Geophysical and geochemical nature of relaminated arc-derived lower crust underneath oceanic domain in southern Mongolia

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F15%3A00000148" target="_blank" >RIV/00025798:_____/15:00000148 - isvavai.cz</a>

Alternative codes found

RIV/00216208:11310/15:10298031

Result on the web

<a href="http://onlinelibrary.wiley.com/doi/10.1002/2015TC003845/full" target="_blank" >http://onlinelibrary.wiley.com/doi/10.1002/2015TC003845/full</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1002/2015TC003845" target="_blank" >10.1002/2015TC003845</a>

Result language

angličtina

Original language name

Geophysical and geochemical nature of relaminated arc-derived lower crust underneath oceanic domain in southern Mongolia

Original language description

The Central Asian Orogenic Belt (CAOB) in southern Mongolia consists of E-W trending Neoproterozoic cratons and Silurian-Devonian oceanic tectonic zones. Previous study revealed that the Early Paleozoic accretionary wedge and the oceanic tectonic zone are underlain by a layer giving a homogeneous gravity signal. Forward gravity modelling suggests that this layer is not formed of high-density material typical of lower oceanic crust but is composed of low- to intermediate-density rocks resembling continental crust. The nature of this lower crust is constrained by the whole-rock geochemistry and zircon Hf isotopic signature of abundant Late Carboniferous high-K calc-alkaline and Early Permian A-type granitoids intruding the two Early Paleozoic domains. It is possible to explain the genesis of these granitoids by anatexis of juvenile, metaigneous (tonalitic-gabbroic) rocks of Late Cambrian age, the source of which is presumed to lie in the “Khantaishir” arc (520–495Ma) further north. In order to test this hypothesis, the likely modal composition and density of Khantaishir arc-like protoliths are thermodynamically modelled at granulite- and higher amphibolite-facies conditions. It is shown that the current average density of the lower crust inferred by gravity modelling (2730±20kg/m3) matches best metamorphosed leucotonalite to diorite. Based on these results, it is now proposed thatMongolian CAOB has an architecture in which the accretionary wedge and oceanic upper crust is underlain by allochthonous lower crust that originated in a Cambrian arc. A tectonic model explaining relamination of allochthonous felsic to intermediate lower crust beneath mafic upper crust is proposed.

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

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

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

Publication year

2015

Confidentiality

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

Name of the periodical

Tectonics

ISSN

0278-7407

e-ISSN

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Volume of the periodical

34

Issue of the periodical within the volume

5

Country of publishing house

US - UNITED STATES

Number of pages

24

Pages from-to

1030-1053

UT code for WoS article

000356621800011

EID of the result in the Scopus database

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