Geochemistry and geochronology of Mississippian volcanic rocks from SW Mongolia: Implications for terrane subdivision and magmatic arc activity in the Trans-Altai Zone

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F18%3A10379415" target="_blank" >RIV/00216208:11310/18:10379415 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.1016/j.jseaes.2018.06.029" target="_blank" >https://doi.org/10.1016/j.jseaes.2018.06.029</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jseaes.2018.06.029" target="_blank" >10.1016/j.jseaes.2018.06.029</a>

Result language

angličtina

Original language name

Geochemistry and geochronology of Mississippian volcanic rocks from SW Mongolia: Implications for terrane subdivision and magmatic arc activity in the Trans-Altai Zone

Original language description

Baaran and Baytag &quot;terranes&quot; form important part of the Trans-Altai Zone of the Central Asian Orogenic Belt in the SW Mongolia. The Trans-Altai Zone represents an oceanic domain built by Ordovician to Devonian ophiolites covered by Devonian-Carboniferous oceanic sediments. This oceanic assemblage was intruded by a spectrum of Carboniferous volcanic rocks ranging from basalts to rhyolites (325.6 +/- 1.4 Ma to 351.0 +/- 5.9 Ma; LA-ICP-MS U-Pb dating on zircon) that display similar whole-rock trace-element and Sr-Nd isotopic signatures regardless their silica contents and the &quot;terrane&quot; they belong to. They are normal-K calc-alkaline rocks whose NMORB-normalized multielement patterns show an arc-like enrichment in LILE (Large Ion Lithophile Elements) and deep negative TNT (Ta, Nb, Ti) anomalies. Based on the relatively high Nb/Yb and Th/Yb ratios, the arc was probably formed on immature continental rather than typical oceanic crust. Low (Sr-87/Sr-86)1 (0.7043-0.7047), high epsilon(350)(Nd) (+5.2 to = +5.8) and the observed in-situ Hf isotopic variation in dated zircons (epsilon(t)(Hf) = +7.4 to +13) are all attributed to a partial melting of primitive and youthful (Neoproterozoic-Ordovician) arc-type lower continental crust (metamorphosed intermediate-acid igneous rocks and/or arc-derived greywackes), augmented with, and most likely facilitated by, contemporaneous arc-related basaltic intrusions. A distinct possibility remains the previously formulated model assuming that the Carboniferous magmatism in Gobi-Altai and Trans-Altai zones sampled the juvenile Neoproterozoic to Cambrian arc crust relaminated under the Ordovician-Devonian oceanic crust. In any case, the studied arc association, together with lithological sequence of ophiolites, can be closely correlated with the Dulate arc in eastern Junggar. It is proposed that the two arc sequences form a single belt, c. 500 km long, that represents one of the main known arc structures in the Central Asian Orogenic Belt.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10505 - Geology

Project

<a href="/en/project/GA17-17540S" target="_blank" >GA17-17540S: Contrasting mechanisms of formation of the Pangea supercotinent: new insights into formation of continental crust</a><br>

Continuities

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

Publication year

2018

Confidentiality

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

Name of the periodical

Journal of Asian Earth Sciences

ISSN

1367-9120

e-ISSN

—

Volume of the periodical

164

Issue of the periodical within the volume

SEP 2018

Country of publishing house

GB - UNITED KINGDOM

Number of pages

22

Pages from-to

322-343

UT code for WoS article

000442706000021

EID of the result in the Scopus database

2-s2.0-85049334518