Petrostructural and Geochronological Constraints on Devonian Extension-Shortening Cycle in the Chinese Altai: Implications for Retreating-Advancing Subduction

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F22%3A00000158" target="_blank" >RIV/00025798:_____/22:00000158 - isvavai.cz</a>

Výsledek na webu

<a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021TC007195" target="_blank" >https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021TC007195</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1029/2021TC007195" target="_blank" >10.1029/2021TC007195</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Petrostructural and Geochronological Constraints on Devonian Extension-Shortening Cycle in the Chinese Altai: Implications for Retreating-Advancing Subduction

Popis výsledku v původním jazyce

Structural and metamorphic effects of a Devonian extension-shortening cycle in the NWChinese Altai were investigated using combined structural-petrological analysis and zircon and monazite U-Pbgeochronology. Structural observations revealed a ubiquitous, sub-horizontal metamorphic fabric (S1), whichwas originally sub-parallel with horizontal bedding (S0) of supracrustal Devonian volcanic-sedimentary basins.This metamorphic fabric is defined by a sillimanite-bearing migmatitic gneissosity associated with extensionalshear bands and a cordierite-bearing schistosity in the orogenic lower and middle crust, respectively.Staurolite relics preserved in the S1 fabric are interpreted as relics of older, higher pressure Barrovian-typemetamorphism. These structural-metamorphic features are correlated with decompression and heatingand interpreted as reflecting a crustal-scale extensional phase. S1 was folded to form N-S-oriented uprightantiforms cored by migmatites and locally transposed by steep S2 foliation during a ∼W-E-directed shortening(in current coordinates). Andalusite and cordierite overgrew the migmatitic S2 foliation attesting to decreasingpressure associated with vertical extrusion of migmatites in cores of F2 antiforms. New U-Pb age data fromsubhorizontally foliated migmatites suggest that the D1 extension started at least before ∼410 Ma. Age data ofsyn-D2 granite intrusions and dykes constrain the D2 shortening starting soon after D1 extension and endingat ∼378 Ma. Combined with regional data, cycles of extensional and contractional tectonic regimes can bedefined, which also show eastward migration along-strike of the Altai range. Such extension-shortening cyclescould result from alternating retreating and advancing subduction, which governed the evolution of the Altaiaccretionary system from the Ordovician until the Carboniferous.

Název v anglickém jazyce

Petrostructural and Geochronological Constraints on Devonian Extension-Shortening Cycle in the Chinese Altai: Implications for Retreating-Advancing Subduction

Popis výsledku anglicky

Structural and metamorphic effects of a Devonian extension-shortening cycle in the NWChinese Altai were investigated using combined structural-petrological analysis and zircon and monazite U-Pbgeochronology. Structural observations revealed a ubiquitous, sub-horizontal metamorphic fabric (S1), whichwas originally sub-parallel with horizontal bedding (S0) of supracrustal Devonian volcanic-sedimentary basins.This metamorphic fabric is defined by a sillimanite-bearing migmatitic gneissosity associated with extensionalshear bands and a cordierite-bearing schistosity in the orogenic lower and middle crust, respectively.Staurolite relics preserved in the S1 fabric are interpreted as relics of older, higher pressure Barrovian-typemetamorphism. These structural-metamorphic features are correlated with decompression and heatingand interpreted as reflecting a crustal-scale extensional phase. S1 was folded to form N-S-oriented uprightantiforms cored by migmatites and locally transposed by steep S2 foliation during a ∼W-E-directed shortening(in current coordinates). Andalusite and cordierite overgrew the migmatitic S2 foliation attesting to decreasingpressure associated with vertical extrusion of migmatites in cores of F2 antiforms. New U-Pb age data fromsubhorizontally foliated migmatites suggest that the D1 extension started at least before ∼410 Ma. Age data ofsyn-D2 granite intrusions and dykes constrain the D2 shortening starting soon after D1 extension and endingat ∼378 Ma. Combined with regional data, cycles of extensional and contractional tectonic regimes can bedefined, which also show eastward migration along-strike of the Altai range. Such extension-shortening cyclescould result from alternating retreating and advancing subduction, which governed the evolution of the Altaiaccretionary system from the Ordovician until the Carboniferous.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

<a href="/cs/project/GX19-27682X" target="_blank" >GX19-27682X: Hlavní mechanismy periferálního kontinentálního růstu během superkontinentálního cyklu</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2022

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Tectonics

ISSN

0278-7407

e-ISSN

—

Svazek periodika

41

Číslo periodika v rámci svazku

9 : e2021TC007195

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

32

Strana od-do

nestránkováno

Kód UT WoS článku

000848243800001

EID výsledku v databázi Scopus

2-s2.0-85139113977