REE in skarn systems: A LA-ICP-MS study of garnets from the Crown Jewel gold deposit

Gaspar, Miguel; Knaack, Charles; Meinert, Lawrence D.; Moretti, Roberto

doi:10.1016/j.gca.2007.09.033

Cited by 239 publications

(146 citation statements)

References 72 publications

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“…Uranium in both Grt1 and Grt2 has an obviously positive correlation with LREE (Figure 8b (Figure 8f), implying a similar substitution mechanism for LREEs in the Xinqiao garnet. Additionally, previous studies have documented that garnet has the distinct ability to fractionate REEs [11], which is evidenced in the Xinqiao garnet [18]. The positive correlation between U and LREEs (Figure 8b-f) further indicates that U is hosted within the garnet structure.…”

Section: Occurrence Of Uranium In the Garnetmentioning

confidence: 55%

“…Importantly, the contact boundary between Grt1 and Grt2 is irregular (Figure 4h), indicating replacement texture, rather than growth zoning. These two garnets, therefore, correspond to two different generations, i.e., the early generation (Grt1) and the late generation (Grt2), rather than the growth zoning of garnet normally documented in other studies [11,53].…”

Section: Sample Descriptionsmentioning

confidence: 77%

“…On the other hand, the poor correlation between U and HREE also indicates that the primary U incorporation mechanism for the Xinqiao garnet is not surface sorption during rapid crystal growth of the garnet related to fluid infiltration, because surface sorption commonly causes U to correlate positively with both light rare earth element (LREE) and HREE in garnet [16,21]. For grandite or andradite, the incorporation of U is primarily achieved by coupled substitution of Ca 2+ in the dodecahedral position on the basis of similar ionic radii and charge balance ( [11,16,60,61], which can be interpreted to be the U incorporation mechanism for the Xinqiao garnet. Uranium in both Grt1 and Grt2 has an obviously positive correlation with LREE (Figure 8b (Figure 8f), implying a similar substitution mechanism for LREEs in the Xinqiao garnet.…”

Section: Occurrence Of Uranium In the Garnetmentioning

confidence: 99%

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Dating Ore Deposit Using Garnet U–Pb Geochronology: Example from the Xinqiao Cu–S–Fe–Au Deposit, Eastern China

et al. 2018

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Abstract:The large Xinqiao Cu-S-Fe-Au deposit in the Tongling ore district, Eastern China, is characterized by a large-scale stratiform orebody, in which garnet is widely distributed as the main gangue mineral associated with mineralization. Xinqiao garnet can be divided into early (Grt1) and late (Grt2) generations based on extensive back-scattered electron (BSE) imaging observations. Laser ablation (LA)-ICP-MS trace element and U-Pb isotope composition analyses indicate that uranium occurs homogeneously within the Xinqiao garnet, and Grt1 and Grt2 have weighted average 207 Pb-corrected 206 Pb/ 238 U ages of 137.0 ± 7.8 Ma (Mean standard weighted deviation (MSWD) = 4.9) and 129.6 ± 7.1 Ma (MSWD = 1.6), respectively, similar to the zircon U-Pb age (139.6 ± 1.5 Ma) of the Jitou intrusion. These garnet U-Pb ages, combined with the low MnO content and various Y/Ho ratios, suggest that the Xinqiao garnet is likely to have a magmatic hydrothermal replacement origin associated with the Jitou stock. Based on previous studies of the Xinqiao deposit, we infer that the Xinqiao stratiform orebody may have formed from the Early Cretaceous magmatic hydrothermal fluids associated with the Jitou stock, and may have been generated by the Early Cretaceous tectono-thermal event in Eastern China.

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Section: Occurrence Of Uranium In the Garnetmentioning

confidence: 55%

Section: Sample Descriptionsmentioning

confidence: 77%

Section: Occurrence Of Uranium In the Garnetmentioning

confidence: 99%

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Dating Ore Deposit Using Garnet U–Pb Geochronology: Example from the Xinqiao Cu–S–Fe–Au Deposit, Eastern China

et al. 2018

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“…Because of the anomalous enrichment of these garnets with LREE, their patterns have a negative slope: (La/Yb) = 11-16. Garnets from skarns of Crown Jewel gold deposit (Washington State, USA) [16] were studied in more detail. They are represented by varieties of grossular-andradite series with fairly wide variations in the contents of grossular and andradite.…”

Section: Gabbrosmentioning

confidence: 99%

“…It is likely that similar ionic radii of Zr 4+ and HREE are an important determinant of particularly high values of D (zircon / melt) for them, and that these REE are characterized by a high degree of compatibility with the crystal structure of zircons. In the study of synthetic zircon by using cathodoluminescence method it has been found that their patterns contain a series of narrow lines in the area of 200-500 nm that were attributed to the REE such as Sm, Eu, Tb, Dy and Er [16]. In addition, on a laser-fluorescent patterns of zircons from garnet amphibolites of the Cape Kamchatka (Kamchatka, Russia) there were also determined the lines, which were attributed to Er 3+ ions [101].…”

Section: Zirconsmentioning

confidence: 99%

Consistent patterns of rare earth element distribution in accessory minerals from rocks of mafic-ultramafic complexes

Lesnov

2013

Open Geosciences

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This paper summarizes analytical data accumulated in the world literature and other materials about the regularities of the REE distribution in minerals contained in ultramafic and mafic rocks as accessory phases. These minerals are tentatively divided into two groups. The first includes garnets, zircons, apatites and perovskites, which can accumulate increased amounts of REE in their structure. The second consists of minerals whose structure can accumulate only limited contents of these trace elements. These are chrome-spinels, ilmenites, and micas. These minerals, in respect of REE geochemistry, are studied to a varying degree because of the different levels of accumulations of these elements, different degrees of occurrence in rocks, tiny sizes of their grains and other reasons. The analytical database formed on their basis includes about 600 original analyses. The overwhelming majority of presently available data on REE geochemistry in accessory minerals from ultramafic and mafic rocks have been published only in the recent 15 years. The studies became possible due to the development and introduction of new highly sensible microprobe analyses allowing detection of REE and many other trace elements in minerals grains directly in thin sections. The greatest numbers of these analyses were performed for garnets and zircons, fewer for apatites, and the fewest for chrome-spinels, ilmenites, micas, and perovskites. In general, the regularities of REE distribution in these minerals from ultramafic and mafic rocks are less studied compared to the rock-forming minerals from ultramafic and mafic rocks. Among the analytical methods, which were used to study the REE composition of accessory minerals, the most efficient was the mass-spectrometry with inductively coupled plasma (ICP-MS).Keywords: REE distribution • ultramafic and mafic rocks • accessory minerals © Versita Sp. z o.o.

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Garnet composition as an indicator of skarn formation: LA‐ICP‐MS and EPMA studies on oscillatory zoned garnets from the Haobugao skarn deposit, Inner Mongolia, China

et al. 2018

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Oscillatory zoned garnets are widespread in the Haobugao skarn‐type copper–lead–zinc–iron polymetallic deposit, and they can record garnet growing process in the early stages of metallogenesis. In order to investigate the skarn‐forming process and hydrothermal fluid evolution of the Haobugao deposit, major, trace, and rare earth element (REE) contents of oscillatory zoned garnets were analysed by electron probe microscope analysis (EPMA) and laser‐ablation inductively‐coupled plasma mass spectrometry (LA‐ICP‐MS) techniques. Three distinct generations of garnets were identified: the first generation garnets (Grt I) are Fe‐rich, euhedral, fine‐ to coarse‐grained, isotropic, show characteristic concentric oscillatory zoning, and have light rare earth element (LREE)‐enriched and heavy rare earth element (HREE)‐depleted REE patterns, with strong positive Eu anomalies and low ΣREE concentrations. The second generation garnets (Grt II) are Al‐rich, anhedral to subhedral, anisotropic, with abundant oscillatory zoning alone the growth lines, and have LREE‐depleted and HREE‐enriched REE patterns, with negligible Eu anomalies and relatively higher ΣREE concentrations. The third generation garnets (Grt III) are anhedral, anisotropic and generally occurred at the rim of pre‐existing Grt I or beside fractures that cut through the pre‐existing Grt I crystals. All these three generations garnets show oscillatory zoning under an optical microscope and have different compositions from each other, but there's limited chemical zoning (such as bell‐shaped zoning of major elements) in each individual garnet crystal. The texture and composition characteristics of the garnets indicate that the Grt I is precipitated rapidly from high temperature and oxidized magmatic fluids by advective metasomatism, in a high water/rock ratio condition; the Grt II is precipitated from low temperature residual fluids that were in equilibrium with the host rock by diffusive metasomatism, in a low water/rock ratio condition; and the Grt III is formed by retrograde hydrothermal‐metasomatic alteration of pre‐existing garnets. The incorporation of REE into garnet is controlled by its crystal chemistry and fluid composition, dominated by the YAG (yttrium aluminium garnet) ‐type substitution mechanism ()X2+−1VIIIREE3++1VIIISi4+−1IVZ3++1IV.

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REE in skarn systems: A LA-ICP-MS study of garnets from the Crown Jewel gold deposit

Cited by 239 publications

References 72 publications

Dating Ore Deposit Using Garnet U–Pb Geochronology: Example from the Xinqiao Cu–S–Fe–Au Deposit, Eastern China

Dating Ore Deposit Using Garnet U–Pb Geochronology: Example from the Xinqiao Cu–S–Fe–Au Deposit, Eastern China

Consistent patterns of rare earth element distribution in accessory minerals from rocks of mafic-ultramafic complexes

Garnet composition as an indicator of skarn formation: LA‐ICP‐MS and EPMA studies on oscillatory zoned garnets from the Haobugao skarn deposit, Inner Mongolia, China

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