Landforms and Surficial Deposits

Surficial deposits, the layers of rock sediments that drape over the bedrock, are not only valuable natural resources, they also contain a wealth of geological information. The processes involved in the formation of these deposits have contributed to the development of the spectacular and dramatic landscape of Norway.
Fjords and valleys - Norway's most spectacular landforms? The trough show here was formed by glacial erosion that took place during several ice ages, and attests to the transforming power the deep rivers of ice that flowed through the landscape.

The presence of surficial deposits and the distinctive land forms in Norway are closely related to the glacial history in the Quaternary era (last ca. 2.6 million years) and especially to our last ice age, the Weichselian (ca 117 000-11 700 years ago). Glacial erosion during this last and previous ice ages have carved out valleys, formed unique landscape features and left behind huge amounts of loose broken-down rock fragments.  The glacial tracks and rock deposits are examined to help geologists interpret Norway's geological history and to understand the processes that have contributed to the landscape development.

Breelvavsetning bestående av sand og grus. Slike løsmasser utgjør god byggegrunn, er svært viktige råmaterialer i en rekke sammenhenger og gode reservoarer for grunnvann. Fra Vinstra i Gudbrandsdalen. Foto: Fredrik Høgaas.
Glacifluvial deposits composed of sand and gravel. Such materials serve as a good base for construction projects, can be used as a raw material in a variety of contexts, and are often good reservoirs for ground water. From Vinstra in Gudbrandsdalen. Photo: Fredrik Høgaas.

Detailed information about the Norway's surficial deposits is also important from a societal perspective. Thorough mapping can provide comprehensive information about the types of raw materials and natural resources that are available, as well as providing information useful to those involved in construction, waste storage, uncovering resources, identifying potential natural hazards, sources of groundwater etc.

The glaciers eroded, shaped and deposited

Surficial Deposits are mapped according to dominant geological processes occurring during deposition. In Norway, most soil types are either directly or indirectly related to the movement of ice sheets, such as till or glacifluvial material, or as sediments that were washed out by the glaciers into the sea. Deposits that occur independent of glaciations may include, for example, block fields, landslide masses and river and beach deposits. These are often indirectly affected by what was left behind after a glacial period.

Rogenmorener øst for Hestkjølen i Nord-Trøndelag. Slike landformer finnes ofte i nedsenkninger av terrenget og er orientert på tvers av den tidligere isbevegelsesretningen. Foto: Harald Sveian.
Rogen moraines east of Hestkjølen in Nord-Trøndelag. These land forms are often in the lower terrains and lying transverse to earlier ice flow direction.  Photo: Harald Sveian.

Landforms and terrain elements 

The time required for landform formation, its dimensions and the processes involved can widely vary.  Some formations may have been formed during a single episode, such as a landslide scar or glacial striations. However, recurrent processes taking place over several glacial and inter-glacial periods, have formed Norway's fjords, valleys and alpine landscapes. Terrains can be shaped erosion, and the reworking of the bedrock or sediments of the older landscape, or the deposition of landforms.

Landforms are created by a variety of geological processes.  Ice sheets are a major transforming element, as evident from the elongated drumlins of moraine material that have deposited under ice.  More often, however, glacial streams deposited and eroded material below, next to and in front of the glaciers, such as eskers, and marginal channel. Large deltas or submarine fan deposits form where the glacial streams reach a body of water (lake or sea). 

Landformer på liten og stor skala, både temporalt og romlig. To kryssende skuringsstriper kan ses ved kompasset, mens bakgrunnen domineres av egger og tinder som er gravd ut og skulptert av botnbreer over en lang tidsskala. Fra Handnesøya i Nordland. Foto: Fredrik Høgaas.
Landforms Handnesøya in Nordland, at a large and small scale, defined spatially and temporally.  Here, in the foreground by the compass we see two intersecting glacial striations whereas arête and tinds (glacial horns) in the background are evidence of the movement of Cirque Glaciers (Alpine Glaciers). Photo: Fredrik Høgaas

Marine processes have washed, sorted and redistributed rock material ever since the glaciers began their retreat inland. This retreat resulted in the creation of a number of land formations as the continental surface lifted. One of the land formations are ridges, consisting of shoreline material, thrown far up on the continent by powerful storm waves. Isostatic uplift has also uncovered the former seabed, where landslide processes have formed the shards in the terrain in the form of mudslide. There are also many other processes that form the terrain elements. The diversity of geological processes, and the interaction between them, is reflected in an even greater diversity of landforms, which helps us solve the geological puzzle.