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Detachment folding of partially molten crust in accretionary orogens: A new magma-enhanced vertical mass and heat transfer mechanism
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SYSNO ASEP 0483167 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Detachment folding of partially molten crust in accretionary orogens: A new magma-enhanced vertical mass and heat transfer mechanism Tvůrce(i) Lehmann, J. (ZA)
Schulmann, K. (CZ)
Lexa, O. (CZ)
Závada, Prokop (GFU-E) ORCID, RID
Štípská, P. (CZ)
Hasalová, Pavlína (GFU-E) RID
Belyanin, G. (ZA)
Corsini, M. (FR)Zdroj.dok. Lithosphere. - : GeoScienceWorld - ISSN 1941-8264
Roč. 9, č. 6 (2017), s. 889-909Poč.str. 21 s. Forma vydání Tištěná - P Jazyk dok. eng - angličtina Země vyd. US - Spojené státy americké Klíč. slova continental crust ; shear-zone ; gneiss domes Vědní obor RIV DB - Geologie a mineralogie Obor OECD Geology Institucionální podpora GFU-E - RVO:67985530 UT WOS 000417374300003 EID SCOPUS 85035132515 DOI https://doi.org/10.1130/L670.1 Anotace We use structural, petrographic, and geochronological data to examine processes of exhumation of partially molten crust in the Late Devonian-early Carboniferous Chandman dome in the Mongolian tract of the Central Asian Orogenic Belt. The dome is composed of a magmatite-migmatite core and a low-grade metamorphic envelope of early Paleozoic metasediments and Carboniferous clastics. Its tectonic evolution can be divided into three main stages. The oldest fabric is a subhorizontal foliation, S-1, in migmatites that is subparallel to the magmatic foliation in granitoids and to the greenschist facies schistosity in the enveloping metasediments. This event is interpreted as a result of horizontal deep crustal flow at depths of 20-25 km. The S-1 layering was subsequently transposed into a new foliation, S-2, or affected by open to close upright F-2 folds that are locally truncated by steep walls of diatexites, suggesting influx of partially molten crust into fold cores. The shallow-dipping magmatic foliation in granitoids is locally reworked by vertical magmatic to gneissic S-2 fabrics. Syn-S-2 metamorphic assemblages and synkinematic to postkinematic cordierite point to exhumation of the migmatites and granitoids from 20-25 km to similar to 10 km, and concomitant isobaric heating of the surrounding upper crust. New Ar-40/Ar-39 ages of 350-340 Ma from both the high-grade core and the metamorphic mantle overlap with previously published crystallization ages of 360-340 Ma, suggesting that magmatism and cooling in the upper crust are partly synchronous. Late syn-D-2, S-2-parallel leucogranite sheets crosscutting both the magmatic core and the mantling migmatites either exploit S-2 or crosscut horizontal S-1 fabrics. They are interpreted as brittle expulsion of magma during ongoing syn-D-2 exhumation. Pracoviště Geofyzikální ústav Kontakt Hana Krejzlíková, kniha@ig.cas.cz, Tel.: 267 103 028 Rok sběru 2018
Počet záznamů: 1