, weathering, deposition.
form raised beaches, marine terraces and abandoned cliffs
how do raised beaches form?
former shorelines are elevated above sea levels due to sea level fall + isostatic rebound
consist of wave-cut platforms and beach deposits that are located inland + higher elevation
how are marine terraces formed?
step-like landforms created by sea-level change + tectonic uplift
sea level fall, waves erode bedrock → create flat, bench-like platform. sea level stabilise temporarily, terrace is formed.
fall in sea levels/tectonic uplift → series of terraces at different elevations, each representing a former sea level.
how are abandoned cliffs formed?
steep slopes/escarpments that mark former position of the coastline
actively eroded by wave action when sea levels were higher. sea level fell → wave action shifted eastward → leaves cliffs abandoned inland
present climate change
e.g global warming → sea level rise → thermal expansion of seawater + melting of ice caps + glaciers
lead to re-submergence of emergent landforms → alters structure via wave action, erosion
future climate and sea level changes
continue sea level rise → submerge raised beaches + marine terraces → back to active coastal system
abandoned cliffs → renewed erosion is wave action reaches base → slope instability + increased landslides
ongoing tectonic acticity, isostatic adjustments + sea level change → modify emergent landscapes
Note 
Flashcard (132)