Textural and chemical zonation of pyrite at Pajingo: a potential vector to epithermal gold veins

Baker, Timothy D.; Mustard, R.; Brown, Vernon; Pearson, Norman J.; Stanley, Clifford R.; Radford, Nigel; Butler, Ian B.

doi:10.1144/1467-7873/05-077

Cited by 23 publications

(8 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Given the fact that not all boiling horizons are equally mineralized, ratios between Cu, Ag and Pb could be used for discrimination. These results agree with Baker et al (2006) and Kouhestani et al (2017), who showed the usefulness of Cu/Pb and Pb/Ag ratios in pyrite for vectoring to high-grade Au ore zones in low-to intermediate-sulfidation epithermal Au-Ag deposits.…”

Section: Pyrite As a Vector To Mineralization In Low-to Intermediate-supporting

confidence: 92%

Geochemical and micro-textural fingerprints of boiling in pyrite

Román

Reich

Leisen

et al. 2019

Geochimica et Cosmochimica Acta

193

100

View full text Add to dashboard Cite

The chemical composition, textures and mineral associations of pyrite provide key information that help elucidate the evolution of hydrothermal systems. However, linking the compositional and micro-textural features of pyrite with a specific physico-chemical process, e.g., boiling versus nonboiling, remains elusive and challenging. In this study we examine pyrite geochemical and microtextural features and relate these results to pyrite-forming processes at the active Cerro Pabellón Geothermal System (CPGS) in the Altiplano of the northern Chile. We integrate electron microprobe analysis (EMPA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) data with micro-textural observations of pyrite and associated gangue minerals recovered from a ~500 m long drill core that crosscuts the argillic, sub-propylitic and propylitic alteration zones of the CPGS. Additionally, we carried out a Principal Component Analysis (PCA) in order to inspect and understand the main data structure of the pyrite geochemical dataset. The concentrations of precious metals (Au and Ag), metalloids (As, Sb, Se, Bi and Tl), and base and heavy metals (Cu, Co, Ni and Pb) in pyrite from the CPGS are significant. Among the elements analyzed, As, Cu and Pb are the most abundant with concentrations that vary from a few parts per million (ppm) to wt% levels (up to 4.4 wt% of As, 0.5 wt% of Cu and 0.2 wt% of Pb). Based on contemporaneous gangue mineral associations and textures, the mechanisms of pyrite precipitation in the CPGS were inferred. Pyrite formed during vigorous boiling is characterized by relatively high concentrations of As, Cu, Pb, Ag and Au and lower concentrations of Co and Ni compared to pyrite formed under different conditions. These anhedral to euhedral pyrite grains display zones with a porous texture and abundant mineral micro-to nano-inclusions (mainly galena and chalcopyrite) indicating a formation by rapid crystallization. In contrast, pyrite formed under gentle boiling (more gradual cooling and less abrupt physico-chemical variations than in vigorous boiling) to non-boiling conditions is characterized by a higher concentration of Co and Ni, and relatively low concentrations of As, Cu, Pb, Ag and Au. Texturally, these pyrites form aggregates of euhedral and pristine pyrite crystals with scarce pores and mineral inclusions suggesting formation under steadier physico-chemical conditions. Our results show that pyrite can not only record the chemical evolution of hydrothermal fluids, but can also provide critical information related to physicochemical process such as boiling and phase separation. Since boiling of aqueous fluids is a common phenomenon occurring in a variety of pyrite-forming environments, e.g., active continental and seafloor hydrothermal systems, and porphyry Cu-epithermal Au-Ag deposits, pyrite compositional and textural features are a valuable complement for discriminating and tracking boiling events in modern and fossil hydrothermal systems.

show abstract

Section: Pyrite As a Vector To Mineralization In Low-to Intermediate-supporting

confidence: 92%

Geochemical and micro-textural fingerprints of boiling in pyrite

Román

Reich

Leisen

et al. 2019

Geochimica et Cosmochimica Acta

193

100

View full text Add to dashboard Cite

show abstract

“…The absolute values for trace elements presented in this manuscript should be taken with caution, given the different nature of the standards and the samples. However, previous works have shown that good accuracy and precision can be obtained during the analysis of sulphides by LA-ICP-MS using the NIST610 standard [36]. Their research included repeated LA-ICP-MS analysis of a PS-1 (sulphide standard) and obtained values comparable (<5% error) to those resulting from solution [37].…”

Section: Methodsmentioning

confidence: 99%

Mineralogy and Distribution of Critical Elements in the Sn–W–Pb–Ag–Zn Huanuni Deposit, Bolivia

et al. 2019

View full text Add to dashboard Cite

The polymetallic Huanuni deposit, a world-class tin deposit, is part of the Bolivian tin belt. As a likely case for a “mesothermal” or transitional deposit between epithermal and porphyry Sn types (or shallow porphyry Sn), it represents a case that contributes significantly to the systematic study of the distribution of critical elements within the “family” of Bolivian tin deposits. In addition to Sn, Zn and Ag, further economic interest in the area resides in its potential in critical elements such as In, Ga and Ge. This paper provides the first systematic characterisation of the complex mineralogy and mineral chemistry of the Huanuni deposit with the twofold aim of identifying the mineral carriers of critical elements and endeavouring plausible metallogenic processes for the formation of this deposit, by means of a multi-methodological approach. With In concentrations consistently over 2000 ppm, the highest potential for relevant concentrations in this metal resides in widespread tin minerals (cassiterite and stannite) and sphalerite. Hypogene alteration assemblages are hardly developed due to the metasedimentary nature of host rocks, but the occurrence of potassium feldspar, schorl, pyrophyllite and dickite as vein material stand for potassic to phyllic or advanced argillic alteration assemblages and relatively high-temperature (and low pH) mineralising fluids. District-scale mineralogical zonation suggests a thermal zonation with decreasing temperatures from the central to the peripheral areas. A district-scale zonation has been also determined for δ34SVCDT values, which range −7.2‰ to 0.2‰ (mostly −7‰ to −5‰) in the central area and −4.2‰ to 1.0‰ (mainly constrained between −2‰ and 1‰) in peripheral areas. Such values stand for magmatic and metasedimentary sources for sulfur, and their spatial zoning may be related to differential reactivity between mineralising fluids and host rocks, outwardly decreasing from the central to the peripheral areas.

show abstract

“…Chemical variations between pyrites in different alterations zones were investigated as potential indicators of the occurrence of gold veins in an ore deposit. 251 Ohlander et al 252 looked at the possibility of using LA-SF-ICP-MS to quantify the enrichment of trace elements on pyrite surfaces in mine tailings. Although there were many uncertainties in the resulting calculations, they concluded that metals, particularly As and Cu, released by oxidation and weathering of the sulfide minerals, were absorbed onto pyrite surfaces at deeper, unoxidised levels within the tailings.…”

Section: Reference Materialsmentioning

confidence: 99%

Atomic spectrometry update. Environmental analysis

Butler¹,

Cook²,

Harrington³

et al. 2008

J. Anal. At. Spectrom.

View full text Add to dashboard Cite

This is the twenty-forth annual review published in JAAS of the application of atomic spectrometry to the chemical analysis of environmental samples. This Update refers to papers published approximately between September 2007 and August 2008. In the analysis of air, work is focused on the need to collect and characterise ultrafines, i.e. particles below 100 nm in size, and such research is being facilitated through the development of air sampler technologies for subsequent off-line analysis of particles and aerosol mass spectrometric techniques for real-time measurements. In the analysis of water elemental speciation and development of vapour generation techniques for metalloid species continue to attach attention. Data quality and metrological issues are receiving renewed interest in part due to an increase in water quality regulations. In the field of soil and plant analysis, elemental fraction and speciation protocols based upon sequential extraction procedures, chromatographic separation procedures and synchrotron radiation x-ray techniques continue to be utilized and developed. As noted in previous Updates, laser ablation continues to go from strength to strength in being adopted as a solid sampling tool in geochemical analysis. Work continues to be focused on the production, characterization and certification of new geological reference materials. Feedback on this review

show abstract

Textural and chemical zonation of pyrite at Pajingo: a potential vector to epithermal gold veins

Cited by 23 publications

References 9 publications

Geochemical and micro-textural fingerprints of boiling in pyrite

Geochemical and micro-textural fingerprints of boiling in pyrite

Mineralogy and Distribution of Critical Elements in the Sn–W–Pb–Ag–Zn Huanuni Deposit, Bolivia

Atomic spectrometry update. Environmental analysis

Contact Info

Product

Resources

About