Even if the Geirangerfjord area has a geological history that stretches hundreds of millions of years back in time, it was the last ice age that formed the landscape as we see it today.
The oblique uplift of Scandinavia in the Tertiary era led to the formation of a high mountainous area parallel to the coast and sloping gently towards lower ground to the east. The uplift also rejuvenated the old, fluvial drainage systems, resulting in the formation of steep, deeply incised river valleys.
How the glaciers shaped the landscape
During the last glacial maximum about 20,000 years ago, Scandinavia was covered by a thick ice sheet. However, in the Geirangerfjord area, some of the highest mountains may have protruded as nunataks. The ice generally flowed towards the north-west with ice streams through the fjords that continued across the continental shelf onto the shelf margin.
In the Geiranger area, the glaciers eroded deeply into the bedrock, and thick till deposits accumulated only in some of the valleys oriented transverse to the main ice flow (e.g. Dyrdalen, Herdalen and Skagedalen).
When the glaciers started retreating, the fjords were first free of ice, while local glaciers remained in the mountains between the deep fjords. During the very cold younger dryas period about 12 000 years ago the glaciers were growing again, and cirque glaciers formed in the mountains and valley glaciers formed in Tafjorden and Geirangerfjorden.
Detailed maps of the fjord bathymetry reveal prominent terminal moraine ridges, which show the extent of these valley glaciers. Typical examples are the glacial deposit ridges that traverse the Norddalsfjorden from Linge, the ridges that traverse Sunnylvsfjorden and the moraine ridge at the mouth of Geirangerfjorden (see illustration on the right). There are obvious lateral moraines in the mountains and several cirque glaciers, and they can be seen on the map of surface deposits. When the main glacier melted, the melt water formed major deltas at the heads of the fjord (e.g. in Geiranger). These deltas have subsequently been expanded at increasingly lower levels as the sea level changed due to glacial isostasy and the rise of the landmass.
FjordsFjords are among the most dramatic and spectacular landscapes on Earth. They are common along the coasts of Norway, Greenland, Iceland, Alaska, British Colombia, Chile, Antarctica and New Zealand. Their typical configuration is a long, narrow and deep inlet between high mountain walls.
The scientific term fjord is used to describe a bay formed when earlier valleys became deepened and widened by glacial erosion. Fjords are restricted to coastal areas once dominated by ice sheets. The fjord is often separated from the sea by a fjord threshold, where the fjord is shallower than further in. This may be owing to moraine deposits from the glaciers remaining, or that the ice was thicker, or remained for a longer time and eroded the fjord deeper in land.
Long coastlineThe Norwegian coastline is more heavily dissected by fjords than that of any other country in the world, and appropriately the term fjord is of Norwegian origin. There are some 200 principal fjords along the mainland and 35 on the Svalbard islands. The coastline of the Norwegian fjords alone is 21,000 km long, equalling half the distance around the world at the equator. Sognefjord (200 km long and 1300 m deep), with its system of tributary fjords and fjord valleys, is clearly among the most impressive fjords on Earth. Norway occupies a latitudinal range similar to that of Greenland and the Canadian archipelago. However, the Gulf Stream conveys warm water along the entire length of the Norwegian coast, resulting in a climate not unlike the fjord coast of western North America. Environmental concerns are extremely important with respect to the Norwegian fjords, as most of the population is situated on the coast.
Geology and landforms
- How the glaciers formed the landscape
- A living landscape – The Quaternary (1.8–0 million years)
- Landslides and Avalanches
- Rivers and waterfalls
- From open ocean to narrow fjord
- A history written in stone (1600–100 million years)
- New rising – tertiary (65–2.5 million years)
- The geology of the bedrock is the key to history