EQ1 2B.2 Flashcards
(14 cards)
What is concordant coastline
Rock strata run parallel to coast
What is discordant coastline
Rock strata run perpendicular to coast
Forms headlands and bay structure
What is a bedding plane
Interface between two sedimentary strata
What are dalmation coasts
Concordant coastline
Tectonic forces caused collision of two plates creating anticlines (up folded ridge) and synclines (down folded valleys)
SLR, flooded synclines
Forms narrow islands parallel to coast
What are Haff coasts
Concordant coastline
Large bays are crossed by spits (constructive waves push ridge of sand landwards)
Creates lagoons
What are headlands and bays
Headlands - more resistant, erodes slower, protrudes
Bays - less resistant, erodes faster, indents
How do discordant coasts alter the distribution of wave energy
Cause wave refraction (waves turn and lose energy around a headland)
Wave energy focussed on headlands, forming erosional features
Energy is dissipated in bays forming beaches
What are joints
Fractures in rocks created without displacement
Igneous rock - joints form as magma loses heat
Sedimentary rock - joints form as rock subjected to compression/stretching by tectonic forces
What are faults
Major fractures in rock with displacement of rocks either side of the fault line
(created by tectonic forces)
What are folds
Bends in rocks
Sedimentary rock layers compressed by tectonic forces producing anticlines (up folded ridge) and synclines (down folded valleys)
What are dips
Angle of inclination of the rock strata from the horizontal
Sedimentary rock deposited horizontally, but can be tilted by folding/faulting by tectonic forces
What are dif types of dips and their features
Horizontal Dip:
-Vertical/near-vertical cliff
-Notches form from weathering and small mass movement
-Happens in jointed or weaker layers
Seaward Dip (High Angle, >45°):
-Gentle, sloping cliff
-Rock slides likely when top layers are weakened
-Bedding planes are weak and loosen easily
Seaward Dip (Low Angle, <45°):
-Steep or overhanging cliff
-Rock falls and cliff collapse common
-Caused by marine undercutting and overhangs
Landward Dip:
-Steep and stable cliff (70–80°)
-Gravity pulls loose blocks back into place
-Few rock falls
What is a cliff profile?
Height and angle of a cliff face, plus its features
What are microfeatures?
Small scale coastal features such as caves and wave-cut notches which form part of a cliff profile
