Element Partitioning between Immiscible Carbonatite and Silicate Melts for Dry and H2O-bearing Systems at 1–3 GPa

Martin, Lukas H.J.; Schmidt, Max W.; Mattsson, Hannes B.; Guenther, D.

doi:10.1093/petrology/egt048

Cited by 164 publications

(117 citation statements)

References 65 publications

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“…They explain that trace element patterns derived from element partitioning models, and experimental data from Veksler et al (2012), are suggestive of strong partitioning of ree into the silicate phase in immiscible carbonate-silicate systems. These findings are consistent with experimental data of Martin et al (2013), who further report that increased ree partitioning into a carbonatite melt can occur with higher SiO 2 contents of the immiscible silicate melt. The presence of water also increases ree partition coefficients for a carbonatite melt in a carbonatite-silicate system (Martin et al 2013).…”

Section: Source Magmasupporting

confidence: 93%

“…Chondrite-normalized Y values are similar to those of Ho as often reported, due to ion size and charge similarity (Wall et al 2008). It is important to note here that current understanding of partitioning behaviours of ree in zircon-carbonatite systems are limited, but a few studies have shown that they are not equivalent to those in zircon-silicate systems (Blundy and Dalton 2000;Veksler et al 2012, Martin et al 2013). a full interpretation of the low lree signatures in the magmatic core zircon therefore remains open.…”

Section: Zircon Compositionssupporting

confidence: 76%

“…Trace element compositions in zircons from a variety of igneous rock types are listed by Belousova et al (2002) and evaluated for their use as source indicators. Partitioning behaviour of trace elements between zircon and magmas associated with carbonatitic systems remains poorly understood, as no experimental data have been produced, and other indicators, relating to ree partitioning between immiscible silicate-carbonatite melts, are limited (Blundy and Dalton 2000;Blundy and Wood 2003;Chakhmouradian and Williams 2004;Chakhmouradian 2006;Chakhmouradian and Zaitsev 2012;rodionov et al 2012;Veksler et al 2012;Martin et al 2013). However, Chakhmouradian (2006) states that partitioning of the high-field-strength elements (HFSe) that include the Hree are controlled by charge constraints relating to the crystallographic environment, and in general, carbonatitic HFSe are considered to originate from partial melting of metasomatized mantle sources (Chakhmouradian 2006;Blundy and Dalton 2000).…”

Section: Introductionmentioning

confidence: 99%

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Zircon from the East Orebody of the Bayan Obo Fe–Nb–REE deposit, China, and SHRIMP ages for carbonatite-related magmatism and REE mineralization events

Campbell

Compston

Sircombe

et al. 2014

Contrib Mineral Petrol

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match closely with those from the Mud Tank and Kovdor carbonatitic zircons. Increased Hree in rims ((lu/gd) n 43-112) relative to cores ((lu/gd) n 6-7.5) and the localized presence of xenotime are attributable to reactive, mineralizing fluid compositions enriched in Y, ree and P. Cathodoluminescence further reveals Hree fractionation in rims, evidenced by a narrow-band er 3+ emission at 405 nm. The extreme depletion of U in core and rim zircon is characteristic for this mineral deposit and is indicative of a persistent common source. U depletion is also a characteristic for zircons from carbonatitic or kimberlitic systems.232 Pb (SHrIMP II) geochronological data reveal the age of zircon cores as 1,325 ± 60 Ma and a rimalteration event as 455.6 ± 28.27 Ma. The combined findings are consistent with a protolithic igneous origin for zircon cores, from a period of intrusive, alkaline-carbonatitic magmatism. Fluid processes responsible for the ree-nb mineralizations affected zircon rim growth and degradation during the widely reported Caledonian events, providing a new example in a localized context of Hree enrichment processes.

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Section: Source Magmasupporting

confidence: 93%

Section: Zircon Compositionssupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

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Zircon from the East Orebody of the Bayan Obo Fe–Nb–REE deposit, China, and SHRIMP ages for carbonatite-related magmatism and REE mineralization events

Campbell

Compston

Sircombe

et al. 2014

Contrib Mineral Petrol

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“…Experiments that constrain the maximum extend of the miscibility gap are from Freestone and Hamilton (1980), Kjarsgaard (1998), Brooker andKjarsgaard (2011), andMartin et al (2013). Note that in earlier experiments rounded calcite had been interpreted as melt, however, this has been corrected by the original authors.…”

Section: Carbonatite -Silicate Melt Immiscibilitymentioning

confidence: 99%

“…Note that in earlier experiments rounded calcite had been interpreted as melt, however, this has been corrected by the original authors. Alkali-poor carbonatite quench interstitial to silicate minerals has also been reported as immiscible melt compositions, but experiments on the reported conjugated melt pairs have shown that the carbonatites were not immiscible melts, hence the alkalipoor carbonatite quench analyses did not represent melt compositions (Kjarsgaard, 1998;Martin et al, 2013).…”

Section: Carbonatite -Silicate Melt Immiscibilitymentioning

confidence: 99%

Carbonatites in oceanic hotspots

Schmidt¹,

Weidendorfer

2018

Geology

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SUPPLEMENTARY MATERIAL METHODSData were compiled from the pre-sorted georoc database ocean island files (http://georoc.mpchmainz.gwdg.de/georoc/). Hot spots such as Aetna or Samoa with geotectonically complex situations and possible direct interference with subduction were avoided; otherwise we used those with sufficiently large data sets. Each file was filtered for analyses with 95-101.5 wt% totals, samples outside this range or listed as altered were excluded. All bulk rock compositions are then normalized to 100 wt% total on a volatile free basis with all Fe as FeO.The histogram of total alkalis for extrusives shows a clear cut-off to <1.4 wt% K 2 O+Na 2 O. Of e.g. 9'000 extrusives of the Hawaiian hotspot only 24 are below this values, these are essentially from three publications (without geographical coherence), suggesting that these rocks were altered or possibly have an analytical problem; this is corroborated by a K 2 O/Na 2 O ranging from 0.01 to 2 for these 24 samples. We have hence excluded all rocks with <1.4 wt% Na 2 O+K 2 O. Similarly, we did not accept trace element concentrations measured by XRF that are below 5-15 ppm (depending on the element).Within each ocean island, rocks were sorted for (i) Those with X Mg >0.77 and/or Ni>650 ppm, this group is mostly olivine cumulative and was excluded from all plots. (ii) Primitive melts were designated when X Mg =0.77-0.65, which corresponds to equilibrium with olivine of Fo 92-88 at 5-15 mol% Fe 3+ (of Fe tot ), and Ni=150-650 ppm, corresponding to roughly 2000-4500 ppm Ni in mantle olivine (note that the K D olivine/melt of Ni strongly depends on temperature, hence this range is chosen rather large). (iii) To enlarge the dataset, rocks with 0.55100 analyses were retained, the dataset sorted for the above criteria contains 124-198 analyses for Pitcairn, Ascension, St. Helena and Tristan da Cunha; 242-331 for GSA Data Repository 2018136

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Melting phase relations of model carbonated peridotite from 2 to 3 GPa in the system CaO‐MgO‐Al₂O₃‐SiO₂‐CO₂ and further indication of possible unmixing between carbonatite and silicate liquids

et al. 2014

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Melting phase relations of model carbonated peridotite in the system CaO-MgO-Al 2 O 3 -SiO 2 -CO 2 from 2 to 3 GPa are reported. Experimentally produced melts, which are model carbonatites, with approximately 36-40 wt % CaO, 12-17 wt % MgO, 0.2-1.5 wt % Al 2 O 3 , 1-4 wt % SiO 2 , and 40-42 wt % CO 2 (carbon dioxide) are present at all pressures investigated. At 2.8 and 3 GPa, carbonatitic melts are seen experimentally at temperatures that are very close to the vapor-free (CO 2 ) peridotite solidus and are found in equilibrium with forsterite, orthopyroxene, clinopyroxene, and garnet. Solidus phase relations with isobaric and pressure-temperature invariant points, defining the so-called carbonated peridotite solidus ledge, are also reported from 2.1 to 3 GPa. A divariant region exists from 2 to 2.6 GPa wherein two, compositionally different melts are present. In this region, these two melts, carbonatitic and silicate in composition, coexist with crystalline phase assemblage and free vapor. The silicate liquid has approximately 30-48 wt % SiO 2 and approximately 6 to 20 wt % of dissolved CO 2 . The presence of carbonatitic and silicate liquids is interpreted to be due to liquid immiscibility. On the basis of melting phase relations reported here, we conclude that (a) the ledge is a feature along which model carbonatitic liquids are produced by reaction of silicates and CO 2 vapor and (b) alkali-free carbonatites and silicate melts can form through melt unmixing at depths of~60-80 km in the Earth's mantle.

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Element Partitioning between Immiscible Carbonatite and Silicate Melts for Dry and H2O-bearing Systems at 1–3 GPa

Cited by 164 publications

References 65 publications

Zircon from the East Orebody of the Bayan Obo Fe–Nb–REE deposit, China, and SHRIMP ages for carbonatite-related magmatism and REE mineralization events

Zircon from the East Orebody of the Bayan Obo Fe–Nb–REE deposit, China, and SHRIMP ages for carbonatite-related magmatism and REE mineralization events

Carbonatites in oceanic hotspots

Melting phase relations of model carbonated peridotite from 2 to 3 GPa in the system CaO‐MgO‐Al₂O₃‐SiO₂‐CO₂ and further indication of possible unmixing between carbonatite and silicate liquids

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Element Partitioning between Immiscible Carbonatite and Silicate Melts for Dry and H2O-bearing Systems at 1–3 GPa

Cited by 164 publications

References 65 publications

Zircon from the East Orebody of the Bayan Obo Fe–Nb–REE deposit, China, and SHRIMP ages for carbonatite-related magmatism and REE mineralization events

Zircon from the East Orebody of the Bayan Obo Fe–Nb–REE deposit, China, and SHRIMP ages for carbonatite-related magmatism and REE mineralization events

Carbonatites in oceanic hotspots

Melting phase relations of model carbonated peridotite from 2 to 3 GPa in the system CaO‐MgO‐Al2O3‐SiO2‐CO2 and further indication of possible unmixing between carbonatite and silicate liquids

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Melting phase relations of model carbonated peridotite from 2 to 3 GPa in the system CaO‐MgO‐Al₂O₃‐SiO₂‐CO₂ and further indication of possible unmixing between carbonatite and silicate liquids