Paper 1 Flashcards
1) Explain the contribution of erosional processes in producing sediment (6 marks)
Abrasion: Waves pick up sediment and stones, acting as abrasives to wear away at cliffs. This constant wearing down detaches particles, gradually breaking down rock into smaller fragments, contributing to sediment formation.
Hydraulic Action: Waves exert pressure, forcing air into cracks and joints in rock. Over time, this weakens the rock’s integrity, widening joints and fractures, making it more susceptible to erosion and facilitating sediment production.
Corrosion: Weak acids in seawater dissolve rock minerals, releasing fine-grained particles into the water. This chemical weathering alters rock composition, adding to sediment load, particularly in coastal areas with high salinity.
Attrition: Rocks collide during water transport, reducing size and rounding edges. Continuous collision wears down sharp edges, producing smoother, rounder sediment particles, enhancing transportability by water currents.
2) Explain the role of geology in the formation of contrasting cliff profiles (8 marks)
Rock Type: Granite and limestone, being resistant, form steep cliffs, while clay and shale, less resistant, create gentle slopes.
Structural Features: Folded or faulted rocks introduce variations in erosion susceptibility, influencing cliff profiles and adding complexity to coastal landscapes.
1) Explain the role of sea level change in the formation of both emergent and submergent coastlines (8 marks)
Emergent Coastlines: Shaped by relative sea level fall during glacial periods, exposing previously submerged areas and revealing unique features like raised beaches and marine terraces.
Submergent Coastlines: Result from relative sea level rise during interglacial periods, leading to the encroachment of seawater and the submersion of low-lying coastal areas.
2) Explain the differences in the characteristics of beaches over time, such as between summer and winter (6 marks)
Summer Beach Characteristics:
Warmer weather and reduced wave energy lead to finer sediment accumulation, creating expansive sandy shores.
Increased recreational activities during summer can redistribute sand, shaping the beach profile.
Summer promotes beach vegetation growth, stabilizing sand and preventing erosion.
Winter Beach Features:
Higher wave energy during winter, driven by storms, causes enhanced erosion and sand removal from beaches.
Winter storms deposit coarser sediments, reshaping the beach profile with steeper slopes and narrower beach areas.
Winter storms may remove or disturb beach vegetation, affecting stabilization efforts.
Explain the causes of sea level change and the formation of resultant coastal landforms
1) Glacial Cycles: Glacial periods- decrease in sea level=eustatic change –> marine terrace Interglacial periods- rise in sea level–> raised beaches
2) Thermal Expansion– Rise in sea levels– eustatic–> raised beaches
3) Tectonic movements can uplift or subside coastal areas, impacting sea levels.
Tectonic activity creates geological features like fault lines and volcanic islands, shaping coastlines.
Explain how geological structures such as strata, joints, and folds influence the formation of coastal landforms
Strata (Layering):
Layers of rock varying in composition, hardness, and erosion resistance.
Differential erosion occurs, forming cliffs from harder layers and embayments from softer layers.
Example: Sedimentary coastal cliffs undergo erosion, creating sea caves, arches, and stacks from alternating hard and soft rock layers.
Joints:
Fractures in rock from stress or tectonic forces.
Water infiltration and freeze-thaw cycles widen joints, leading to mechanical weathering.
Erosion along joints forms sea cliffs, with water seepage causing rock detachment.
Example: Jointed coastal cliffs, like basalt or granite formations, may form sea stacks and caves aligned with joints.
Folds:
Bends in rock layers from tectonic compression.
Fold orientation shapes coastal features, affecting ridges, valleys, and offshore structures.
Erosion along fold axes or limbs sculpts coastal landscapes.
Example: Folded rock layers along the Dalmatian coast accentuate ridge structures, creating island chains parallel to the coastline.
Discuss the significance of dip angle in determining the stability and erosion rates of coastal cliffs.
Gentle dip: More stable, reduced risk of mass wasting events like rockfalls or landslides.
Gentle dip: Slower erosion due to reduced exposure to wave energy.
Steep dip: Less stable, higher risk of mass wasting events such as rockfalls or landslides.
Steep dip: Faster erosion as waves more effectively undercut the base.
Describe how lithology influences the formation of coastal cliff profiles.
Rock Resistance: Different rock types vary in their resistance to erosion. Harder rocks, such as granite or basalt, are more resistant and tend to form vertical cliffs, while softer rocks, like sandstone or clay, erode more easily, leading to gentler slopes or terraces.
Jointing and Bedding: The presence of joints and bedding planes in rock layers can affect the stability and shape of coastal cliffs. Rocks with well-developed joint systems may experience more rapid erosion along these planes, leading to the formation of vertical faces or overhangs.
Stratification: Layered rock formations, or strata, influence the morphology of coastal cliffs. Alternating layers of hard and soft rock can create stepped or terraced profiles, where erosion-resistant layers form prominent ledges or platforms.
Explain the role of hydraulic action and abrasion in shaping coastal cliffs
Hydraulic Action:
Hydraulic action occurs when the force of water against the cliff face dislodges and removes rock particles through pressure and impact.
Waves, particularly during storm events, exert tremendous hydraulic pressure on coastal cliffs, forcing water into cracks and joints and causing rock fragments to break off.
The repeated pounding of waves against the cliff face weakens the rock structure and contributes to the formation of sea caves, notches, and other erosional features.
Abrasion:
Abrasion involves the wearing down of the cliff face by the impact of sediment particles carried by waves.
As waves crash against the cliff, they carry sand, pebbles, and other sediment that act as abrasive agents, scouring and grinding away at the rock surface.
Over time, the constant abrasion by wave-borne sediment smoothens and shapes the cliff face, forming distinctive features such as wave-cut platforms and cliff notches.
Sand Dune Succession
Begins with pioneer species like lyme grass stabilizing embryonic dunes.
Progresses through stages: embryo dunes, fore dunes, yellow dunes, grey dunes, and mature dunes.
Each stage is characterized by different plant species and increasing stability.
Salt marsh succession
Starts with pioneer species like algae and salt-tolerant grasses colonizing bare sediment.
Develops into diverse ecosystems with increasing vegetation cover.
Influenced by factors such as sediment deposition, tidal fluctuations, and plant interactions.
How does vegetation stabilize coastlines
Binding soil/sand with roots, reducing erosion impact.
Reducing wind speeds, which decreases erosion and promotes deposition.
Adding organic matter from dead plant material, leading to soil formation.
Spits
Definition: Extended stretches of sand or shingle that extend out to sea from the shore.
Formation: Result from longshore drift transporting sediment along the beach, often culminating in a curved end or hook.
Example: Spurn Head in Yorkshire, England.
Tombolos
Definition: Landforms formed when a spit joins the mainland to an island.
Formation: Occurs due to sediment accumulation connecting the mainland and an island, often creating a narrow strip of land.
Example: Chesil Beach in Dorset, England, connecting the Isle of Portland to the mainland.
Bars
Definition: Raised ridges of sediment away from the shore.
Formation: Develop where sediment levels are high and the sea is shallow, often formed offshore.
Example: The Outer Banks of North Carolina, USA.
