Flysch

Flysch

Flysch is a sequence of sedimentary rocks that is deposited in a deep marine facies in the foreland basin of a developing orogen. Flysch is typically deposited during an early stage of the orogenesis, when the orogen evolves the foreland basin will become shallower and molasse will be deposited on top of the flysch. It is therefore called a syn-orogenic sediment (deposited contemporaneously with mountain building).

edimentological properties

Flysch consists of repeated sedimentary cycles with upwards fining of the sediments. At the bottom of each cycle are sometimes coarse conglomerates or breccias, which gradually evolve upwards into sandstone and shale/claystone. Typically the shales don't contain many fossils, the coarser sandstones often have fractions of micas ans glauconite.

Flysch is formed under deep marine circumstances, in a quite and low-energetic depostional environment. The coarser layers (which require higher energy) are disruptions in these circumstances, caused by pulsewise flows of mass transport from the forming orogenic wedge. In many cases the mass transports are represented in the record by turbidites.

Tectonics

Flysch deposits form at convergent plate boundaries at the stage of continental collision, often in remnant ocean basins that exist along the same boundary. The sedimental material in the flysch is derived from the forming mountains and deposited along the axis of the new mountain chain into remnant ocean basin. The same ocean basin is in the process of subducting under the orogenic wedge. As subduction continues, the flysch sediments are scraped off the down-going oceanic plate and are accreted onto the orogenic wedge. As a result, flysch deposits are often highly deformed by thrust faulting and folding.

Name and use

The name flysch was introduced in geologic literature by Swiss geologist Bernhard Studer in 1827. Studer used the term for the typical alternations of sandstone and shale in the foreland of the Alps. The name comes from the German word "fliessen", which means "to flow", because Studer thought flysch was deposited by rivers. The insight that flysch is actually a deep marine sediment typical for a particular plate tectonic setting came only much later. [aut|Laphart, T.; 2005: "Geologie der Schweiz", Ott Verlag, ISBN 3-7225-0007-9. (in German), see p. 64]

The name flysch is currently used in many mountain chains belonging to the Alpine belt. Well-known flysch deposits are found in the forelands of the Pyrenees and Carpathians and in tectonically similar regions in Italy, the Balkans and on Cyprus. In the northern Alps, the Flysch is also a lithostratigraphic unit.

References

Literature

*aut|Stanley, S.M.; 1999: "Earth System History", W.H. Freeman and Company, New York, ISBN 0-7167-2882-6. See p. 243.
*aut|Einsele, G.; 2000 (2nd ed.): "Sedimentary Basins, Evolution, Facies, and Sediment Budget", Springer, ISBN 3-540-66193-X. See p. 606-610.

External links

* [http://5.1911encyclopedia.org/F/FL/FLYSCH.htm Flysch] at "1911encyclopedia.org"


Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • Flysch — Saltar a navegación, búsqueda Los flyschs son formaciones rocosas formadas al mismo tiempo que las montañas que alternan capas de rocas duras (caliza, pizarra o areniscas) intercaladas con otras más blandas (margas y arcillas) y que estas capas… …   Wikipedia Español

  • flysch — [ fliʃ ] n. m. • 1875; mot suisse alémanique ♦ Géol. Empilement de sédiments détritiques déposés par un même courant de turbidité. Des flyschs. ● flysch nom masculin (mot dialectal de la Suisse allemande) Formation sédimentaire détritique,… …   Encyclopédie Universelle

  • Flysch — 〈n. 11; unz.; Geol.〉 Sedimente, die während des Aufstiegs der Faltengebirge in Vorlandtiefen abgesetzt wurden * * * Flysch   [flɪʃ; schweizerisch] das, (e)s, miteinander wechsellagernde, überwiegend marine, oft glimmer und glaukonitreiche… …   Universal-Lexikon

  • Flysch — (fl[=e]sh), n. [A Swiss word, fr. G. fliessen to flow, melt.] (Geol.) A name given to the series of sandstones and schists overlying the true nummulitic formation in the Alps, and included in the Eocene Tertiary. [1913 Webster] …   The Collaborative International Dictionary of English

  • Flysch — Flysch, am nördlichen Alpenrand eine von der Schweiz nach Bayern hinreichende, zumeist aus hellgrau oder bläulichen und grünlichgrauen tonigen, sandigen und mergeligen, an Glimmerblättchen reichen Schichten bestehende Gesteinsreihe, die in ihrem… …   Lexikon der gesamten Technik

  • Flysch — Flysch, Abtheilung des Kreidegebirgs, enthält grauen Mergel u. Kalkschiefer, feinkörnigen, dunklen Mergel u. Kalksandstein, mit Breccien, Conglomeraten, Versteinerung von Fucusarten (daher Fucoiden Sandstein) u.a. Bildet einen Theil der Karpaten …   Pierer's Universal-Lexikon

  • Flysch — Flysch, Schiefer und Sandsteine, Faziesgebilde der obern Kreide und des untern Tertiärs, besonders in den östlichen Alpen u. in Oberitalien (hier Macigno genannt), s. Kreideformation und Tertiärformation …   Meyers Großes Konversations-Lexikon

  • Flysch — Flysch, meist alttertiäre mächtige Schichtengruppe von fast überall versteinerungsleeren dunklen Schiefern, Mergeln und Sandsteinen; in den Alpen, dem Apennin, den Karpathen …   Kleines Konversations-Lexikon

  • flysch — s.m.inv. ES ted. {{wmetafile0}} TS petr. insieme di sedimenti clastici, a strati più o meno regolari, depositati durante o immediatamente dopo un orogenesi in condizione di sedimentazione {{line}} {{/line}} DATA: 1892 …   Dizionario italiano

  • Flysch — [flɪʃ , fli:ʃ, österreichisch fly:ʃ], das, österreichisch der; [e]s (ein Gestein) …   Die deutsche Rechtschreibung

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”