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; Paquette, Jean‐Louis; Huiraiová, Monika; Slobodník, Marek; Hvožďara, Pavel; Siegfried, Peter; Gajdošová, Michaela; Milovská, Stanislava

doi:10.1016/j.oregeorev.2016.09.017

Cited by 14 publications

(11 citation statements)

References 63 publications

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Section: Texture Characteristics Of Monazitementioning

confidence: 99%

“…In thin sections, monazite appears in a variety of colors, from colorless to yellowish, greenish, and brownish [9,10] (e.g., Figure 2c,d). More commonly, it is the product of metasomatic/hydrothermal alteration of the primary mineral assemblage within the carbonatite (e.g., apatite) or occurs along the fractures of the matrix carbonate as interstitial fillings or form veinlets or, which appears as fine-grained polycrystalline clusters (e.g., Figure 2e,f, or Figure 3) [11].…”

Section: Texture Characteristics Of Monazitementioning

confidence: 99%

“…The secondary monazite commonly shares mineral associations with apatite, barite, fluorite, hematite, quartz, sulfide, bastnasite, xenotime, feldspar, titanite, synchysite, goyazite, and strontianite. Some monazite shows an association with K-feldspar [12,13] (e.g., Figure 2h), or is intergrown with albite [9] (e.g., Evate). The monazite aggregates display a close association with molybdenite in the Huanglongpu carbonatite (Figure 2i).…”

Section: Texture Characteristics Of Monazitementioning

confidence: 99%

“…Though monazite can survive at temperatures much higher than 750 °C, in carbonatite it is restricted to temperatures lower than 750 °C [20]. [21]; (b) disseminated monazite within dolomite marble from Bayan Obo, Inner Mongolia, China; (c) yellow monazite crystals crystallized on the rim of albite matrix from Evate, Mozambique [9]; (d) green monazite occurs as disseminations in the strontianite matrix in Kangankunde, Malawi [10]; (e) BSE image of anhedral monazite in carbonatite from Mountain Pass, the United States [21]; (f) monazite in strongly foliated dolomite carbonatite with quartz laminae from the Cummins Range carbonatite, Australia [22]; (g) monazite net of veinlets in dolomite from Seligdar apatite deposit, Russia [11]; (h) backscattered electron image showing a vug in dolomite filled with potassium feldspar and monazite from the Wideeda carbonatite, Canada [12]; (i) monazite aggregates together with molybdenite in the calcite carbonatite from Huanglongpu, China; (j) euhedral monazite core with small monazite grains in the cracked and resorbed rim from the Hongcheon complex, Korea [14]; (k,l) typical monazite-pyrochlore-crandallite ore in the Tomtor deposit (Russia); and relict pyrochlore crystal in monazite and goyazite as colloform globular segregations in a colloform goethite aggregate [23]. Ab = albite; Ank = ankerite; Ap = apatite; Mnz = monazite; Dol = dolomite; [21]; (b) disseminated monazite within dolomite marble from Bayan Obo, Inner Mongolia, China; (c) yellow monazite crystals crystallized on the rim of albite matrix from Evate, Mozambique [9]; (d) green monazite occurs as disseminations in the strontianite matrix in Kangankunde, Malawi [10]; (e) BSE image of anhedral monazite in carbonatite from Mountain Pass, the United States [21]; (f) monazite in strongly foliated dolomite carbonatite with quartz laminae from the Cummins Range carbonatite, Australia [22]; (g) monazite net of veinlets in dolomite from Seligdar apatite deposit, Russia [11]; (h) backscattered electron image showing a vug in dolomite filled with potassium feldspar and monazite from the Wideeda carbonatite, Canada [12]; (i) monazite aggregates together with molybdenite in the calcite carbonatite from Huanglongpu, China; (j) euhedral monazite core with small monazite grains in the cracked and resorbed rim from the Hongcheon complex, Korea [14]; (k,l) typical monazite-pyrochlore-crandallite ore in the Tomtor deposit (Russia); and relict pyrochlore crystal in monazite and goyazite as colloform globular segregations in a colloform goethite aggregate [23].…”

Section: Texture Characteristics Of Monazitementioning

confidence: 99%

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Geochemistry of Monazite within Carbonatite Related REE Deposits

et al. 2017

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Approximately >50% of global rare earth element (REE) resources are hosted by carbonatite related deposits, of which monazite is one of the most important REE minerals. Monazite dominates more than 30 carbonatite-related REE deposits around the world, including currently exploited mineralization at Bayan Obo and Mount Weld. These deposits are widely distributed across all continents, except Antarctica. Though rare, monazite occurs as the primary mineral in carbonatite, and mostly presents as a secondary mineral that has a strong association with apatite. It can partially or completely replace thin or thick overgrowth apatite, depending on the availability of REE. Other mineral phases that usually crystallize together with monazite include barite, fluorite, xenotime, sulfide, and quartz in a carbonate matrix (e.g., dolomite, calcite). This review of monazite geochemistry within carbonatite-related REE deposits aims to provide information regarding the use of monazite as a geochemical indicator to track the formation history of the REE deposits and also supply additional information for the beneficiation of monazite. The chemical compositions of monazite are highly variable, and Ce-monazite is the dominant solid solution in carbonatite related deposits. Most monazite displays steep fractionation from La to Lu, absent of either Eu or Ce anomalies in the chondrite normalized REE plot. The other significant components are huttonite and cheratite. Some rare sulfur-bearing monazite is also identified with an SO 3 content up to 4 wt %. A 147 Sm/ 144 Nd ratio with an average~0.071 for monazite within carbonatite-related ores is similar to that of their host rocks (~0.065), and is the lowest among all types of REE deposits. Sm/Nd variation of monazite from a single complex reflects the differentiation stage of magma, which decreases from early to late. Based on the differences of Nd and Sr abundances, Nd isotopic composition for monazite can be used to track the magma source, whereas Sr isotopic composition records the signatures of the fluid source. Th-(U)-Pb age determination of the secondary monazite records variable thermal or metasomatic disturbances, and careful geochronological interpretation should be brought forward combined with other lines of evidence. ThO 2 is the most difficult contamination in the beneficiation of monazite, luckily, the ThO 2 content of monazite within carbonatite is generally low (<2 wt %).

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Section: Texture Characteristics Of Monazitementioning

confidence: 99%

Section: Texture Characteristics Of Monazitementioning

confidence: 99%

Section: Texture Characteristics Of Monazitementioning

confidence: 99%

Section: Texture Characteristics Of Monazitementioning

confidence: 99%

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Geochemistry of Monazite within Carbonatite Related REE Deposits

et al. 2017

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“…Dolomite inclusions oriented parallel to the c‐axis of apatite have been found in UHP carbonate‐rich rocks in the Tromsø Nappe of the Scandinavian Caledonides in Norway (Broska et al, ), but the oriented calcite inclusions found in apatite of this study, as far as we know, have never been documented for any UHP rock. It should be noted that oriented mineral inclusions like monazite and pyrrhotite have been also reported frequently for apatite formed at non‐UHP and even low pressure conditions (e.g., Hansen & Harlov, ; Harlov et al, ; Harlov & Förster, ; Hurai et al, ; Janots et al, ; Pan, ; Pan et al, ; Rajesh et al, ; Xing & Wang, ). While these inclusions have been interpreted as products resulting from an “exsolution” process during decompression of UHP rocks (Liang et al, ; Sun et al, ; Zhang & Liou, ; Zhu & Massonne, , ), they have been more commonly interpreted as products of metasomatic reactions (e.g., Broska et al, ; Harlov et al, , ; Harlov & Förster, ; Harlov & Förster, ; Janots et al, ; Liu, Massonne, Wu, et al, ; Pan, ; Pan et al, ; Rajesh et al, ).…”

Section: Discussionmentioning

confidence: 93%

High‐Pressure Fluid‐Rock Interaction and Mass Transfer During Exhumation of Deeply Subducted Rocks: Insights From an Eclogite‐Vein System in the Ultrahigh‐Pressure Terrane of the Dabie Shan, China

Liu

Massonne

Harlov

et al. 2019

Geochem Geophys Geosyst

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A petrological study was performed on an eclogite-vein system from the Dabie ultrahigh-pressure terrane by focusing on high-pressure (HP) fluid-rock interaction and mass transfer during exhumation. The veins comprise mainly garnet and quartz and resulted from a HP leaching process along fractures in the eclogite during exhumation. Relict peak garnet, phengite, and apatite in this rock system were altered by HP fluids forming characteristic compositional zonings. Zoned garnet in the eclogite records an isothermal exhumation from 3.3 GPa and 665-680°C. Partial dissolution of garnet and a back incorporation of Mn-heavy rare earth element (REE)-Y increased the content of these elements in the altered garnet zone in the veins. Altered phengite is characterized by a Ba-rich rim. Fluid-aided alteration reduced the light REE (LREE) contents and produced oriented monazite, calcite, and pyrrhotite inclusions within apatite, reflecting mobilization and redistribution of LREEs, CO 3 2− , Fe, and S between these minerals. The active HP fluid is proposed to have been a Si-Al-Na-Ba-rich aqueous fluid, as indicated by sodic plagioclase rims around various eclogitic minerals and by the altered phengite composition. Mass balance calculations reveal that LREEs, middle REEs, and Zr-Hf-Th-U were added to and Li, large ion lithophile elements, and Ti-Nb were removed from the quartz-garnet veins, requiring a high fluid flux. These findings shed new light on the nature and behavior of HP fluids and highlight their key role in resetting mineral chemistry and mass transfer in subduction zone metamorphic environments. . (2019). High-pressure fluid-rock interaction and mass transfer during exhumation of deeply subducted rocks: insights from an eclogite-vein system in the ultrahigh-pressure terrane of the Dabie The Dabie-Sulu orogenic belt in east-central China is considered to be one of the largest UHP terranes on Earth. This belt resulted from the Triassic continental collision between the North China and South China blocks (Ernst et al., 2007;Li et al., 1993;Zhang et al., 2009). It is separated into the eastern Sulu terrane and the western Dabie terrane by the sinistral Tanlu strike-slip fault. The western part of the Dabie terrane is further truncated by the Shangma fault and known as the Hongan terrane (Figure 1a).Several large-scale EW trending faults divide the Dabie terrane into five major lithotectonic units with different metamorphic histories (Hacker et al., 2000;Zheng et al., 2005). From north to south, these units are (1) the Beihuaiyang greenschist-facies unit made up of low-grade metasedimentary and metaigneous rocks that are overlain by Jurassic-Cretaceous sedimentary and volcanic rocks; (2) the North Dabie high-T granulite-facies unit composed of typical amphibolite-to granulite-facies rocks, migmatitic gneisses, and minor mafic to ultramafic rocks; (3) the Central Dabie medium-T/UHP eclogite-facies unit including abundant orthogneisses and paragneisses that enclose subordinate bodies of coesite-bearing eclogite, pure to imp...

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Formation of magnetite-(apatite) systems by crystallizing ultrabasic iron-rich melts and slag separation

Tornos,

Hanchar,

Steele-MacInnis

et al. 2023

Miner Deposita

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Magnetite-(apatite) ore deposits are interpreted as being formed by the crystallization of iron-rich ultrabasic melts, dominantly generated by the interaction of silicate melts with oxidized P-F-SO4-bearing sedimentary rocks. This hypothesis is supported by geologic evidence, experimental studies, numerical modeling, stable and radiogenic isotope geochemistry, mineralogy, and melt- and mineral-inclusion data. Assimilation of crustal rocks during ascent promotes separation from a silicate magma of Fe-rich, Si-Al-poor melts with low solidus temperatures and viscosities, allowing coalescence, migration, and emplacement at deep to subaerial crustal environments. When the iron-rich melt attains neutral buoyancy, fractional crystallization leads to melt immiscibility similar to that observed in industrial blast furnaces, which promotes separation of massive magnetite ore overlain by different types of “slag” containing actinolite or diopside ± phosphates ± magnetite ± feldspar ± anhydrite ± scapolite, commonly enriched in high field strength elements. The mineralogy and morphology of this iron-depleted cap strongly depend on the depth of emplacement and composition of the iron-rich magma. Most of these systems exhibit high oxygen fugacity, which inhibits the precipitation of significant sulfide mineralization. The initially high fO2 of these systems also promotes the formation of low-Ti (< 1 wt%) magnetite: Ti acts as an incompatible component and is enriched in the iron-poor caps and in the hydrothermal aureole. High fluid-phase pressures produced during massive crystallization of magnetite from the melt further facilitate the exsolution of magmatic-hydrothermal fluids responsible for the formation of aureoles of alkali-calcic-iron alteration with hydrothermal replacement-style iron mineralization. On the whole, these systems are dramatically different from the magmatic-hydrothermal systems related to intermediate to felsic igneous rocks; they are more akin to carbonatite and other ultramafic rocks.

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

Cited by 14 publications

References 63 publications

Geochemistry of Monazite within Carbonatite Related REE Deposits

Geochemistry of Monazite within Carbonatite Related REE Deposits

High‐Pressure Fluid‐Rock Interaction and Mass Transfer During Exhumation of Deeply Subducted Rocks: Insights From an Eclogite‐Vein System in the Ultrahigh‐Pressure Terrane of the Dabie Shan, China

Formation of magnetite-(apatite) systems by crystallizing ultrabasic iron-rich melts and slag separation

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