HOME

TheInfoList



OR:

The Glarus thrust (german: Glarner Überschiebung) is a major
thrust fault A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Thrust geometry and nomenclature Reverse faults A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. If ...
in the
Alps The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, Sw ...
of eastern
Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...
. Along the thrust the
Helvetic nappes {{Unreferenced, date=June 2019, bot=noref (GreenC bot) The Helvetic nappes (german: Helvetische Decken) are a series of nappes in the Northern part of the Alps and part of the Helvetic zone. They consist of Mesozoic limestones, shales and marls tha ...
were thrust more than 100 km to the north over the external
Aarmassif The Aarmassif or Aaremassif (German: ''Aarmassiv'') is a geologic massif in the Swiss Alps. It contains a number of large mountain chains and parts of mountain chains. Name The massif is named after the Aar, a river that has its source in the A ...
and Infrahelvetic complex. The thrust forms the contact between older (Helvetic) Permo-
Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest per ...
rock layers of the Verrucano group and younger (external)
Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...
and
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...
limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms w ...
s and
Paleogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( Mya) to the beginning o ...
flysch Flysch () is a sequence of sedimentary rock layers that progress from deep-water and turbidity flow deposits to shallow-water shales and sandstones. It is deposited when a deep basin forms rapidly on the continental side of a mountain building epi ...
and
molasse __NOTOC__ The term "molasse" () refers to sandstones, shales and conglomerates that form as terrestrial or shallow marine deposits in front of rising mountain chains. The molasse deposits accumulate in a foreland basin, especially on top of flysc ...
. The Glarus thrust crops out over a relatively large area in the cantons
Glarus , neighboring_municipalities= Glarus Nord, Glarus Süd, Muotathal (SZ), Innerthal (SZ) , twintowns= Wiesbaden-Biebrich (Germany) } Glarus (; gsw, Glaris; french: Glaris; it, Glarona; rm, Glaruna) is the capital of the canton of Glarus ...
, St. Gallen and Graubünden, due to its horizontal orientation and the high local
relief Relief is a sculptural method in which the sculpted pieces are bonded to a solid background of the same material. The term '' relief'' is from the Latin verb ''relevo'', to raise. To create a sculpture in relief is to give the impression that th ...
. Famous outcrops include those at Lochsite near
Glarus , neighboring_municipalities= Glarus Nord, Glarus Süd, Muotathal (SZ), Innerthal (SZ) , twintowns= Wiesbaden-Biebrich (Germany) } Glarus (; gsw, Glaris; french: Glaris; it, Glarona; rm, Glaruna) is the capital of the canton of Glarus ...
(the town) and in a mountain cliff called ''
Tschingelhörner The Tschingelhörner (also spelled ''Tschingelhoren'') are a chain of mountain peaks in the Glarus Alps, located on the border between the Swiss cantons of Glarus and Graubünden. They are composed of several summits on a long ridge, of which ...
'' between Elm and
Flims Flims ( rm, Flem) is a municipality in the Imboden Region in the Swiss canton of Graubünden. The town of Flims is dominated by the Flimserstein which one can see from almost anywhere in the area. Flims consists of the village of Flims (called ...
(in the same cliff is a natural hole called the Martinsloch).


World Heritage

Thrust faults of this kind are not uncommon in many mountain chains around the world, but the Glarus thrust is a well accessible example and has as such played an important role in the development of
geological Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other E ...
knowledge on
mountain building Mountain formation refers to the geological processes that underlie the formation of mountains. These processes are associated with large-scale movements of the Earth's crust (tectonic plates). Folding, faulting, volcanic activity, igneous intr ...
. For this reason the area in which the thrust is found was declared a
geotope A geotope is the geological component of the abiotic matrix present in an ecotope. Example geotopes might be an exposed outcrop of rocks, an erratic boulder, a grotto or ravine, a cave, an old stone wall marking a property boundary, and so forth. ...
, a geologic
UNESCO The United Nations Educational, Scientific and Cultural Organization is a List of specialized agencies of the United Nations, specialized agency of the United Nations (UN) aimed at promoting world peace and security through international coope ...
World Heritage Site A World Heritage Site is a landmark or area with legal protection by an international convention administered by the United Nations Educational, Scientific and Cultural Organization (UNESCO). World Heritage Sites are designated by UNESCO for ...
, under the name "Swiss Tectonic Arena Sardona." The area of this "tectonic arena" encompasses 32,850
hectare The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100- metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre i ...
s of mainly mountainous landscape in 19 communities between the
Surselva Surselva Region is one of the eleven administrative districts in the canton of Graubünden in Switzerland. It was created on 1 January 2017 as part of a reorganization of the canton.Linth The Linth (pronounced "lint") is a Swiss river that rises near the village of Linthal in the mountains of the canton of Glarus, and eventually flows into the Obersee section of Lake Zurich. It is about in length. The water power of the Lin ...
tal and Walensee. In the arena are a number of peaks higher than 3000 meters, such as Surenstock (its Romansh name is ''Piz Sardona'', from which the name comes),
Ringelspitz The Ringelspitz (also known as ''Piz Barghis'') is a mountain of the Glarus Alps, located on the border between the Swiss cantons of St. Gallen and Graubünden. Reaching a height of 3,248 metres above sea level, it is the highest summit in th ...
and
Pizol The Pizol is a mountain in the Glarus Alps of northeastern Switzerland, overlooking Wangs in the canton of St. Gallen St. Gallen or traditionally St Gall, in German; it, San Gallo; rm, Son Gagl) is a Swiss city and the capital o ...
. In 2006 the
Swiss Swiss may refer to: * the adjectival form of Switzerland *Swiss people Places * Swiss, Missouri *Swiss, North Carolina * Swiss, West Virginia *Swiss, Wisconsin Other uses * Swiss-system tournament, in various games and sports * Swiss Internation ...
government made a first proposal to declare the region World Heritage to the
International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
(IUCN). The IUCN then did not find the area to have an extraordinary or universal value and denied the proposal. The Swiss made a new, this time successful proposal in March 2008. The region was declared a World Heritage Site in July 2008, because "the area displays an exceptional example of mountain building through continental collision and features excellent geological sections through
tectonic Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents ...
thrust." The
American Museum of Natural History The American Museum of Natural History (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 int ...
in
New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...
exposes a full-scale reconstruction of the Glarus thrust.


History

The first naturalist to examine the Glarus thrust was Hans Conrad Escher von der Linth (1767–1823). Escher von der Linth discovered that, contradictory to Steno's
law of superposition The law of superposition is an axiom that forms one of the bases of the sciences of geology, archaeology, and other fields pertaining to geological stratigraphy. In its plainest form, it states that in undeformed stratigraphic sequences, the ...
, older rocks are on top of younger ones in certain
outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. Features Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficia ...
s in Glarus. His son
Arnold Escher von der Linth Arnold Escher von der Linth (8 June 1807 in Zürich12 July 1872) was a Swiss geologist, the son of Hans Conrad Escher von der Linth (1767–1823). He made the first ascent of the Lauteraarhorn on 8 August 1842 together with Pierre Jean Édouard ...
(1807–1872), the first professor in geology at the ETH at Zürich, mapped the structure in more detail and concluded that it could be a huge thrust. At the time, most geologists believed in the theory of
geosyncline A geosyncline (originally called a geosynclinal) is an obsolete geological concept to explain orogens, which was developed in the late 19th and early 20th centuries, before the theory of plate tectonics was envisaged. Şengör (1982), p. 11 A geo ...
s, which states that mountains are formed by vertical movements within the Earth's crust. Escher von der Linth had therefore difficulty with explaining the size of the thrust fault. In 1848 he invited the British geologist
Roderick Murchison Sir Roderick Impey Murchison, 1st Baronet, (19 February 1792 – 22 October 1871) was a Scottish geologist who served as director-general of the British Geological Survey from 1855 until his death in 1871. He is noted for investigating and ...
, an international authority, to come and look at the structure. Murchison was familiar with larger thrust faults in Scotland and agreed with Escher's interpretation. However, Escher himself felt insecure about his idea and when he published his observations in 1866 he instead interpreted the Glarus thrust as two large overturned narrow
anticline In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is t ...
s. This hypothesis was rather absurd, as he admitted himself in private. Escher's successor as professor at Zürich,
Albert Heim Albert Heim (12 April 184931 August 1937) was a Swiss geologist, noted for his three-volume ''Geologie der Schweiz''. Born in Zürich, he was educated at Zürich and Berlin universities. Very early in life he became interested in the physical f ...
(1849–1937), initially stuck to his predecessor's interpretation of two anticlines. However, some geologists favoured the idea of a thrust. One of them was Marcel Alexandre Bertrand (1847–1907), who interpreted the structure as a thrust in 1884, after reading Heims observations. Bertrand was familiar with the Faille du Midi (
Variscan orogeny The Variscan or Hercynian orogeny was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea. Nomenclature The name ''Variscan'', comes f ...
), a large thrust fault in the
Belgian Belgian may refer to: * Something of, or related to, Belgium * Belgians, people from Belgium or of Belgian descent * Languages of Belgium, languages spoken in Belgium, such as Dutch, French, and German *Ancient Belgian language, an extinct languag ...
Ardennes The Ardennes (french: Ardenne ; nl, Ardennen ; german: Ardennen; wa, Årdene ; lb, Ardennen ), also known as the Ardennes Forest or Forest of Ardennes, is a region of extensive forests, rough terrain, rolling hills and ridges primarily in Be ...
. Meanwhile, British geologists began to recognize the nature of thrust faults in the
Scottish Highlands The Highlands ( sco, the Hielands; gd, a’ Ghàidhealtachd , 'the place of the Gaels') is a historical region of Scotland. Culturally, the Highlands and the Lowlands diverged from the Late Middle Ages into the modern period, when Lowland S ...
. In 1883, Archibald Geikie accepted that the Highlands are a thrust system. Swiss geologists Hans Schardt and Maurice Lugeon then discovered in 1893 that in western Switzerland, Jurassic rock layers are on top of younger molasse too, and argued that the structure of the Alps is a large
stack Stack may refer to: Places * Stack Island, an island game reserve in Bass Strait, south-eastern Australia, in Tasmania’s Hunter Island Group * Blue Stack Mountains, in Co. Donegal, Ireland People * Stack (surname) (including a list of people ...
of
nappe In geology, a nappe or thrust sheet is a large sheetlike body of rock that has been moved more than or above a thrust fault from its original position. Nappes form in compressional tectonic settings like continental collision zones or on the o ...
s, large sheets of rock that had been thrust on top of each other. At the turn of the century, Heim was also convinced of the new theory. He and other Swiss geologists now started mapping the nappes of Switzerland in more detail. From that moment on, geologists began recognizing large thrusts in many mountain chains around the world. However, it was still not understood where the huge forces that moved the nappes came from. Only with the arrival of plate tectonic theory in the 1950s an explanation was found. In plate tectonics, the horizontal movement of
tectonic plate Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...
s over the Earth's soft
asthenosphere The asthenosphere () is the mechanically weak and ductile region of the upper mantle of Earth. It lies below the lithosphere, at a depth between ~ below the surface, and extends as deep as . However, the lower boundary of the asthenosphere is ...
causes horizontal forces within the crust. Presently, geologists believe most mountain chains are formed by convergent movements between tectonic plates.


Notes and references


Literature

*


External links

{{Portal bar, Switzerland Geology of the Alps World Heritage Sites in Switzerland Flims Tourist attractions in Switzerland Geography of the canton of Glarus Geography of Graubünden Geography of the canton of St. Gallen Glarus–Graubünden border Protected areas of the Alps