Ti- and Zr-minerals in calcite-dolomite marbles from the ultrahigh-pressure Kimi Complex, Rhodope mountains, Greece: Implications for the P-T evolution based on reaction textures, petrogenetic grids, and geothermobarometry

Alexander Proyer, Ioannis Baziotis, Evripidis Mposkos, Dieter Rhede

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6 Citations (Scopus)

Abstract

Rutile, titanite, and zircon formed as relatively coarse-grained accessory minerals in several samples of high-grade calcite-dolomite marble with an early ultrahigh-pressure history. These minerals decomposed to a texturally complex set of secondary minerals during subsequent stages of retrograde metamorphism. The reactions involve several generations of geikielite-ilmenite as well as zirconolite [(Ca,Th,U)Zr(Ti,Fe,Nb,Ta)(2)O-7], kassite/cafetite [CaTi2O4(OH)(2)/CaTi2O5 center dot H2O], Ti-bearing humite group minerals, thorianite, and sometimes euxenite [(Ca,U,Th,REE)(Nb,Ta,Ti)(2)(O,OH)(6)]. Stable coexistence of zircon and olivine is observed and stably coexisting titanite with olivine and/or humite-group minerals is reported here for the first time outside of carbonatites, kimberlites, or lamprophyres. Petrogenetic grids constructed for Ti- and Zr-bearing olivine/antigorite-saturated calcite-dolomite marbles show that geikielite is stable at highest pressures, followed by titanite and rutile, and that baddeleyite + diopside replaces zircon + calcite to higher pressures. The observed reaction textures are consistent with an earlier derived P-T path for the Kimi Complex. They corroborate a period of heating during decompression from 25 to 20 kbar and ca. 800 degrees C, where the assemblage olivine-diopside-spinel-rutile-zircon formed. This assemblage partially re-equilibrated during subsequent decompression and cooling, thus forming the observed reaction textures. Even though no memory of the UHP path is preserved in the accessory minerals, their reaction relationships turn out to be potentially very useful for geothermobarometry over a large range of metamorphic conditions.
Original languageEnglish
Pages (from-to)1429-1448
Number of pages20
JournalAmerican Mineralogist
Volume99
Issue number7
DOIs
Publication statusPublished - 2014

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Greece
Calcium Carbonate
calcite
marble
mountains
Minerals
dolomite
humite group
olivine
zircon
titanite
textures
rutile
Textures
texture
grids
minerals
mountain
accessory mineral
diopside

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@article{78be228239a2498d8fef16ba2b2259a2,
title = "Ti- and Zr-minerals in calcite-dolomite marbles from the ultrahigh-pressure Kimi Complex, Rhodope mountains, Greece: Implications for the P-T evolution based on reaction textures, petrogenetic grids, and geothermobarometry",
abstract = "Rutile, titanite, and zircon formed as relatively coarse-grained accessory minerals in several samples of high-grade calcite-dolomite marble with an early ultrahigh-pressure history. These minerals decomposed to a texturally complex set of secondary minerals during subsequent stages of retrograde metamorphism. The reactions involve several generations of geikielite-ilmenite as well as zirconolite [(Ca,Th,U)Zr(Ti,Fe,Nb,Ta)(2)O-7], kassite/cafetite [CaTi2O4(OH)(2)/CaTi2O5 center dot H2O], Ti-bearing humite group minerals, thorianite, and sometimes euxenite [(Ca,U,Th,REE)(Nb,Ta,Ti)(2)(O,OH)(6)]. Stable coexistence of zircon and olivine is observed and stably coexisting titanite with olivine and/or humite-group minerals is reported here for the first time outside of carbonatites, kimberlites, or lamprophyres. Petrogenetic grids constructed for Ti- and Zr-bearing olivine/antigorite-saturated calcite-dolomite marbles show that geikielite is stable at highest pressures, followed by titanite and rutile, and that baddeleyite + diopside replaces zircon + calcite to higher pressures. The observed reaction textures are consistent with an earlier derived P-T path for the Kimi Complex. They corroborate a period of heating during decompression from 25 to 20 kbar and ca. 800 degrees C, where the assemblage olivine-diopside-spinel-rutile-zircon formed. This assemblage partially re-equilibrated during subsequent decompression and cooling, thus forming the observed reaction textures. Even though no memory of the UHP path is preserved in the accessory minerals, their reaction relationships turn out to be potentially very useful for geothermobarometry over a large range of metamorphic conditions.",
author = "Alexander Proyer and Ioannis Baziotis and Evripidis Mposkos and Dieter Rhede",
year = "2014",
doi = "10.2138/am.2014.4710",
language = "English",
volume = "99",
pages = "1429--1448",
journal = "American Mineralogist",
issn = "0003-004X",
publisher = "Mineralogical Society of America",
number = "7",

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TY - JOUR

T1 - Ti- and Zr-minerals in calcite-dolomite marbles from the ultrahigh-pressure Kimi Complex, Rhodope mountains, Greece: Implications for the P-T evolution based on reaction textures, petrogenetic grids, and geothermobarometry

AU - Proyer, Alexander

AU - Baziotis, Ioannis

AU - Mposkos, Evripidis

AU - Rhede, Dieter

PY - 2014

Y1 - 2014

N2 - Rutile, titanite, and zircon formed as relatively coarse-grained accessory minerals in several samples of high-grade calcite-dolomite marble with an early ultrahigh-pressure history. These minerals decomposed to a texturally complex set of secondary minerals during subsequent stages of retrograde metamorphism. The reactions involve several generations of geikielite-ilmenite as well as zirconolite [(Ca,Th,U)Zr(Ti,Fe,Nb,Ta)(2)O-7], kassite/cafetite [CaTi2O4(OH)(2)/CaTi2O5 center dot H2O], Ti-bearing humite group minerals, thorianite, and sometimes euxenite [(Ca,U,Th,REE)(Nb,Ta,Ti)(2)(O,OH)(6)]. Stable coexistence of zircon and olivine is observed and stably coexisting titanite with olivine and/or humite-group minerals is reported here for the first time outside of carbonatites, kimberlites, or lamprophyres. Petrogenetic grids constructed for Ti- and Zr-bearing olivine/antigorite-saturated calcite-dolomite marbles show that geikielite is stable at highest pressures, followed by titanite and rutile, and that baddeleyite + diopside replaces zircon + calcite to higher pressures. The observed reaction textures are consistent with an earlier derived P-T path for the Kimi Complex. They corroborate a period of heating during decompression from 25 to 20 kbar and ca. 800 degrees C, where the assemblage olivine-diopside-spinel-rutile-zircon formed. This assemblage partially re-equilibrated during subsequent decompression and cooling, thus forming the observed reaction textures. Even though no memory of the UHP path is preserved in the accessory minerals, their reaction relationships turn out to be potentially very useful for geothermobarometry over a large range of metamorphic conditions.

AB - Rutile, titanite, and zircon formed as relatively coarse-grained accessory minerals in several samples of high-grade calcite-dolomite marble with an early ultrahigh-pressure history. These minerals decomposed to a texturally complex set of secondary minerals during subsequent stages of retrograde metamorphism. The reactions involve several generations of geikielite-ilmenite as well as zirconolite [(Ca,Th,U)Zr(Ti,Fe,Nb,Ta)(2)O-7], kassite/cafetite [CaTi2O4(OH)(2)/CaTi2O5 center dot H2O], Ti-bearing humite group minerals, thorianite, and sometimes euxenite [(Ca,U,Th,REE)(Nb,Ta,Ti)(2)(O,OH)(6)]. Stable coexistence of zircon and olivine is observed and stably coexisting titanite with olivine and/or humite-group minerals is reported here for the first time outside of carbonatites, kimberlites, or lamprophyres. Petrogenetic grids constructed for Ti- and Zr-bearing olivine/antigorite-saturated calcite-dolomite marbles show that geikielite is stable at highest pressures, followed by titanite and rutile, and that baddeleyite + diopside replaces zircon + calcite to higher pressures. The observed reaction textures are consistent with an earlier derived P-T path for the Kimi Complex. They corroborate a period of heating during decompression from 25 to 20 kbar and ca. 800 degrees C, where the assemblage olivine-diopside-spinel-rutile-zircon formed. This assemblage partially re-equilibrated during subsequent decompression and cooling, thus forming the observed reaction textures. Even though no memory of the UHP path is preserved in the accessory minerals, their reaction relationships turn out to be potentially very useful for geothermobarometry over a large range of metamorphic conditions.

U2 - 10.2138/am.2014.4710

DO - 10.2138/am.2014.4710

M3 - Article

VL - 99

SP - 1429

EP - 1448

JO - American Mineralogist

JF - American Mineralogist

SN - 0003-004X

IS - 7

ER -