UHP-UHT peak conditions and near-adiabatic exhumation path of
diamond-bearing garnet-clinopyroxene rocks from the Eger
Crystalline Complex, North Bohemian Massif

J 2016

UHP-UHT peak conditions and near-adiabatic exhumation path of diamond-bearing garnet-clinopyroxene rocks from the Eger Crystalline Complex, North Bohemian Massif

HAIFLER, Jakub and Jana KOTKOVÁ

Basic information

Original name

UHP-UHT peak conditions and near-adiabatic exhumation path of diamond-bearing garnet-clinopyroxene rocks from the Eger Crystalline Complex, North Bohemian Massif

Authors

HAIFLER, Jakub (203 Czech Republic, belonging to the institution) and Jana KOTKOVÁ (203 Czech Republic, guarantor, belonging to the institution)

Edition

Lithos, Elsevier, 2016, 0024-4937

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10500 1.5. Earth and related environmental sciences

Country of publisher

Netherlands

Confidentiality degree

není předmětem státního či obchodního tajemství

References:

URL

Impact factor

Impact factor: 3.677

RIV identification code

RIV/00216224:14310/16:00087943

Organization unit

Faculty of Science

DOI

http://dx.doi.org/10.1016/j.lithos.2016.02.001

UT WoS

000373863900026

Keywords in English

Ultrahigh-pressure; Diamond; Ti-in-zircon; Granulite; Thermobarometry; Bohemian Massif

Abstract

V originále

Intermediate garnet-clinopyroxene rocks from the Eger Crystalline Complex, North Bohemian Massif, contain microdiamonds enclosed in garnet and zircon. P-T evolution of the rocks is evaluated using using univariant equilibria and thermodynamic modelling, and ternary feldspar solvus, Ti-in-garnet, Zr-in-rutile and Ti-in-zircon thermometry. Zircon mantle domains with diamond inclusions contain 111-189 ppm Ti, reflecting temperatures of 1037-1117 degrees C at c. 4.5-5.0 GPa. Ti-in-garnet thermometry using the Ti content of diamond-bearing garnet core yielded temperatures of 993-1039 degrees C at c. 5.0 GPa. An omphacite inclusion in garnet (reflecting c. 2.3-2.4 GPa at c. 1050 degrees C) and metastably preserved kyanite represent relics of eclogite-facies conditions. The dominant high-pressure granulite-facies mineral assemblage of low-Ca garnet, diopsidic clinopyroxene, antiperthitic feldspar and quartz equilibrated at 1.8-2.1 GPa and c. 1050 degrees C. Thermodynamic modelling shows that a steep rimward decrease of XGrs and increase of X-Mg in garnet reflect omphacite and kyanite breakdown reactions producing garnet and plagioclase during decompression without heating. The Ti content in the rim zone of zircon (13-42 ppm), exsolved plagioclase and K-feldspar associated with matrix diopside and garnet rim, matrix rutile grains containing 2028-4390 ppm Zr and late biotite reflect temperatures of c. 830-900 degrees C at c. 1.4 GPa. Our results show that the garnet-clinopyroxene rocks from North Bohemia are UHP-UHT rocks which were extensively overprinted under HP granulite-facies conditions during rapid exhumation along a near-adiabatic P-T path. The UHT peak and UHT-HT exhumation distinguish this area from the other UHP terrains worldwide. The calculated UHP-UHT conditions are similar to those determined for the associated garnet peridotites, providing evidence for juxtaposition of these crustal and mantle rocks during deep Variscan subduction.

Links

GA13-21450S, research and development project

Name: Severočeské granulity obsahující diamant a coesit: studium médií vzniku diamantu v hluboké subdukční zóně a důsledky pro geodynamické modely

Investor: Czech Science Foundation

Citovat

HAIFLER, Jakub and Jana KOTKOVÁ. UHP-UHT peak conditions and near-adiabatic exhumation path of diamond-bearing garnet-clinopyroxene rocks from the Eger Crystalline Complex, North Bohemian Massif. Lithos. Elsevier, 2016, vol. 248, April, p. 366-381. ISSN 0024-4937. Available from: https://dx.doi.org/10.1016/j.lithos.2016.02.001.

@article{1345839,
   author = {Haifler, Jakub and Kotková, Jana},
   article_number = {April},
   doi = {http://dx.doi.org/10.1016/j.lithos.2016.02.001},
   keywords = {Ultrahigh-pressure; Diamond; Ti-in-zircon; Granulite; Thermobarometry; Bohemian Massif},
   language = {eng},
   issn = {0024-4937},
   journal = {Lithos},
   title = {UHP-UHT peak conditions and near-adiabatic exhumation path of diamond-bearing garnet-clinopyroxene rocks from the Eger Crystalline Complex, North Bohemian Massif},
   url = {http://www.sciencedirect.com/science/article/pii/S0024493716000621},
   volume = {248},
   year = {2016}
}

TY  - JOUR
ID  - 1345839
AU  - Haifler, Jakub - Kotková, Jana
PY  - 2016
TI  - UHP-UHT peak conditions and near-adiabatic exhumation path of diamond-bearing garnet-clinopyroxene rocks from the Eger Crystalline Complex, North Bohemian Massif
JF  - Lithos
VL  - 248
IS  - April
SP  - 366-381
EP  - 366-381
PB  - Elsevier
SN  - 00244937
KW  - Ultrahigh-pressure
KW  - Diamond
KW  - Ti-in-zircon
KW  - Granulite
KW  - Thermobarometry
KW  - Bohemian Massif
UR  - http://www.sciencedirect.com/science/article/pii/S0024493716000621
L2  - http://www.sciencedirect.com/science/article/pii/S0024493716000621
N2  - Intermediate garnet-clinopyroxene rocks from the Eger Crystalline Complex, North Bohemian Massif, contain microdiamonds enclosed in garnet and zircon. P-T evolution of the rocks is evaluated using using univariant equilibria and thermodynamic modelling, and ternary feldspar solvus, Ti-in-garnet, Zr-in-rutile and Ti-in-zircon thermometry. Zircon mantle domains with diamond inclusions contain 111-189 ppm Ti, reflecting temperatures of 1037-1117 degrees C at c. 4.5-5.0 GPa. Ti-in-garnet thermometry using the Ti content of diamond-bearing garnet core yielded temperatures of 993-1039 degrees C at c. 5.0 GPa. An omphacite inclusion in garnet (reflecting c. 2.3-2.4 GPa at c. 1050 degrees C) and metastably preserved kyanite represent relics of eclogite-facies conditions. The dominant high-pressure granulite-facies mineral assemblage of low-Ca garnet, diopsidic clinopyroxene, antiperthitic feldspar and quartz equilibrated at 1.8-2.1 GPa and c. 1050 degrees C. Thermodynamic modelling shows that a steep rimward decrease of XGrs and increase of X-Mg in garnet reflect omphacite and kyanite breakdown reactions producing garnet and plagioclase during decompression without heating. The Ti content in the rim zone of zircon (13-42 ppm), exsolved plagioclase and K-feldspar associated with matrix diopside and garnet rim, matrix rutile grains containing 2028-4390 ppm Zr and late biotite reflect temperatures of c. 830-900 degrees C at c. 1.4 GPa. Our results show that the garnet-clinopyroxene rocks from North Bohemia are UHP-UHT rocks which were extensively overprinted under HP granulite-facies conditions during rapid exhumation along a near-adiabatic P-T path. The UHT peak and UHT-HT exhumation distinguish this area from the other UHP terrains worldwide. The calculated UHP-UHT conditions are similar to those determined for the associated garnet peridotites, providing evidence for juxtaposition of these crustal and mantle rocks during deep Variscan subduction.
ER  -

HAIFLER, Jakub and Jana KOTKOVÁ. UHP-UHT peak conditions and near-adiabatic exhumation path of diamond-bearing garnet-clinopyroxene rocks from the Eger Crystalline Complex, North Bohemian Massif. \textit{Lithos}. Elsevier, 2016, vol.~248, April, p.~366-381. ISSN~0024-4937. Available from: https://dx.doi.org/10.1016/j.lithos.2016.02.001.

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