Coupling of P–T–t–D histories of eclogite and metagreywacke—Insights to late Ordovician–Silurian crustal folding events recorded in the Beishan Orogen (NW China)

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F20%3A00000071" target="_blank" >RIV/00025798:_____/20:00000071 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1111/jmg.12531" target="_blank" >https://doi.org/10.1111/jmg.12531</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1111/jmg.12531" target="_blank" >10.1111/jmg.12531</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Coupling of P–T–t–D histories of eclogite and metagreywacke—Insights to late Ordovician–Silurian crustal folding events recorded in the Beishan Orogen (NW China)

Popis výsledku v původním jazyce

The Beishan complex is composed of orthogneiss and metagreywacke that bothenclose bodies of eclogite and serves as a unique example for comparative petrologicalstudy of all these lithologies. The rocks show the earliest regional steep N-Sstriking fabric (S2) preserved in low strain domains that are reworked by ubiquitoussteep N-NE dipping cleavage (S3). The eclogite shows an almost isotropic fabricdefined by an M1 assemblage of Grt–Cpx–Amp–Qz–Rt–Ilm that is locally retrogressedto M2-3 amphibolite facies mineral assemblages, with P–T peak at 20–21kbar and 750–775°C and retrogression to 2–3 kbar and 530–550°C. The typical mineralassemblage of the host metagreywackes is Bt–Ms–Pl–Qz&#8722;Chl–Ilm±Grt. RareAl-rich metagreywacke layers are composed of Grt–Ky–St±Sil&#8722;And–Bt–Ms–Pl–Qz±Chl±Rt–Ilm giving a P–T path with peak at 8–8.5 kbar and ~670°C correlatedwith the S2 fabric and retrogression to ~2.5 kbar and 525–550°C correlated with theS3 foliation. In two eclogite samples, the garnet-whole rock-clinopyroxene Lu–Hfisochrons give ages of 461.9±1.6 Ma and 462.0±6.2 Ma interpreted as reflecting averageage of garnet formation, and Sm–Nd isochrons give ages of 453.6±2.7 Ma and452.8±3.0 Ma interpreted as dating near-peak metamorphism. In metagreywacke,in-situ U–Pb dating of monazite gives two groups of ages of 445–440 Ma (Mnzcores) and 436–429 Ma (Mnz rims), interpreted as reflecting the metamorphic peakand retrogression. Our results show that eclogite was formed during Ordovicianby subduction of a continental crust (D1). Eclogite and metagreywacke underwentpartly decoupled P–T–t–D paths until their juxtaposition at mid-crustal levels duringa first late Ordovician–early Silurian D2 shortening. Coupling of their P–T–t–Dpaths occurred during exhumation in the Silurian and a second and orthogonal D3shortening event. The data from the Beishan Orogen are consistent with a collisionalintra-Gondwanan orogen located south of the Central Asian Orogenic Belt.

Název v anglickém jazyce

Coupling of P–T–t–D histories of eclogite and metagreywacke—Insights to late Ordovician–Silurian crustal folding events recorded in the Beishan Orogen (NW China)

Popis výsledku anglicky

The Beishan complex is composed of orthogneiss and metagreywacke that bothenclose bodies of eclogite and serves as a unique example for comparative petrologicalstudy of all these lithologies. The rocks show the earliest regional steep N-Sstriking fabric (S2) preserved in low strain domains that are reworked by ubiquitoussteep N-NE dipping cleavage (S3). The eclogite shows an almost isotropic fabricdefined by an M1 assemblage of Grt–Cpx–Amp–Qz–Rt–Ilm that is locally retrogressedto M2-3 amphibolite facies mineral assemblages, with P–T peak at 20–21kbar and 750–775°C and retrogression to 2–3 kbar and 530–550°C. The typical mineralassemblage of the host metagreywackes is Bt–Ms–Pl–Qz&#8722;Chl–Ilm±Grt. RareAl-rich metagreywacke layers are composed of Grt–Ky–St±Sil&#8722;And–Bt–Ms–Pl–Qz±Chl±Rt–Ilm giving a P–T path with peak at 8–8.5 kbar and ~670°C correlatedwith the S2 fabric and retrogression to ~2.5 kbar and 525–550°C correlated with theS3 foliation. In two eclogite samples, the garnet-whole rock-clinopyroxene Lu–Hfisochrons give ages of 461.9±1.6 Ma and 462.0±6.2 Ma interpreted as reflecting averageage of garnet formation, and Sm–Nd isochrons give ages of 453.6±2.7 Ma and452.8±3.0 Ma interpreted as dating near-peak metamorphism. In metagreywacke,in-situ U–Pb dating of monazite gives two groups of ages of 445–440 Ma (Mnzcores) and 436–429 Ma (Mnz rims), interpreted as reflecting the metamorphic peakand retrogression. Our results show that eclogite was formed during Ordovicianby subduction of a continental crust (D1). Eclogite and metagreywacke underwentpartly decoupled P–T–t–D paths until their juxtaposition at mid-crustal levels duringa first late Ordovician–early Silurian D2 shortening. Coupling of their P–T–t–Dpaths occurred during exhumation in the Silurian and a second and orthogonal D3shortening event. The data from the Beishan Orogen are consistent with a collisionalintra-Gondwanan orogen located south of the Central Asian Orogenic Belt.

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

2020

Kód důvěrnosti údajů

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

Název periodika

Journal of Metamorphic Geology

ISSN

0263-4929

e-ISSN

—

Svazek periodika

38

Číslo periodika v rámci svazku

6

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

37

Strana od-do

555-591

Kód UT WoS článku

000553417600001

EID výsledku v databázi Scopus

2-s2.0-85088816501