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@article{1374320,
author = {Hurai, Vratislav and Paquette, JeanandLouis and Huiraiová, Monika and Slobodník, Marek and Hvožďara, Pavel and Siegfried, Peter and Gajdošová, Michaela and Milovská, Stanislava},
article_location = {Amsterdam},
article_number = {January},
doi = {http://dx.doi.org/10.1016/j.oregeorev.2016.09.017},
keywords = {Carbonatite; Apatite; East-African orogen; U-Th-Pb dating; Fluid inclusions; Evate deposit},
language = {eng},
issn = {0169-1368},
journal = {Ore geology reviews},
title = {New insights into the origin of the Evate apatite-iron oxide-carbonate deposit, Northeastern Mozambique, constrained by mineralogy, textures, thermochronometry, and fluid inclusions},
url = {http://dx.doi.org/10.1016/j.oregeorev.2016.09.017},
volume = {80},
year = {2017}
}
TY - JOUR
ID - 1374320
AU - Hurai, Vratislav - Paquette, Jean-Louis - Huiraiová, Monika - Slobodník, Marek - Hvožďara, Pavel - Siegfried, Peter - Gajdošová, Michaela - Milovská, Stanislava
PY - 2017
TI - New insights into the origin of the Evate apatite-iron oxide-carbonate deposit, Northeastern Mozambique, constrained by mineralogy, textures, thermochronometry, and fluid inclusions
JF - Ore geology reviews
VL - 80
IS - January
SP - 1072-1091
EP - 1072-1091
PB - ELSEVIER SCIENCE BV
SN - 01691368
KW - Carbonatite
KW - Apatite
KW - East-African orogen
KW - U-Th-Pb dating
KW - Fluid inclusions
KW - Evate deposit
UR - http://dx.doi.org/10.1016/j.oregeorev.2016.09.017
N2 - The Evate deposit represents the largest resource of apatite in south-east Africa (155 Mt. ore grading 9.3 wt.% P2O5) accumulated in up to 100 m thick magnetite-carbonate-apatite horizons conformable to the granulitic gneiss of the Monapo Klippe. Baddeleyite and zircon from early iron-oxide (magnetite, geikielite, spinel), apatite- and forsterite-bearing rocks have been dated to 590±6 Ma using the LA-ICPMS U-Pb method, whereas monazites from anhydrite-apatite-carbonate rocks show a concordant U-Pb-Th age corresponding to 449 ± 2 Ma. Temperatures inferred fromcalcite-dolomite solvus data and graphite structural ordering span the interval from >=815 to 276 °C. Primary and secondary fluid inclusions in apatite document calciocarbonatite melts associated with early apatite, and CO2-bearing sulfate-chloride brines progressively dilutedwith low-salinity, probably meteoric waters, towards ultimate stages of the deposit formation. The calciocarbonatite melts have initially coexisted with liquid nitrogen and later with sulfate-chloride brines mixed with N2± CO2 gas. Crystallization of spinel around baddeleyite by the mechanismof Ostwald ripening, nucleation of graphite spherules along pyrrhotite-carbonate boundaries, the occurrence of molybdenite, baddeleyite-to-zircon transformation, and high crystallization temperatures inferred from graphite structural ordering and calcite-dolomite thermometry suggest a magmatic origin of the early mineral assemblages. In contrast, microthermometric characteristics of primary aqueous inclusions in the late apatite and the presence of zeolites (thomsonite-Ca, mezolite) is diagnostic of a low-temperature hydrothermal crystallization. Formation of the early magnetite-apatite-forsterite assemblage is thought to be coeval with mafic alkalic intrusions of the Mazerapane Suite superimposed on the granulite facies metamorphism of the Monapo Klippe. The low-temperature, anhydrite-bearing mineralization was associated with the massive circulation of sulfate-rich brines along fractures activated during the Late Cambrian-Ordovician extension. Origin of the sulfate-rich brines may be genetically related either with the magmatic-hydrothermal differentiation, or with the remobilization of crustal evaporites.
ER -
HURAI, Vratislav, Jean-Louis PAQUETTE, Monika HUIRAIOVÁ, Marek SLOBODNÍK, Pavel HVOŽĎARA, Peter SIEGFRIED, Michaela GAJDOŠOVÁ a Stanislava MILOVSKÁ. New insights into the origin of the Evate apatite-iron oxide-carbonate deposit, Northeastern Mozambique, constrained by mineralogy, textures, thermochronometry, and fluid inclusions. \textit{Ore geology reviews}. Amsterdam: ELSEVIER SCIENCE BV, 2017, roč.~80, January, s.~1072-1091. ISSN~0169-1368. Dostupné z: https://dx.doi.org/10.1016/j.oregeorev.2016.09.017.
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