J 2017

New insights into the origin of the Evate apatite-iron oxide-carbonate deposit, Northeastern Mozambique, constrained by mineralogy, textures, thermochronometry, and fluid inclusions

HURAI, Vratislav, Jean-Louis PAQUETTE, Monika HUIRAIOVÁ, Marek SLOBODNÍK, Pavel HVOŽĎARA et. al.

Základní údaje

Originální název

New insights into the origin of the Evate apatite-iron oxide-carbonate deposit, Northeastern Mozambique, constrained by mineralogy, textures, thermochronometry, and fluid inclusions

Autoři

HURAI, Vratislav (703 Slovensko), Jean-Louis PAQUETTE (250 Francie), Monika HUIRAIOVÁ (703 Slovensko), Marek SLOBODNÍK (203 Česká republika, garant, domácí), Pavel HVOŽĎARA (703 Slovensko), Peter SIEGFRIED (528 Nizozemské království), Michaela GAJDOŠOVÁ (703 Slovensko) a Stanislava MILOVSKÁ (703 Slovensko)

Vydání

Ore geology reviews, Amsterdam, ELSEVIER SCIENCE BV, 2017, 0169-1368

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10500 1.5. Earth and related environmental sciences

Stát vydavatele

Nizozemské království

Utajení

není předmětem státního či obchodního tajemství

Odkazy

Impakt faktor

Impact factor: 3.993

Kód RIV

RIV/00216224:14310/17:00096233

Organizační jednotka

Přírodovědecká fakulta

DOI

UT WoS

000387625800059

Klíčová slova anglicky

Carbonatite; Apatite; East-African orogen; U-Th-Pb dating; Fluid inclusions; Evate deposit

Štítky

Příznaky

Mezinárodní význam, Recenzováno
Změněno: 9. 4. 2018 16:20, Ing. Nicole Zrilić

Anotace

V originále

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.