Crystallisation conditions (T, P, fO2) from mineral chemistry of Cu- and Au-mineralised alkaline intrusions in the Red River–Jinshajiang alkaline igneous belt, western Yunnan Province, China

Bi, Xian‐Wu; Hu, Ruizhong; Hanley, Jacob J.; Mungall, James E.; Peng, Jiantang; Shang, Liang; Kai-xing, WU; Yan, Suang; Liu, Hongli; Hu, Xiaoyan

doi:10.1007/s00710-009-0047-4

Cited by 53 publications

(9 citation statements)

References 52 publications

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“…5.16b shows the K/Rb ratio. This has been shown by Blevin (2004) and Xianwu et al (2009) to discriminate highly fractionated melts as Rb is progressively enriched in residual melts relative to K. From this ratio the Crenulated Grennaite can be observed to be the most fractionated of the Grennaites. The Pulaskite is the least fractionated of all the magmas.…”

Section: Alkalinity Al-saturation and Fractionation Plotsmentioning

confidence: 83%

The influence of magmatic and volatile evolution upon lanthanoid fractionation within peralkaline magmas (Norra Kärr, Sweden)

Dobrzański¹,

Walcott

Kirstein³

et al. 2019

Applied Earth Science

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The lanthanoid elements, and in particular the heavier lanthanoids, are essential in the manufacture of advanced technologies due to their unique magnetic, spectral and luminescence properties. However, despite advances in the understanding the behaviour of lanthanoids within chemistry, physics and materials science, the behaviour of these elements within geological systems and in particular the processes by which they become concentrated to form economic ore deposits is still poorly understood.The southern Swedish Norra Kärr lanthanoid-deposit represents a significant European lanthanoid resource of 0.19 Mt T-LnO, with the principal ore domains exhibiting ore-grades between 0.48 -0.69 % T-LnO. Despite its economic significance, the formation of the Norra Kärr intrusion and its economic ore bodies is still not fully understood. However, the intrusion represents an ideal locality to study the concentration of lanthanoids within a peralkaline magma due to the presence of an economically important ore resource; a particular bias towards the economically important heavy- [Ln]; and zonation between light and heavy-[Ln] within separate ore domains.Previous work on the intrusion has primarily focused on analysing the main ore-domains at the expense of other lithologies with the data collected used to develop models for the whole intrusion. This study has analysed the petrology, minerology and whole rock geochemical characteristics of all the lithologies of Norra Kärr and placed the intrusion into the wider structural context of deformation within the Baltic shield at the time of emplacement. These new data and interpretations have been used to test the existing models and develop a new model for the emplacement of Norra Kärr; to better contextualise the formation of the ore domains; and to offer a new model for the light-[Ln] vs heavy-[Ln] zonation observed within the ore-body as a whole.This study has demonstrated that Norra Kärr was emplaced in two magmatic phases, possibly as a series of dyke intrusions; with the first phase magmas more enriched in [Ln] than the second phase magmas. The ore domains developed as a series of cryptic units due to fractionation of the Grennaite-portion of the first magmatic phase. The [Ln]-concentrations were shown to initially increase from the Contact Grennaite to the Pegmatite-Host Grennaite, before enriching in the light- [Ln] and depleting in the heavy- [Ln] as observed in the Crenulated Grennaite. The second phase magmas (Pulaskite-type) display a different minerology to the first phase partially due to due to higher aHF and a more reduced magmatic chemistry. These second phase magmas may have been emplaced due to the effects of ongoing shearing of the intrusion, with the Lakarpite developing its complex chemistry and petrology due to interaction with the still warm Pegmatite-Host Grennaite.This study has demonstrated that a progressive increase in [Ln] within a melt is possible due to aegirine crystallisation, and that the observed variation in light-[Ln] vs heavy-[Ln] within th...

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Section: Alkalinity Al-saturation and Fractionation Plotsmentioning

confidence: 83%

The influence of magmatic and volatile evolution upon lanthanoid fractionation within peralkaline magmas (Norra Kärr, Sweden)

Dobrzański¹,

Walcott

Kirstein³

et al. 2019

Applied Earth Science

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“…Then, influx of meteoric water caused the dissolution of early-formed copper sulfides, resulting in remobilization of Cu-Mo into the silicic veins. [45][46][47] Casino (Selby and Nesbitt, 2000) [11] , Miduk (Boomeri et al, 2009), Sarcheshmeh (Boomeri et al, 2010) [48] , Los Pelambres (Taylor, 1983) [41] and Santa Rita (Jacobs and Parry, 1979) [49] . Similar symbols as in Figure 4.…”

Section: Resultsmentioning

confidence: 99%

“…[9] In this study, in addition to describing geological and mineralogical features of the Lar Cu-Mo prospect, we present new biotite electron probe micro-analyzer data due to the composition of biotite reflects the chemical characteristics of the rocks, associated hydrothermal fluids, and the physicochemical conditions of their formation. [10][11][12][13] With data obtained, the chemical composition of biotite and its halogen chemistry, temperature, and oxygen fugacity values were ORIGINAL ARTICLE calculated in the shoshonitic igneous rocks and alteration zones. All these helped constrain the physicochemical conditions of the Lar Cu-Mo prospect.…”

Section: Introductionmentioning

confidence: 99%

Untitled

Moradi¹

2017

IJGP

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Background and Objective: The Lar Cu-Mo prospect is located in Sistan suture zone, southeast of Iran. In this study, the chemical composition of biotite is determined using electron probe micro-analyzer in shoshonitic igneous rocks. Shoshonitic rocks are syenitic to monzonitic in composition that can be divided into the granular and porphyroid groups. Methods: Studying biotites generally occurs as primary and secondary types. The primary biotites are large poikilitic phenocrysts associated with Fe-Ti oxides, giving the rocks a spotted texture. In addition, secondary biotites show varying size, color, and shape. All of the Lar analyzed biotites are Mg-and Ti-rich and F-and Cl-poor. Analyses of the Lar biotites suggested that crystallization took place at an average temperature of 731°C and 640°C for primary and secondary samples, respectively. Results: Estimation of the oxygen fugacity, based on chemical composition and Fe3+ content of biotite, shows that the oxygen fugacity was limited in fayalitemagnetite quartz to middle of HM buffers in quality and was about 10 −12 to 10 −14 bar in quantity for primary and secondary type, respectively. Halogen fugacity ratios in biotite show that the Lar porphyroid rocks (ore-bearing) are affected mainly by meteoric water than granular type (barren). Calculated halogen fugacity values for biotite in the Lar Cu-Mo prospect are consistent with many other porphyry copper-forming systems. Conclusion: The Lar Cu-Mo prospect was formed by the hydrothermal activity related to the syenitic to monzonitic porphyroid igneous rocks with shoshonitic nature which introduces the Lar igneous complex volcanic sequence. The hydrothermal alterations are limited and occurred as silicic, potassic, phyllic, propylitic, and argillic. Hypogene sulfide minerals mainly occur as disseminated and sulfidic and silicic veins and veinlets consisting of chalcopyrite, bornite, molybdenite, and minor pyrite. Biotite as main ferromagnesian mineral of host rocks occurs as primary in less altered rocks and secondary in the alteration areas.

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“…Amphibole and biotite thermobarometry have been used widely to estimate the emplacement pressure ( P ) and temperature ( T ) of calc-alkaline igneous rocks (Anderson and Smith, 1995; Putirka, 2008; Ridolfi et al , 2010). Similarly, the halogen (F, Cl) contents of biotite and hornblende have been used to investigate the characteristics and the evolution of the magmas and associated hydrothermal fluids (Imai, 2000; Selby and Nesbitt, 2000; Boomeri et al , 2009, 2010; Xianwu et al , 2009; Siahcheshm et al , 2012).…”

Section: Introductionmentioning

confidence: 99%

Magma chamber evolution of the Ardestan pluton, Central Iran: evidence from mineral chemistry, zircon composition and crystal size distribution

Babazadeh

Furman

Cottle

et al. 2019

MinMag

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The Oligo–Miocene Ardestan quartz diorite to tonalite is part of widespread Cenozoic magmatism within the Urumieh–Dokhtar Magmatic Assemblage of Iran. The Ardestan pluton is composed mainly of varying proportions of plagioclase feldspar (normally zoned from bytownite to andesine), amphibole (magnesio-hornblende) and biotite. Biotite exhibits a range of Al values (~2–2.8 apfu) over very restricted Fe# ratios (0.42–0.56) which are characteristic of continental arc magmatic suites. High Ti2O contents of biotite (<6.1 wt.%) suggest a magmatic origin. Ti-in-biotite geothermometery gives a mean crystallisation temperature of 730 ± 56°C, slightly higher than calculated TZr.Ti°C (716 ± 50°C) and similar to the average TZr.sat°C (735 ± 26°C). These results are consistent with the low bulk-rock SiO2 contents, which provide minimum estimates of temperature and indicate zircon crystallised from a fractionated magma. Zircons from the Ardestan pluton have high (Sm/La)N (>10) ratios suggesting a magmatic origin. T–$f_{{\rm O}_{\rm 2}}$ calculations of oxygen fugacity between –13.6 to –16.9 indicate oxidising crystallisation conditions between the Ni–NiO (NNO) and Fe2O3–Fe3O4 (HM) buffers. Tight linear trends of log (XF/XOH), log (XCl/XOH) and log (XCl/XOH) vs. XMg represent a narrow range of $f_{{\rm H}_2O}$, fHF and fHCl, clearly indicating that physico-chemical conditions were essentially constant throughout the formation of magmatic biotite. The shape of crystal size distribution curves along with the medium Al and Mg contents in amphibole and biotite, respectively, are consistent with a history of magma mixing involving injections of basic magma into the evolving felsic chamber. Calculated residence time for Ardestan plagioclase crystals of ~630 years support field evidence that these plutons were emplaced at shallow depths.

show abstract

Crystallisation conditions (T, P, fO2) from mineral chemistry of Cu- and Au-mineralised alkaline intrusions in the Red River–Jinshajiang alkaline igneous belt, western Yunnan Province, China

Cited by 53 publications

References 52 publications

The influence of magmatic and volatile evolution upon lanthanoid fractionation within peralkaline magmas (Norra Kärr, Sweden)

The influence of magmatic and volatile evolution upon lanthanoid fractionation within peralkaline magmas (Norra Kärr, Sweden)

Untitled

Magma chamber evolution of the Ardestan pluton, Central Iran: evidence from mineral chemistry, zircon composition and crystal size distribution

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