Pregledni naučni rad / Review scientific paper
UDC: 551.43:910.3(4)(23.0)
DOI: 10.7251/HER2428007S
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Dragan Šironjić1
1Univerzitet u Gracu, Odjeljenje za geonauke, Grac, Austrija
Sažetak: Alpi su orogenski pojas koji je rezultat otvaranja i zatvaranja dva okeana: Pijemont-Ligurskog i Valais okeana. Subdukcija okeanske litosfere je pokretačka snaga iza zatvaranja okeana, što obično dovodi do formiranja vulkanskih lukova. Međutim, ova uobičajena karakteristika subdukcije tipa Venedi-Beniof ne može se pronaći u Alpskom orogenu. Štaviše, podaci o magmatskim, sedimentnim i metamorfnim stijenama ne otkrivaju nikakvu magmatsku aktivnost tokom subdukcije Pijemont-Ligurskog okeana i visokopripremne metamorfoze. Podaci dobijeni iz prikupljenih stijena pokazuju 50 miliona godina magmatske neaktivnosti. Ovo dovodi do zaključka da se orogeneza odvijala bez prisustva magme. Glavni razlozi za nedostatak magmatizma mogu se pripisati nedovoljnoj subdukciji hidriranih litologija, što je povezano sa pokretanjem subdukcije na pasivnim marginama. Subdukcija „suvih“ litologija nije bila dovoljna da proizvede značajne količine magme u klinastoj geometriji. Takva arhitektura je omogućila akreciju hidriranog materijala. Kada se pažljivo posmatraju, karakteristike alpinske subdukcije ukazuju na subdukciju tipa Ampferer, kako je utvrđeno početkom 20. vijeka.
Ključne riječi: subdukcija Ampferer tipa, subdukcija Beniof tipa, Alpi, orogeneza, amagmatsko pokretanje subdukcije.
Dragan Šironjić1
1University of Graz, Department of Earth Sciences, Graz, Austria
Abstract: The Alps are an orogenic belt that is the result of the opening and closing of the two oceans: The Piedmont-Liguria and Valais Ocean. Typically, the subduction of the oceanic lithosphere is the driving force behind the ocean closure which is commonly followed by the formation of volcanic arcs. However, this common characteristic of Wenedi-Benioff subduction type cannot be found in the Alpine orogen. Moreover, igneous, sedimentary, and metamorphic data reveal no magmatic activity during subduction of Piedmont-Liguria Ocean and high-pressure metamorphism. Data obtained from gathered rocks reveal a 50 million years magmatic inactivity. This leads to the conclusion that during this phase Alpine orogeny was amagmatic. The main reasons behind this lack of magmatism can be attributed to the insufficient subduction of hydrated lithologies, which is related to the subduction initiation at the passive margins. Subduction of “dry” lithologies was not sufficient to produce significant amounts of magma in the wedge-shaped geometry. Such architecture allowed the accretion of hydrated material. When closely observed, features of Alpine subduction are pointing in direction of Ampferer type subduction, as investigated at the beginning of 20th century.
Key words: Ampferer type subduction, Benioff type subduction, Alps, orogeny, amagmatic initiation of subduction.
CITIRAJTE (Cite this article):
Šironjić, D. (2024). Zašto u Alpima nema vulkanskog luka? Glasnik/Herald, 28, 7‒15. https://doi.org/10.7251/HER2428007S
Šironjić, D. (2024). Why Is There no Volcanic Arc in the Alps? Glasnik/Herald, 28, 7‒15. https://doi.org/10.7251/HER2428007S
Autor za korespondenciju: Dragan Šironjić, Univerzitet u Gracu, Odjeljenje za geonauke, Univerzitetski trg 3, 8010 Grac, Austrija, E-mail: dragan.sironjic@edu.uni-graz.at
Corresponding author: Dragan Šironjić, University of Graz, Department of Earth Sciences, Universitaetsplatz 3, 8010 Graz, Austria, E-mail: dragan.sironjic@edu.uni-graz.at