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

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F17%3A00096233" target="_blank" >RIV/00216224:14310/17:00096233 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1016/j.oregeorev.2016.09.017" target="_blank" >http://dx.doi.org/10.1016/j.oregeorev.2016.09.017</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.oregeorev.2016.09.017" target="_blank" >10.1016/j.oregeorev.2016.09.017</a>

Result language

angličtina

Original language name

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

Original language description

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 &gt;=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.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10500 - Earth and related environmental sciences

Project

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Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2017

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Ore geology reviews

ISSN

0169-1368

e-ISSN

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Volume of the periodical

80

Issue of the periodical within the volume

January

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

20

Pages from-to

1072-1091

UT code for WoS article

000387625800059

EID of the result in the Scopus database

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