UHP kyanite eclogite associated with garnet peridotite and diamond-bearing granulite, northern Bohemian Massif

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F15%3A00107798" target="_blank" >RIV/00216224:14310/15:00107798 - isvavai.cz</a>

Alternative codes found

RIV/00025798:_____/15:00000355

Result on the web

<a href="https://www.sciencedirect.com/science/article/pii/S0024493715000249" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0024493715000249</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.lithos.2015.01.016" target="_blank" >10.1016/j.lithos.2015.01.016</a>

Result language

angličtina

Original language name

UHP kyanite eclogite associated with garnet peridotite and diamond-bearing granulite, northern Bohemian Massif

Original language description

Kyanite eclogites enclosed in garnet peridotites may provide important information on P-T evolution of orogenic peridotites in deep subduction and collision zones. Kyanite eclogite interlayered with garnet peridotite occurs in the borehole T-7, in the Saxothuringian basement of the northern part of the Bohemian Massif. This orogenic peridotite of mantle origin is associated with felsic granulites, which contain diamond as a consequence of deep subduction of the continental crust. Here, we report on the metamorphic evolution of kyanite eclogite, which shows a well-preserved peak-pressure mineral assemblage of garnet, omphacite, kyanite and phengite. Conventional geothermobarometry, average PT method and thermodynamic modelling constrain the metamorphic conditions of this assemblage up to 3.5-4.5 GPa at 900-1050 degrees C. Two compositional types of garnet, i.e., Mg-rich and Ca-rich, have been recognised. Thermodynamic modelling shows that the composition of Ca-rich garnet with X-Ca (0.35-037) in the core corresponds to stability of garnet at 3.5-4.5 GPa. Amphibole and zoisite are preserved as inclusions in garnet cores, and they are stable below 2.5 GPa, indicating that garnet grew at the expense of these phases at increasing P-T conditions during the prograde evolution of the rock. A post-peak metamorphism decompression and cooling are recorded by decrease of Ca-Eskola end-member in omphacite, drop in X-Mg and X-Grs at garnet rim and a very restricted formation of pargasitic amphibole in the matrix. The absence of symplectites after omphacite in the investigated eclogite may be due to a very low content of quartz and possibly also fluid in the rock. Our study suggests that kyanite-bearing eclogite underwent UHP metamorphism as a consequence of subduction, together with interlayered garnet peridotite. Both rocks were incorporated into the subducted continental crust (diamond-bearing granulites) during the Variscan orogeny.

Czech name

—

Czech description

—

Type

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

CEP classification

—

OECD FORD branch

10504 - Mineralogy

Project

<a href="/en/project/GA13-21450S" target="_blank" >GA13-21450S: Diamond and coesite-bearing North Bohemian granulites: study of diamond-forming media in a deep subduction zone and consequences for geodynamic models</a><br>

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

Lithos

ISSN

0024-4937

e-ISSN

1872-6143

Volume of the periodical

226

Issue of the periodical within the volume

JUN 1 2015

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

10

Pages from-to

255-264

UT code for WoS article

000356207000017

EID of the result in the Scopus database

2-s2.0-84941313620