Geological structure Flashcards
What is geological structure?
Defined as the arrangements of rocks in layers, or folds and the joints and bedding planes within them.
What is lithology?
Rock types and their general characteristics
What are bedding planes?
Horizontal breaks in the strata, caused by gaps in time during periods of rock formation.
What is a dip?
The angle at which the rock strata lie. Can be horizontal, vertical, towards the sea or inland.
What are faults?
Formed when the stress or pressure to which a rock is subjected exceeds its internal strength causing it to fracture.
What are folds?
Formed by pressure during tectonic activity, which makes rock buckle and crumple.
What is strata
Layers of rock.
What is a ‘lulworth crumple’?
A huge fold in the strata caused by tectonic activity
How do headland and bays form?
Form on discordant coasts where waves erode softer rocks faster than harder rocks.
Hard rock forms the rocky headlands that stick out into the sea.
How do coves form?
CONCORDANT COASTS
Waves start to exploit weaknesses such as faults or large joints.
At Man O’ War Cove, waves have broken through the relatively resistant wall of Portland limestone and have eroded a cove in the less resistant Wealden shales.
Why marine processes gradually smooth out headlands and bays.
The indented shape of the coastline causes waves to refract (bend) as they approach the headlands, and this concentrates the energy of waves on them, increasing rate of erosion and creating caves, stacks and stumps. Waves slow down on entering bays and so lose energy, depositing bay-head beaches.
