Garnets in porphyry–skarn systems: A LA–ICP–MS, fluid inclusion, and stable isotope study of garnets from the Hongniu–Hongshan copper deposit, Zhongdian area, NW Yunnan Province, China

Peng, Huijuan; Zhang, Changqing; Mao, Jingwen; Santosh, M.; Zhang, Yang; Hou, Lin

doi:10.1016/j.jseaes.2014.10.020

Cited by 57 publications

(30 citation statements)

References 53 publications

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“…Most of the oscillatory zoned garnets in the Haobugao skarn deposit are homogeneous and contain no corresponding bell‐shaped chemical zoning as described in previous studies (Ismail et al, ; Peng et al, ; Zuo et al, ). The Grt IA, for example, are characterized by abundance of oscillatory zoning under optical microscope but are generally chemically homogeneous and have no compositional zoning.…”

Section: Results and Interpretationsupporting

confidence: 57%

“…Furthermore, the Grt III are generally distributed beside a crack that cross‐cut the garnet crystal (Figure c,f), or adjacent to fractured oscillatory zoning that corresponding to crystal planes (dark zones in Figure e–f,h), and these alteration‐induced Al‐rich, anisotropic Grt III often have a sharp contact interface with the Fe‐rich, isotropic Grt I (Figure c–f), which proves that grain boundaries and oscillatory zoning, especially fractured zoning, can affect and obstruct hydrothermal diffusion pathways and length scale during retrograde metamorphism (Kim, ; Meth & Carlson, ; Whitney & Seaton, ). This makes the alteration‐induced Grt III look like original chemical zoning and frequently be mistakenly regarded as epitaxial overgrowing garnet, for example, Peng et al () described the alteration‐induced Al‐rich garnet as the third generation garnet which was directly precipitated from the hydrothermal fluids and overgrowing the pre‐existing garnet.…”

Section: Discussionmentioning

confidence: 99%

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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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Section: Results and Interpretationsupporting

confidence: 57%

Section: Discussionmentioning

confidence: 99%

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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“…This includes: (i) poly-atomic interferences such as the generation of argides if using Ar as the plasma gas (e.g., argides of Cu and Ni (e.g., [45])) that may interfere with Pd, Rh, and Ru ( 101 Ru with 61 Ni 40 Ar, and so on); (ii) isobaric interferences between elements which have the same isotopic masses (e.g., 108 Pd with 108 Cd, 115 In with 115 Sn); and (iii) multiple ionization interferences (generally less significant for trace element analysis). An understanding of potential interferences and isotopic proportions is necessary to know whether or not corrections need to be applied (for instance, correction of 101 Ru for 61 Ni 40 Ar when analyzing pentlandite, or 115 In for 115 Sn in stannite, Ni and Sn being major components of the two sulphides). Other potential interferences may not necessitate correction.…”

Section: Nist-610 -612 Synthetic Glass Silicatesmentioning

confidence: 99%

“…These studies have also highlighted that the skarn minerals, rather than sulphides, can be significant sinks for minor metals of potential economic interest. Examples include the extraordinary enrichment of Ga in clinozosite [53], and of Mo, W and Sn is some skarn garnets [95,115], or magnetite [116].…”

Section: Skarn Formationmentioning

confidence: 99%

Trace Element Analysis of Minerals in Magmatic-Hydrothermal Ores by Laser Ablation Inductively-Coupled Plasma Mass Spectrometry: Approaches and Opportunities

et al. 2016

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Laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) has rapidly established itself as the method of choice for generation of multi-element datasets for specific minerals, with broad applications in Earth science. Variation in absolute concentrations of different trace elements within common, widely distributed phases, such as pyrite, iron-oxides (magnetite and hematite), and key accessory minerals, such as apatite and titanite, can be particularly valuable for understanding processes of ore formation, and when trace element distributions vary systematically within a mineral system, for a vector approach in mineral exploration. LA-ICP-MS trace element data can assist in element deportment and geometallurgical studies, providing proof of which minerals host key elements of economic relevance, or elements that are deleterious to various metallurgical processes. This contribution reviews recent advances in LA-ICP-MS methodology, reference standards, the application of the method to new mineral matrices, outstanding analytical uncertainties that impact on the quality and usefulness of trace element data, and future applications of the technique. We illustrate how data interpretation is highly dependent on an adequate understanding of prevailing mineral textures, geological history, and in some cases, crystal structure.

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“…The presence of andradite‐rich garnet with oscillatory zonation in mineralized metasomatic skarn (Figs d, ) may provide additional evidence of brine‐derived mineralization. Garnet of this type has also been reported in several localities of metasomatic skarn related to porphyry or other intrusions and seems to always be associated with brine phases separated from parental magmatic fluids in a boiling state (Smith et al, ; Peng et al, ).…”

Section: Discussionmentioning

confidence: 93%

Mineralogy, Fluid Inclusions, and Sulfur Isotopes of the Huanzala Deposits, Peru: Early Skarn and Late Polymetallic Replacement Style Mineralizations

Suzuki

Hayashi

2019

Resource Geology

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Carbonate‐replacement polymetallic mineralization at the Huanzala deposits (9°51′S, 77°00′W) was conducted in two contrasting stages that occurred in almost the same location. Early‐stage mineralization has a relation with a granodiorite porphyry stock, whereas the late‐stage mineralization is genetically associated with quartz porphyry sills. The early stage involved low to intermediate sulfidation Cu–Zn–(Pb) mineralization associated with metasomatic skarn, and the late stage involved high to intermediate sulfidation Cu–Zn–Pb–(Mn) mineralization associated with hydrothermal alteration characterized by paragonitic sericitization. The orebodies are hosted by steeply dipping (approximately 60°NE) Lower Cretaceous carbonate rocks in a relatively narrow range of approximately 4 km in horizontal extent and less than 1 km in depth. The pathway of the early‐stage brine‐derived fluids (300–>400°C, >33 wt% NaCl equivalent) along a plot of log fnormalS2 against 1000/T is best explained by the progressive dual decline of the fnormalS2 value and the temperature under rock‐buffering conditions; this decline saw the pathway progress through the stability field of pyrrhotite to reach that of pyrite and promoted a decrease in FeS from 14.5 to 1.6 mol% in the sphalerite. In contrast, an explanation for the pathway of the late‐stage fluids (140–290°C, 3–13 wt% NaCl equivalent) is given by an almost isothermal fnormalS2 decline at approximately 270°C, with fnormalS2 passing through the stability field of pyrite–bornite to reach that of chalcopyrite, promoting an increase in FeS from 0.1 to 1.6 mol% in the sphalerite, suggesting gas‐buffering conditions. The ore formation pressure records in the fluid inclusions illustrate an approximately 2‐km erosion during the roughly 2‐Myr total lifetime of the hydrothermal system.

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Garnets in porphyry–skarn systems: A LA–ICP–MS, fluid inclusion, and stable isotope study of garnets from the Hongniu–Hongshan copper deposit, Zhongdian area, NW Yunnan Province, China

Cited by 57 publications

References 53 publications

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

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

Trace Element Analysis of Minerals in Magmatic-Hydrothermal Ores by Laser Ablation Inductively-Coupled Plasma Mass Spectrometry: Approaches and Opportunities

Mineralogy, Fluid Inclusions, and Sulfur Isotopes of the Huanzala Deposits, Peru: Early Skarn and Late Polymetallic Replacement Style Mineralizations

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