Clinopyroxene REE distribution coefficients for shergottites: The REE content of the Shergotty melt

McKay, G.; Wagstaff, J.; Yang, Sui-Qin

doi:10.1016/0016-7037(86)90374-1

Cited by 166 publications

(74 citation statements)

References 21 publications

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“…The partitioning behavior of REE between the fluid and clinopyroxene or garnet has not yet been known. The data on the REE partitioning between melt and the minerals (Schnetzler and Philpotts, 1970;McKay et al, 1986) imply that clinopyroxene favors the MREEs-HREEs relative to the LREEs, garnet prefers the HREEs, and garnet has higher partition coefficients than clinopyroxene. Because the partition behavior of each mineral is probably invariable and the REE patterns of limestone do not vary, the REE patterns and features of garnet or clinopyroxene different from those of limestone are most likely derived from the original hydrothermal fluids.…”

Section: Rees Of Skarn and Ore Calcite As An Indicator To Origins mentioning

confidence: 97%

Rare Earth Elements as an Indicator to Origins of Skarn Deposits: Examples of the Kamioka Zn‐Pb and Yoshiwara‐Sannotake Cu(–Fe) Deposits in Japan

Kato

1999

Resource Geology

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: Systematic data of rare earth elements (REEs) are presented in order to put some constraints on the origin of hydrothermal fluids responsible for two contrastive skarn deposits in Japan; the Kamioka Zn‐Pb and Yoshiwara‐Sannotake Cu(‐Fe) deposits. Carbon and oxygen isotopic studies have demonstrated that the hydrothermal fluids responsible for the Kamioka Zn‐Pb deposits are of meteoric water origin whereas those for the Yoshiwara‐Sannotake Cu(‐Fe) deposits are of magmatic water origin. The REE abundances of epidote skarn derived from aluminous rocks, garnet and clinopyroxene in calcic exoskarn derived from limestone, and interstitial calcite associated with sulfide minerals were determined for these contrastive skarn deposits by inductively‐coupled plasma mass spectrometry (ICP‐MS). A significant difference in the REE concentrations is not found between epidote skarn and aluminous original rock (plagioclase‐clinopyroxene rock, called Inishi rock) from the Kamioka Zn‐Pb deposits, indicating that the REEs are generally immobile during the formation of epidote skarn, and that the REE concentrations of the hydrothermal fluid are considerably low relative to the aluminous original rock. In contrast, the epidote skarn exhibits enrichment of Eu with increasing total REE concentrations relative to the aluminous original rock (quartz diorite) in the Yoshiwara‐Sannotake Cu(‐Fe) deposits, implying a contribution of magmatic fluid derived from granitoids during the skarn formation. Limestone generally has much lower REE concentrations related to surrounding aluminous rocks, and thus the REE concentrations of garnet and clinopyroxene in calcic exoskarn, originated from limestone, are variable due to the interaction with the hydrothermal fluids. The chondrite‐normalized REE patterns of garnet, clinopyroxene, and interstitial calcite exactly provide useful information on origins of hydrothermal fluids. The REE patterns of these minerals from the Kamioka Zn‐Pb deposits show lower (Pr/Yb)cn ratios, and negative Ce and Eu anomalies inherited from limestone with the decrease of This suggests that the hydrothermal fluids responsible for the Kamioka Zn‐Pb deposits were depleted in REEs, and were not magmatic water in origin, but presumably meteoric one. In striking contrast, the REE patterns of exoskarn minerals and calcite from the Yoshiwara‐Sannotake Cu(‐Fe) deposits exhibit a positive Eu anomaly, and high (Pr/Yb)cn ratios with the considerable increase of σREE and the disappearance of negative Ce anomaly, implying that the fluids were dominantly of magmatic origin. The REE indices are very likely to be an excellent indicator to origins of the skarn deposits.

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Section: Rees Of Skarn and Ore Calcite As An Indicator To Origins mentioning

confidence: 97%

Rare Earth Elements as an Indicator to Origins of Skarn Deposits: Examples of the Kamioka Zn‐Pb and Yoshiwara‐Sannotake Cu(–Fe) Deposits in Japan

Kato

1999

Resource Geology

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“…Constraints on the influence of fO 2 and other factors on D(Cr) px are available from a review by Irving (1978) as well as many more recent studies, for example, Barnes (1986), Bartels and Grove (1991), and Auwera et al (2000). Probably the most relevant data are those of McKay et al (1986) for Shergotty-like compositions at QFM, which indicate that D(Cr) px is ~10 for augite and roughly 8 for pigeonite. In fact, these D(Cr) px agree better with our inferences for the "real" D(Cr) px (based on Fig.…”

Section: Inferences Concerning Oxygen Fugacitymentioning

confidence: 99%

“…Thus, if anything, Los Angeles' extraordinarily low mg probably tended to reduce D(Cr) px . The unusually high augite/ pigeonite ratio of Los Angeles presumably helped to raise D(Cr) px , but in general (and most pertinently, in the data set of McKay et al 1986), the difference between D(Cr) pigeonite and D(Cr) augite does not appear nearly great enough (considering that the augite/pigeonite ratio was only slightly higher in Los Angeles) to account for the much higher D(Cr) px that apparently prevailed during crystallization of Los Angeles versus QUE 94201, Shergotty, and Zagami (Fig. 8).…”

Section: Inferences Concerning Oxygen Fugacitymentioning

confidence: 99%

Los Angeles: A tale of two stones

Warren¹,

Greenwood

Rubin³

2004

Meteorit & Planetary Scien

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Abstract-We compare and contrast the mineralogy and petrology of the 2 stones of the extremely ferroan and Cr-poor martian meteorite, Los Angeles. The 2 stones are similar in many characteristics, strongly suggesting that they originated from a single flow or shallow intrusion. However, stone 2 is more ferroan and enriched in late-stage materials than its larger, and more widely studied, sibling. Stone 2 has a far higher abundance (~25 vol%) than stone 1 (10 vol%) of combined "opaques," meaning not only conventional opaque minerals but also, and more abundantly, fine-grained symplectitic intergrowths of fayalite + ferroan augite + silica (interpreted as pyroxferroite breakdown material, PBM). The bulk composition of the PBM is close to that of stoichiometric pyroxferroite, with roughly 45 wt% FeO. Extensive zonation within the pyroxenes of both stones is consistent with origin by closed-system fractional crystallization of the parent basaltic melt(s). However, the compositional and modal disparity between the two stones suggests that they formed in an environment where at least mild multi-cm-scale differentiation occurred. Probably, in both stones, crystallization began from similar melts with mg ~27-28 mol%, but during crystallization, significant migration of the melt component occurred, perhaps by crystal settling and/or filter pressing. Stone 2 acquired an enhanced proportion of residual melt and, thus, higher proportions of late-stage materials such as PBM, oxides, and phosphates.Within the PBM, clinopyroxene poikiloblastically encloses fayalite and silica. At least some of the PBM had already formed by decomposition of pyroxferroite before the major shock that caused the very scarce brecciation within Los Angeles. However, the low abundance of fractures within PBM, in comparison to pyroxene and some other minerals, may be an indication that the textures of PBM regions typically did not assume their final detailed configuration until after the last major shock. The steep slope of a pyroxene mg-Cr correlation suggests that igneous crystallization occurred at higher fO 2 in Los Angeles than in otherwise similar shergottites such as QUE 94201, Shergotty, and Zagami.

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“…The higher abundance of REEs in kirschsteinite relative to olivine in both AdoR and LEW 86010 can be attributed to the higher Ca content of kirschsteinite compared to olivine. The distribution of trace elements within a phase is directly affected by the composition of that phase (e.g., McKay 1986 andMcKay et al 1986). McKay et al (1986) showed that REE partition coefficients in synthetic pyroxenes correlate strongly with the wollastonite content of the pyroxene.…”

Section: Comparison Of Ador With Lew 86010mentioning

confidence: 99%

“…The distribution of trace elements within a phase is directly affected by the composition of that phase (e.g., McKay 1986 andMcKay et al 1986). McKay et al (1986) showed that REE partition coefficients in synthetic pyroxenes correlate strongly with the wollastonite content of the pyroxene. This can be understood in terms of substitution into the M2 site in pyroxenes (and olivines).…”

Section: Comparison Of Ador With Lew 86010mentioning

confidence: 99%

Thermal histories of angrite meteorites: Trace element partitioning among silicate minerals in Angra dos Reis, Lewis Cliff 86010, and experimental analogs

Fittipaldo

Jones

Shearer

2005

Meteoritics &Amp; Planetary Science

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Abstract-We measured rare earth element (REE) abundances in selected silicate phases in the angrites Angra dos Reis (AdoR) and Lewis Cliff (LEW) 86010 in order to further clarify the thermal history of AdoR. We also carried out a preliminary experimental study designed to examine apparent REE partitioning between silicates (fassaite, olivine, kirschsteinite, and melt) in synthetic analogs of angrites under disequilibrium conditions at liquidus temperatures. Silicates in AdoR are homogeneous with respect to major, minor, and trace elements, which is consistent with the interpretation that AdoR underwent extensive subsolidus equilibration. REE distributions in olivine and kirschsteinite in AdoR are similar to those in LEW 86010 and are consistent with the formation of kirschsteinite by exsolution from olivine during cooling and/or annealing. There is no evidence for a disequilibrium trace element signature that could have been inherited from rapid cooling at liquidus temperatures. This is supported by our petrographic observations of the occurrence of kirschsteinite within olivine aggregates in AdoR. Olivine/kirschsteinite pairs in AdoR record closure temperatures around 600-650 °C.

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Clinopyroxene REE distribution coefficients for shergottites: The REE content of the Shergotty melt

Cited by 166 publications

References 21 publications

Rare Earth Elements as an Indicator to Origins of Skarn Deposits: Examples of the Kamioka Zn‐Pb and Yoshiwara‐Sannotake Cu(–Fe) Deposits in Japan

Rare Earth Elements as an Indicator to Origins of Skarn Deposits: Examples of the Kamioka Zn‐Pb and Yoshiwara‐Sannotake Cu(–Fe) Deposits in Japan

Los Angeles: A tale of two stones

Thermal histories of angrite meteorites: Trace element partitioning among silicate minerals in Angra dos Reis, Lewis Cliff 86010, and experimental analogs

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