Apatite: A Fingerprint for Metasomatic Processes

Harlov, Daniel E.

doi:10.2113/gselements.11.3.171

Cited by 289 publications

(146 citation statements)

References 24 publications

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“…On the Mn vs. Sr diagram, the apatites plot in the granitoid, granite pegmatite, and iron ore fields (Figure 11b). Our EPMA data are consistent with those reported from apatites from other Kiruna-type iron deposits [13,35,36,53]. The concentrations of V, Mn, and Mg have been used to discriminate IOCG-and Kiruna-type deposits [55].…”

Section: Electron Probe Microanalysis (Epma)supporting

confidence: 88%

“…Textures and chemical compositions of apatite may change due to metasomatic events over a wide range of temperatures and pressures from the mantle to surficial environments, thus making apatite an important fingerprint of metasomatic processes [13]. The three main apatite types in the Chadormalu IOA deposit show similar textural features including the occurrence of bright and dark SEM-BSE apatite spots containing monazite and xenotime inclusions.…”

Section: Textural and Mineral Chemical Evidencementioning

confidence: 99%

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Multiple Stage Ore Formation in the Chadormalu Iron Deposit, Bafq Metallogenic Province, Central Iran: Evidence from BSE Imaging and Apatite EPMA and LA-ICP-MS U-Pb Geochronology

et al. 2018

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Abstract:The Chadormalu magnetite-apatite deposit in Bafq metallogenic province, Central Iran, is hosted in the late Precambrian-lower Cambrian volcano-sedimentary rocks with sodic, calcic, and potassic alterations characteristic of iron oxide copper-gold (IOCG) and iron oxide-apatite (IOA) ore systems. Apatite occurs as scattered irregular veinlets and disseminated grains, respectively, within and in the marginal parts of the main ore-body, as well as apatite-magnetite veins in altered wall rocks. Textural evidence (SEM-BSE images) of these apatites shows primary bright, and secondary dark areas with inclusions of monazite/xenotime. The primary, monazite-free fluorapatite contains higher concentrations of Na, Si, S, and light rare earth elements (LREE). The apatite was altered by hydrothermal events that led to leaching of Na, Si, and REE + Y, and development of the dark apatite. The bright apatite yielded two U-Pb age populations, an older dominant age of 490 ± 21 Ma, similar to other iron deposits in the Bafq district and associated intrusions, and a younger age of 246 ± 17 Ma. The dark apatite yielded a U-Pb age of 437 ± 12 Ma. Our data suggest that hydrothermal magmatic fluids contributed to formation of the primary fluorapatite, and sodic and calcic alterations. The primary apatite reequilibrated with basinal brines in at least two regional extensions and basin developments in Silurian and Triassic in Central Iran.

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Section: Electron Probe Microanalysis (Epma)supporting

confidence: 88%

Section: Textural and Mineral Chemical Evidencementioning

confidence: 99%

Multiple Stage Ore Formation in the Chadormalu Iron Deposit, Bafq Metallogenic Province, Central Iran: Evidence from BSE Imaging and Apatite EPMA and LA-ICP-MS U-Pb Geochronology

et al. 2018

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“…The presence of tiny inclusions of monazite in apatite is characteristic of fluid-assisted coupled dissolution-precipitation, and suggestive of re-equilibration after grain formation (e.g. Harlov, 2011Harlov, , 2015Harlov et al, 2002Harlov et al, , 2005Harlov and Förster, 2003). Experimental results Budzyń et al, 2017) are consistent with natural observations that fluid activity is just as important as changes in P-T conditions for monazite breakdown reactions (Finger et al, 1998(Finger et al, , 2016Janots et al, 2008;Ondrejka et al, 2012Ondrejka et al, , 2016.…”

Section: Petrographic Considerations In Accessory Mineral Datingsupporting

confidence: 78%

Peak to post-peak thermal history of the Saglek Block of Labrador: A multiphase and multi-instrumental approach to geochronology

et al. 2018

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A B S T R A C TThe Saglek Block of coastal Labrador forms the western margin of the North Atlantic Craton, where Archean gneisses and granulites have been reworked during the Paleoproterozoic. Previous work has established that the block is a composite of Eoarchean to Mesoarchean protoliths metamorphosed to upper amphibolite and granulite facies at around 2.8-2.7 Ga. New in-situ microbeam dating of accessory minerals in granoblastic gneisses reveals a complex peak to post-peak thermal history. Zircon growth at ca. 3.7-3.6 Ga provides the age of formation of the tonalitic protoliths to the gneisses. Further zircon growth in syn-tectonic granitic gneiss and monazite growth in a variety of orthogneisses confirm peak metamorphic conditions at ca. 2.7 Ga, but also reveal high-temperature conditions at ca. 2.6 Ga and 2.5 Ga. The former is interpreted as the waning stages of the 2.7 Ga granulite event, whereas the latter is associated with a younger phase of granitic magmatism. In addition, apatite ages of ca. 2.2 Ga may represent either cooling associated with the 2.5 Ga event or a previously unrecognized greenschist-facies metamorphism event that predates the Torngat Orogeny.

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“…Although the selective incorporation of certain REY was considered to be crystallographically controlled [41], more recent work [42] has shown how external physiochemical parameters such as fluid composition or temperature can impact significantly on otherwise predictable patterns. Study of REY signatures in apatite has thus led to the recognition of individual signatures, or REY behaviours, attributable to specific fluid conditions within the evolution of a mineralized system [7,10]. The recent work of Migdisov et al (2016) [6] has emphasized the variability of REY behaviour brought about by the dominance of certain REY complexes such as REY-Cl and -SO 4 over others, notably REY-F.…”

Section: Apatite Mineral Chemistrymentioning

confidence: 99%

Rare Earth Element Behaviour in Apatite from the Olympic Dam Cu–U–Au–Ag Deposit, South Australia

et al. 2017

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Abstract:Apatite is a common magmatic accessory in the intrusive rocks hosting the giant~1590 Ma Olympic Dam (OD) iron-oxide copper gold (IOCG) ore system, South Australia. Moreover, hydrothermal apatite is a locally abundant mineral throughout the altered and mineralized rocks within and enclosing the deposit. Based on compositional data for zoned apatite, we evaluate whether changes in the morphology and the rare earth element and Y (REY) chemistry of apatite can be used to constrain the fluid evolution from early to late hydrothermal stages at OD. The~1.6 Ga Roxby Downs granite (RDG), host to the OD deposit, contains apatite as a magmatic accessory, locally in the high concentrations associated with mafic enclaves. Magmatic apatite commonly contains REY-poor cores and REY-enriched margins. The cores display a light rare earth element (LREE)-enriched chondrite-normalized fractionation pattern with a strong negative Eu anomaly. In contrast, later hydrothermal apatite, confined to samples where magmatic apatite has been obliterated due to advanced hematite-sericite alteration, displays a conspicuous, convex, middle rare earth element (MREE)-enriched pattern with a weak negative Eu anomaly. Such grains contain abundant inclusions of florencite and sericite. Within high-grade bornite ores from the deposit, apatite displays an extremely highly MREE-enriched chondrite-normalized fractionation trend with a positive Eu anomaly. Concentrations of U and Th in apatite mimic the behaviour of ∑REY and are richest in magmatic apatite hosted by RDG and the hydrothermal rims surrounding them. The shift from characteristic LREE-enriched magmatic and early hydrothermal apatite to later hydrothermal apatite displaying marked MREE-enriched trends (with lower U, Th, Pb and ∑REY concentrations) reflects the magmatic to hydrothermal transition. Additionally, the strong positive Eu anomaly in the MREE-enriched trends of apatite in high-grade bornite ores are attributable to alkaline fluid conditions.

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Apatite: A Fingerprint for Metasomatic Processes

Cited by 289 publications

References 24 publications

Multiple Stage Ore Formation in the Chadormalu Iron Deposit, Bafq Metallogenic Province, Central Iran: Evidence from BSE Imaging and Apatite EPMA and LA-ICP-MS U-Pb Geochronology

Multiple Stage Ore Formation in the Chadormalu Iron Deposit, Bafq Metallogenic Province, Central Iran: Evidence from BSE Imaging and Apatite EPMA and LA-ICP-MS U-Pb Geochronology

Peak to post-peak thermal history of the Saglek Block of Labrador: A multiphase and multi-instrumental approach to geochronology

Rare Earth Element Behaviour in Apatite from the Olympic Dam Cu–U–Au–Ag Deposit, South Australia

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