1.6 - Norwegian Fjords Flashcards
Case study, Sognefjorden-Norway
- Submergent coastline as a result of eustatic SLR
- Largest Fjord system in Norway -extends 200km inland from west coast
- Alignment corresponds to fracture system in bed rock (exploited by rivers, then glaciers)
How deep are the main fjord basins
Approx. 800m below present SL
Ice age
SL during ice age is low
Eustatic change
Refers to the change in sea level
Eustatic=sea
Emergent coastlines
are commonly the result of isostatic rebound
Isostatic change
refers to change in land level.
Isostatic=land
Raised beach
A former beach now above the high tideline
-features such as round pebbles and boulders likely to be present
Submergent coastline
As a result of SLR or isostatic sinking
(e.g. UK Lands end is sinking at a rate of 1.1mm a year)
Climate change is adding 2.8 mm of SLR a year
Therefore 1.1+2.8=3.9mm of submerging rate of Land’s end
Eustatic rise since the end of the last ice age created downward landforms….
Rias,Fjords and fjard
Ria
A flooded river valley. During an ice age some land areas were not covered with ice but had frozen ground. So rivers carved valleys with steeper sides than normal. Then after the ice melted sea level rose and drowned the mouths of these valleys.
Fjord
A flooded glaciated valley. During an ice age glaciers eroded U-shaped valleys down to the coast of the time and then, after the ice had melted ,the sea level rose again and flooded into the valley over a shallow threshold ,creating a very deep water inlet with steep sides
e.g. Milford Sound in New Zealand
Fjard
Flooded inlet with low rocky banks on either side formed by post glacial drowning of glaciated lowland rocky terrain e.g. Gulf of Finland
Dalmatian coasts
Feature several linked parallel flooded valleys, with long islands between them. This isa result of submergence, when sea level rose and flooded the valleys between mountain ridges parallel to the coast
