Denudation chronology

Denudation chronology is the study of the long-term evolution of topography seen as sequence. Denudation chronology revolves around episodes of landscape-wide erosion, bettern known as denudation. The cycle of erosion model is a common approach used to establish denudation chronologies.[1]

References

  1. ^ Jones, David K.C. (2004). "Cycle of erosion". In Goudie, A.S. (ed.). Encyclopedia of Geomorphology. pp. 244–248.
Baltic Shield

The Baltic Shield (or Fennoscandian Shield) is a segment of the Earth's crust belonging to the East European Craton, representing a large part of Fennoscandia, northwestern Russia and the northern Baltic Sea. It is composed mostly of Archean and Proterozoic gneisses and greenstone which have undergone numerous deformations through tectonic activity. It contains the oldest rocks of the European continent with a thickness of 250-300 km.

The Baltic Shield is divided into five provinces: the Svecofennian and Sveconorwegian (or Southwestern gneiss) provinces in Fennoscandia, and the Karelian, Belomorian and Kola provinces in Russia. The latter three are divided further into several blocks and complexes and contain the oldest of the rocks, at 2500-3100 Ma (million years) old. The youngest rocks belong to the Sveconorwegian province, at 900-1700 Ma old.

Thought to be formerly part of an ancient continent, the Baltic Shield grew in size through collisions with neighbouring crustal fragments. The mountains created by this tectonic processes have since been eroded to their bases, the region being largely flat today. Through five successive Pleistocene glaciations and subsequent retreats, the Baltic Shield has been scoured clean of its overlying sediments, leaving expansive areas (most within Scandinavia) exposed. It is therefore of importance to geophysicists studying the geologic history and dynamics of eastern Europe.

The scouring and compression of the Baltic Shield by glacial movements created the area's many lakes and streams, the land retaining only a thin layer of sandy sediment collected in depressions and eskers. Most soil consists of moraine, a grayish yellow mixture of sand and rocks, with a thin layer of humus on top. Vast forests, featuring almost exclusively the three species pine, spruce and birch, dominate the landscape, clearly demarcating its boundaries. The soil is acidic and has next to no carbonates such as limestone. The scouring by the ancient glaciers and the acidity of the soil have destroyed all palaentologically interesting materials, such as fossils.

The Baltic Shield yields important industrial minerals and ores, such as those of iron, nickel, copper and platinum group metals. Because of its similarity to the Canadian Shield and cratons of southern Africa and Western Australia, the Baltic Shield had long been a suspected source of diamonds and gold. Currently, especially the Central Lapland Greenstone Belt in the north is considered to be an unexplored area that has the potential to hold exploitable gold deposits.

Recent exploration has revealed a significant number of diamond-bearing kimberlites in the Kola Peninsula, and (possibly extensive) deposits of gold in Finland.

Bohuslän

Bohuslän (Swedish pronunciation: [²buːhʉːsˌlɛːn] (listen); Danish/Norwegian: Båhuslen) is a Swedish province in Götaland, on the northernmost part of the country's west coast. It is bordered by Dalsland to the northeast, Västergötland to the southeast, the Skagerrak arm of the North Sea to the west, and the county of Østfold, in Norway, to the north.

Bohuslän is named after the medieval Norwegian castle of Bohus. Under the name Baahuslen, it was a Norwegian county from the Norwegian conquest of the region from the Geats and subsequent unification of the country in the 870s until the Treaty of Roskilde in 1658, when the union of Denmark-Norway was forced to cede this county, as well as Skåneland (part of Denmark proper) to Sweden.

As of 31 December 2016, the number of inhabitants was 299,087, giving a population density of 68 inhabitants per square kilometre (180/sq mi).

Cycle of erosion

The geographic cycle or cycle of erosion is an idealized model that explains the development of relief in landscapes. The model starts with the erosion that follows uplift of land above a base level and ends – if conditions allow – in the formation of a peneplain. Landscapes that show evidence of more than one cycle of erosion are termed "polycyclical". The cycle of erosion and some of its associated concepts have, despite popularity, been a subject of much criticism.

David Linton (geographer)

Professor David Leslie Linton (12 July 1906 – 11 April 1971), British geographer and geomorphologist, was professor of geography at Sheffield and Birmingham, best remembered for his work on the landscape development of south-east England with S. W. Wooldridge, and on the development of tors.

Finke River

The Finke River, or Larapinta (Arrernte), is a river in central Australia, one of four main rivers of the Lake Eyre Basin and thought to be the oldest riverbed in the world. It flows for only a few days a year and when this happens, its water usually disappears into the sands of the Simpson Desert, rarely if ever reaching Lake Eyre.

Geomorphology

Geomorphology (from Ancient Greek: γῆ, gê, "earth"; μορφή, morphḗ, "form"; and λόγος, lógos, "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or near the Earth's surface. Geomorphologists seek to understand why landscapes look the way they do, to understand landform history and dynamics and to predict changes through a combination of field observations, physical experiments and numerical modeling. Geomorphologists work within disciplines such as physical geography, geology, geodesy, engineering geology, archaeology, climatology and geotechnical engineering. This broad base of interests contributes to many research styles and interests within the field.

List of important publications in geology

This is a list of important publications in geology, organized by field.

Some reasons why a particular publication might be regarded as important:

Topic creator – A publication that created a new topic

Breakthrough – A publication that changed scientific knowledge significantly

Influence – A publication which has significantly influenced the world or has had a massive impact on the teaching of geology.Compilations of important publications can be found in Further reading.

Paleic surface

The paleic surface or palaeic surface (Norwegian: paleiske overflaten, from Ancient Greek palaios, meaning 'old') is an erosion surface of gentle slopes that exist in South Norway. Parts of it are a continuation of the Sub-Cambrian peneplain and Muddus Plains found further east or equivalent to the strandflat coastal plains of Norway. Hardangervidda, a particularly flat and elevated part of the Paleic surface formed in the Miocene at sea level.Although the tilted plateau-like topography of south Norway had been noted since the early 1800's, the first formal description was by Hans Reusch in 1901, using a denudation chronology approach invoking several of W.M. Davis’ ideas of a cycle of erosion. Reusch also coined the name Paleic surface.The Paleic surface is sometimes erroneously considered equal to Norway's "pre-glacial surface" – the surface that existed in Norway just before the Quaternary glaciations.

Pediment (geology)

A pediment is a very gently sloping (.5°-7°) inclined bedrock surface. It typically slopes down from the base of a steeper retreating desert cliff, or escarpment, but may continue to exist after the mountain has eroded away. It is caused by erosion. It develops when sheets of running water (laminar sheet flows) wash over it in intense rainfall events. It may be thinly covered with fluvial gravel that has washed over it from the foot of mountains produced by cliff retreat erosion. It is typically a concave surface gently sloping away from mountainous desert areas.It is not to be confused with merged groups of alluvial fans (bajadas), which also may appear to gently slope from an escarpment, but are composed of material eroded from canyons, not bedrock.Three formational zones are recognized for pediments:

An inner most zone of mountainous uplands that have near vertical erosion

An intermediate zone or degradation zone which is the pediment beyond the mountain front.

An outer zone or aggradation zone which extends beyond the pediment and is a zone of deposition.Coalescence of pediments over a large area results in a pediplain.

Pediplain

In geology and geomorphology a pediplain (from the Latin pes, genitive case pedis, meaning "foot") is an extensive plain formed by the coalescence of pediments. The processes through which pediplains forms is known as pediplanation. The concepts of pediplain and pediplanation were first developed by geologist Lester Charles King in his 1942 book South African Scenery. The concept gained notoriety as it was juxtaposed to peneplanation.The coalesced pediments of the pediplains may form a series of very gentle concave slopes. Pediplains main difference to W. M. Davis’ peneplains is in the history and processes behind, and less so in the final shape. Perhaps the most notable difference in form that may be present is that of residual hills which in Davis’ peneplains are to have gentle slopes while in pediplains they ought to have the same steepness as the slopes in the early stages of erosion leading to pediplanation.Pediplanation is linked to scarp retreat in the following way: as scarps retreat over geological time pediments migrate and extend over large areas. The result is that the surface is eroded chiefly backward and that downward erosion is limited. In contrast to common peneplain conceptualizations several pediplains might form simultaneously at different altitudes and do not necessarily grade to a base level. Pediplains are normally formed in areas of arid and semi-arid climate. As climate changes arid and semi-arid periods of pediplanation may alternate with more humid periods of etchplanation resulting in the formation of flattish surfaces (peneplains) of mixed origin (polygenetic).Cryoplanation is a variant of pediplanation that is restricted to cold climates.

Plain

In geography, a plain is a flat, sweeping landmass that generally does not change much in elevation. Plains occur as lowlands along the bottoms of valleys or on the doorsteps of mountains, as coastal plains, and as plateaus or uplands.In a valley, a plain is enclosed on two sides, but in other cases a plain may be delineated by a complete or partial ring of hills, by mountains, or by cliffs. Where a geological region contains more than one plain, they may be connected by a pass (sometimes termed a gap). Coastal plains would mostly rise from sea level until they run into elevated features such as mountains or plateaus.Plains are one of the major landforms on earth, where they are present on all continents, and would cover more than one-third of the world's land area. Plains may have been formed from flowing lava, deposited by water, ice, wind, or formed by erosion by these agents from hills and mountains. Plains would generally be under the grassland (temperate or subtropical), steppe (semi-arid), savannah (tropical) or tundra (polar) biomes. In a few instances, deserts and rainforests can also be plains.Plains in many areas are important for agriculture because where the soils were deposited as sediments they may be deep and fertile, and the flatness facilitates mechanization of crop production; or because they support grasslands which provide good grazing for livestock.

Sten Rudberg

Sten Rudberg (13 September 1917 – 22 October 1996) was a Swedish geologist and geomorphologist. He was the son of Gunnar Rudberg. Sten Rudberg was appointed chair professor of the Göteborg University in 1958 after incumbent professor Karl-Erik Bergsten moved to Lund University. In 1959 Rudberg was elected into the Royal Society of Sciences and Letters in Gothenburg. Subsequently in 1961 Rudberg's professorship was transformed into a professorship in Physical geography. In 1964 Rudberg went to head the department of Physical geography after the Geography department of the Göteborg University was dissolved and Human geography formed its own department. Rudberg remained professor in Gothenburg until 1984.Rudbergs Ph.D. thesis dealt with the large-scale geomorphology and denudation chronology of Västerbotten in northern Sweden, he subsequently continued to work on large scale geomorphology of Scandinavia while also making scientific contributions dealing with wind erosion, cliff retreat, and periglacial mass movements. While working with large-scale geomorphology Rudberg was not concerned with tectonics.

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