Coastal Landscapes Flashcards
Ria
Drowned river valleys. Floodplains of the river may be completely drowned, leaving higher land exposed, forming many offshore islands. They consist of long, narrow and sheltered winding inlets with irregular shorelines. The deepest water is at the mouth (depth of water increases as you move seaward). They are common in south-west England, e.g. the Kingsbridge estuary in Devon.
Submergent Coast
Stretches along the coast that have been inundated by the sea due to a relative rise in sea level (either isostatic or eustatic). They are the opposite of emergent coastlines.
Raised Beach
It is an emergent feature, formed due to the result of isostatic recovery where former shoreline platforms or beaches were raised above present sea level. They are common on the west coast of Scotland, where the remains of previously eroded cliff lines with wave-cut notches, caves, arches, and stacks can be found.
Fjord
Drowned glacial valleys. They are straight and narrow with steep valley sides, a typically U-shaped cross section with hanging valleys on either side. They are not deepest at the mouth but consist of a shallower section at the end (a threshold) which was created due to reduced glacial erosion as the thinner ice met the sea (marking where the glacier left the valley) Found in New Zealand, Norway and Chile.
Fjard
An inlet formed by the marine submergence of formerly glaciated valleys and depressions within a rocky glaciated terrain of low relief. They are characterised by a profile that is shorter, shallower, and broader than the profile of a fjord.
Emergent Coast
Stretches along the coast which have experienced a rise in the land surface or a fall in sea level. They are the opposite of submergent coastlines and may have several landforms: e.g. raised beaches or wave cut platforms.
Concordant coastline
Runs parallel to the coastline and has the same type of rock running along the coastline. The outer hard rock (for example, granite) provides a protective barrier to erosion of the softer rocks (for example, clays) further inland.
Discordant coastline
Bands of different rock type run perpendicular to the coast. The differing resistance to erosion leads to the formation of headlands and bays.
Haff coast
Consists of concordant features. A long shallow lagoon parallel to the shore, separated from the open sea by a narrow parallel sandbar/barrier beach.
Dalmatian coast
A concordant coast formed due to a rise in sea level. Valleys and ridges run parallel to each other, and when the valleys are flooded, the tops of ridges remain above the surface of the sea as a series of offshore islands that run parallel to the coast.
Geological structure (bedding planes / joints)
Physical characteristics of rocks: strata (layers of rock); bedding planes (horizontal cracks/natural breaks in strata caused by gaps in time during periods of rock formation); joints (vertical cracks caused by either contraction as sediments dry out or by earth movements during uplift); folds (formed by pressure during tectonic activity which makes rocks buckle and crumple); faults (formed when stress subjected on a rock exceeds its internal strength causing it to fracture) and dip (refers to angle at which rock strata lie).
High Energy Coastline
Wave power is strong for a greater part of the year. The rate of erosion exceeds the rate of deposition. Coastlines are rocky and consist of erosional landforms; such as caves, arches, stacks, and stumps. E.g. Cornwall
Low-energy environment
Wave power is lower for most of the year as the heights are lower and waves spread outwards, dissipating energy. The rate of deposition exceeds the rate of erosion. Commonly estuarine and sandy coastlines, consisting of depositional landforms; such as sand dunes. E.g. Bamburgh
Till
Also known as boulder clay, it is unsorted material deposited directly by glacial ice.
Fossil Cliff
Coastal exposure of the remains or impression of a prehistoric plant or animal embedded in rock
