Complex mid-crustal flow within a growing granite-migmatite dome: An example from the Variscan belt illustrated by the anisotropy of magnetic susceptibility and fabric modelling

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F19%3A10400707" target="_blank" >RIV/00216208:11310/19:10400707 - isvavai.cz</a>

Alternative codes found

RIV/00025798:_____/18:00000206

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=m_TwkU0mMB" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=m_TwkU0mMB</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1002/gj.3335" target="_blank" >10.1002/gj.3335</a>

Result language

angličtina

Original language name

Complex mid-crustal flow within a growing granite-migmatite dome: An example from the Variscan belt illustrated by the anisotropy of magnetic susceptibility and fabric modelling

Original language description

This study describes anisotropy of magnetic susceptibility (AMS) of migmatites associated with crustally derived granites of the Pelhrimov core complex, Bohemian Massif. In combination with numerical modelling, we use this case example to discuss some of the general complexities related to interpreting flow patterns of anatectic lower and middle crust from magnetic fabric during growth of metamorphic domes. Magnetic lineations, reflecting tiling or zone axis of magnetically oblate grains, commonly tend to develop along the principal stretching direction. Our fabric modelling, however, shows that a lineation may also develop at a high angle to the overall flow (tectonic transport) direction as a relict of a pre-existing fabric or due to a component of core complex axis-parallel stretching and may be maintained for a significant period of time. Furthermore, we demonstrate that the finite magnetic fabric orientation is largely independent on the initial migmatite fabric intensity (formed before dome growth) but is rather a function of (a) shear strain, causing magnetic foliation and lineation to rotate towards the shear plane, and (b) magnitude of dome growth, causing their external rotation. Similarly, the degree of anisotropy P is also a function of accumulated shear strain and increases over time. These findings suggest that low fabric intensities may point to rapidly cooling, less sheared domains that are more likely to preserve early formed fabrics. In dome limbs undergoing protracted simple shear, low and high degrees of oblateness (as expressed by the shape parameter T) may discriminate between domains with weak and strong initial fabrics and may thus be used to map out domains with different strain histories and perhaps also with different melt proportions and rheological behaviour within metamorphic domes.

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

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OECD FORD branch

10505 - Geology

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

2019

Confidentiality

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

Name of the periodical

Geological Journal

ISSN

0072-1050

e-ISSN

—

Volume of the periodical

54

Issue of the periodical within the volume

6

Country of publishing house

GB - UNITED KINGDOM

Number of pages

19

Pages from-to

3681-3699

UT code for WoS article

000496020400027

EID of the result in the Scopus database

2-s2.0-85057232869