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@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 a 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, roč.~248, April, s.~366-381. ISSN~0024-4937. Dostupné z: https://dx.doi.org/10.1016/j.lithos.2016.02.001.
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