Petrogenesis of the Late Carboniferous Sagsai Pluton in the SE Mongolian Altai

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F16%3A00000113" target="_blank" >RIV/00025798:_____/16:00000113 - isvavai.cz</a>

Alternative codes found

RIV/00216208:11310/16:10326663

Result on the web

<a href="http://dx.doi.org/10.3190/jgeosci.207" target="_blank" >http://dx.doi.org/10.3190/jgeosci.207</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3190/jgeosci.207" target="_blank" >10.3190/jgeosci.207</a>

Result language

angličtina

Original language name

Petrogenesis of the Late Carboniferous Sagsai Pluton in the SE Mongolian Altai

Original language description

Sagsai Pluton intruded the low-grade metavolcanosedimentary complex of the Cambrian Tugrug Fm. in the Sagsai river valley SW of Tsogt soum, Gobi-Altai aimag (SE Mongolian Altai). This oval body (~9 × 12 km) is composed mainly of amphibole monzogabbros to quartz diorites, biotite to amphibole–biotite syenites to quartz monzonites. It is intruded by anatectic two-mica granites along the W rim. The abundant mafic microgranular enclaves enclosed by syenites to quartz monzonites are interpreted as an evidence of vigorous magma mingling and mixing. The newly obtained LA ICP-MS zircon ages for two samples of quartz monzonites gave emplacement ages of 307 ± 1 Ma and 309 ± 2 Ma (2σ),respectively. They have εtHf values varying broadly from +2.4 to +11.6 ruling out a participation of an old, mature crust. One gabbro body gave zircon U–Pb age of 322 ± 2 Ma with positive εtHf values of +7.4 to +11.5. The latter suggest an exclusively juvenile, depleted mantle-derived magma source. According to calculated P–T conditions, we propose three main stages in the Sagsai Pluton evolution. The gabbro started to grow at >1000 °C and 0.8–0.9 GPa. The ensuing magma mixing with crustal melts and final crystallization of gabbro occurred at similar P–T conditions (740–830 °C and 0.5–0.6 GPa) as partial melting of migmatite xenoliths in the Sagsai Pluton. The P–T conditions of the Sagsai Pluton final emplacement calculated from quartz syenite (c. 600 to 670 °C and 0.4–0.5 GPa) are consistent with the mineral assemblage in the contact aureole (cordierite–biotite and biotite–chlorite schists). The magmatic evolution of Sagsai Pluton confirms a model of deep lithosphere thermal anomaly associated with heterogeneous melting of crust in a postsubduction extensional regime, perhaps shortly after the slab break-off.

Czech name

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Czech description

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Type

J_x - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)

CEP classification

DB - Geology and mineralogy

OECD FORD branch

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Project

<a href="/en/project/GAP210%2F12%2F2205" target="_blank" >GAP210/12/2205: Crustal growth and construction of continental crust exemplified by Central Asian Orogenic Belt</a><br>

Continuities

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

Publication year

2016

Confidentiality

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

Name of the periodical

Journal of Geosciences

ISSN

1802-6222

e-ISSN

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Volume of the periodical

61

Issue of the periodical within the volume

1 special issue

Country of publishing house

CZ - CZECH REPUBLIC

Number of pages

26

Pages from-to

65-90

UT code for WoS article

000372458600005

EID of the result in the Scopus database

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