Geological structure and the development of coastal landscapes Revision Notes for Edexcel A-Level Geography

Geological structure and the development of coastal landscapes

Strata → 🔗 The different layers of rock within an area and how they relate to each other
Deformation → 🔗 The regress to which rocks have been deformed by tectonic activity
Faulting → 🔗 The presence of major fractures that have moved rocks from their original positions Results in the following types of coastlines being formed:

Concordant → Rock strata running parallel to the coastline (eg. The Dalmatian Coast in the Adriatic Sea)

Haff coastlines
Long sediment ridges topped by sand dunes run parallel to the coast just offshore
Lagoons (haffs) are created between the ridges and the shoreline

Discordant → Alternating bands of hard and soft rock at right angles to the coastline

Less resistant rocks are eroded to form bays, whereas more resistant rocks remain as headlands
Headlands are eroded more than bays because…
In deep water, crests are parallel
As water shallows towards the coast, waves slow down & wave height increases ↑
In bays, wave crests curve to reflect their shape and wave height decreases ↓
Wave action is concentrated on headlands

Influenced by…

The resistance of the rock to erosion
The dip of the rock strata
Faulting → Major fractures in rocks produced by tectonic forces and involving the displacement of rocks on either side of the fault line
Natural cracks - jointing and fissures → joints occur in most rocks, dividing the rock strata up into blocks with a regular Fissures often only occur a few cm/mm long ↳ The location of micro features within cells, such as caves, are often controlled by the location of faults and/or strata which have a particular high density of joints & fissures