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Chemistry and P-T of fluids trapped in co-genetic opaque ore and transparent gangue minerals: What are the real ore-precipitating fluids?

English title Chemistry and P-T of fluids trapped in co-genetic opaque ore and transparent gangue minerals: What are the real ore-precipitating fluids?
Applicant Kouzmanov Kalin
Number 147076
Funding scheme Project funding (Div. I-III)
Research institution Département des sciences de la Terre Université de Genève
Institution of higher education University of Geneva - GE
Main discipline Geochemistry
Start/End 01.04.2013 - 31.12.2013
Approved amount 55'800.00
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Keywords (6)

LA-ICP-MS; IR microscopy and microthermometry; porphyry-related deposits; ore-forming fluids; co-genetic ore and gangue minerals; fluid inclusions

Lay Summary (French)

Lead
Une des limites de l'approche standard dans la recherche sur les inclusions fluides en métallogénie réside dans la difficulté de vérifier l'hypothèse que les minéraux de gangue, utilisés pour ces analyses, et les minéraux économiques associés sont cogénétiques. Ce projet vise à répondre à cette question fondamentale en comparant la composition et les paramètres P-T d’assemblages d'inclusions fluides piégés dans les deux types de minéraux au sein de gisements de la famille porphyre-épithermale.
Lay summary

Combiner l’utilisation de la microscopie et la microthermométrie en lumière infrarouge proche (IRP) avec des analyses ICP-MS par ablation laser (LA-ICP-MS) sur des inclusions fluides piégées dans des minéraux économiques permet d’avancer considérablement dans l'analyse des fluides crustaux responsables de la précipitation des métaux dans les gisements hydrothermaux. La combinaison de ces techniques permet d'analyser avec succès des inclusions fluides individuelles qui restent opaques en lumière visible mais sont transparentes en lumière IRP. Utiliser cette nouvelle approche analytique en parallèle avec la microthermométrie sur des minéraux transparents de gangue offre de nouvelles opportunités de comparer la composition chimique et les conditions P-T de piégeage des fluides dans ces minéraux métalliques et de gangue cogénétiques.

Ce projet vise à: i) effectuer des tests sur ??plusieurs paires de minéraux de gangue / minerai (quartz-pyrite, quartz-wolframite, quartz-stibine) provenant  d'environnements hydrothermaux différents afin de mieux évaluer l'application potentielle de la méthode, ii) appliquer la nouvelle approche analytique  et entreprendre une étude détaillée sur inclusions fluides des veines polymétalliques du district minier de Butte dans le Montana (USA), iii) étudier la composition chimique des inclusions fluides piégées dans l’énargite du gisement  épithermal acide de Lépanto aux Philippines.

Direct link to Lay Summary Last update: 28.03.2013

Responsible applicant and co-applicants

Employees

Name Institute

Publications

Publication
Fluid Inclusion Studies in Opaque Ore Minerals: I. Trace Element Content and Physical Properties of Ore Minerals Controlling Textural Features in Transmitted Near-Infrared Light Microscopy
Ortelli M., Kouzmanov K., Wälle M., Ubrig N., Casanova V. (2018), Fluid Inclusion Studies in Opaque Ore Minerals: I. Trace Element Content and Physical Properties of Ore Minerals Controlling Textural Features in Transmitted Near-Infrared Light Microscopy, in Economic Geology, 113(8), 1845-1860.
Fluid Inclusion Studies in Opaque Ore Minerals: II. A Comparative Study of Syngenetic Synthetic Fluid Inclusions Hosted in Quartz and Opaque Minerals
Casanova V., Kouzmanov K., Audétat A., Wälle M., Ubrig N., Ortelli M., Fontboté L. (2018), Fluid Inclusion Studies in Opaque Ore Minerals: II. A Comparative Study of Syngenetic Synthetic Fluid Inclusions Hosted in Quartz and Opaque Minerals, in Economic Geology, 113(8), 1861-1883.
Gold speciation and transport in geological fluids: insights from experiments and physical-chemical modelling
Pokrovski Gleb S., Akinief Nikolay N., Borisova Anastassia Y., Zotov Alexandre V., Kouzmanov Kalin (2014), Gold speciation and transport in geological fluids: insights from experiments and physical-chemical modelling, in Gold-Transporting Hydrothermal Fluids in the Earth’s Crust, 402, 9-70.
Tennantite-tetrahedrite series fromthe Madan Pb-Zn deposits, Central Rhodopes, Bulgaria
Vassileva Rossitsa, Atanassova Radostina, Kouzmanov Kalin (2014), Tennantite-tetrahedrite series fromthe Madan Pb-Zn deposits, Central Rhodopes, Bulgaria, in Mineralogy and Petrology, 108, 515-531.

Collaboration

Group / person Country
Types of collaboration
Dr. Rossitsa Vassileva, Geological Institute, BAS Bulgaria (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Dr. Nicolas Ubrig - Condesed Matter Physics Department, University of Geneva Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. Larryn Diamond - University of Bern Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. John Dilles - Oregon State University United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Dr. Brian Rusk - Western Washington University United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Dr. Jeffrey W. Hedenquist - consultant, Ottawa, Canada Canada (North America)
- in-depth/constructive exchanges on approaches, methods or results
Prof. Christoph Heinrich, Dr. Markus Wälle - ETH Zürich Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. Torsten Vennemann - Institute of Mineralogy and Geochemistry, University of Lausanne Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Swiss Geoscience Meeting 2013 Poster Timing of polymetallic Pb-Zn mineralisation in the Laki district, southern Bulgaria – constraints from 40Ar/39Ar dates 15.11.2013 Lausanne, Switzerland Kouzmanov Kalin;
12th SGA Biennial Meeting 2013 Talk given at a conference District-scale evolution in the Main Stage veins at Butte, Montana 12.08.2013 Uppsala, Sweden Kouzmanov Kalin; Ortelli Melissa;
12th SGA Biennial Meeting 2013 Talk given at a conference Metal zoning and precipitation mechanisms in porphyry systems 12.08.2013 Uppsala, Suède, Sweden Ortelli Melissa; Kouzmanov Kalin;


Associated projects

Number Title Start Funding scheme
127123 Chemistry and P-T of fluids trapped in co-genetic opaque ore and transparent gangue minerals: What are the real ore-precipitating fluids? 01.01.2010 Project funding (Div. I-III)
134872 Fluids and ore forming processes in the continental crust (cont) 01.04.2011 Project funding (Div. I-III)
133781 Near-infrared equipment for high-precision microthermometry measurements using the infrared microscopy technique 01.12.2010 R'EQUIP

Abstract

One of the limitations of the standard approach in fluid inclusion research conducted on ore deposits consists of the difficulty to verify the broadly accepted assumption that gangue minerals, mainly used in fluid inclusion studies, and the intergrown ore minerals are cogenetic. In fact, there is growing evidence that ore mineralization in hydrothermal systems may form from episodic events of multiple fluid sources. The primary aim of the project is to address this fundamental question by comparing the chemistry and P-T characteristics of well constrained fluid inclusion assemblages in intergrown ore and gangue minerals from selected porphyry and epithermal deposits.The combination of near-infrared (NIR) microscopy and microthermometry and laser-ablation inductively coupled plasma mass-spectrometry (LA-ICP-MS) techniques allows successful analysis of individual fluid inclusions of real ore-precipitating fluids, hosted by opaque to the visible light but transparent to the NIR radiation ore minerals such as pyrite, enargite, wolframite, hematite, stibnite, and tetrahedrite. Joining this novel analytical approach and the standard microthermometry on transparent gangue minerals offers new opportunities to compare the chemistry and P-T conditions of entrapment of fluids in texturally syngenetic ore and gangue minerals from various hydrothermal ore deposits. This proposal seeks funding for an extension of 9 months for one PhD student who has started working on this project in January 2010. The principal aims of the project have not changed and they are the following: i) to perform test runs on several gangue/ore mineral pairs (e.g., quartz-pyrite, quartz-stibnite, quartz-wolframite) from a variety of hydrothermal environments in order to better evaluate the potential application of the new methodology to study different ore deposit types and to develop, if necessary, the established analytical protocols; ii) to apply the new methodology studying ore-forming fluids in the Butte polymetallic district, Montana, USA. The Butte deposit has been chosen because the district geology is very well studied; relative time relationship between the different mineralizing events is clear; there is a good textural evidence of co-genetic quartz and ore minerals which are suitable for NIR microthermometry; and extensive microthermometry data and LA-ICP-MS results on quartz-hosted fluids are available and can be used as a background for further studies. Detailed sampling at Butte (141 samples in total) along an E-W profile from the core of the system (Leonard mine) towards the western periphery (Orphan Girl mine) was performed in 2010 on surface and in the Anaconda (GRL) collection. Vertical profiles were sampled in three of the mines from the central part of the district - Leonard (580m vertical interval), Kelley (1050m vertical interval) and Steward (320m vertical interval). The samples selected offer the possibility to work on fluids trapped in large temperature range - from temperatures as high as >450°C (porphyry environment), intermediate temperatures (300-200°C, corresponding roughly to the temperatures of the Main Stage polymetallic mineralization at Butte), down to low-temperatures (<150°C). Thus, NIR experiments will cover a temperature range, which is typical for most of the known hydrothermal ore deposits and can be used to assess the applicability of this technique to other ore deposit types. The second part concerns a sub-project, which is running in parallel and is conducted by the principal applicant, aiming to study the chemistry (by LA-ICP-MS) and stable (oxygen and hydrogen) isotopic composition of enargite-hosted fluid inclusions from the Lepanto high-sulfidation epithermal deposit, Philippines. Nowhere the spatial association between epithermal and porphyry Cu-Au deposits is better exposed than in northern Luzon, where the Lepanto deposit overlies the Far Southeast (FSE) porphyry Cu-Au deposit, both being world-class ore bodies. The study is carried out on samples from a profile across the main ore body at Lepanto previously studied by NIR microthermometry, noble gas analysis and sulphur isotope geochemistry, all suggesting progressive mixing with external (meteoric) fluids from the FSE porphyry (centre of the system) away laterally.The acquired new results and interpretations will be combined with previous geological, fluid inclusion and stable isotope data on the studied deposits to develop models for fluid processes which govern ore-precipitation mechanisms at the porphyry-epithermal interface. Such results would have implications also for general understanding of the mechanisms of hydrothermal ore-formation.This project acts as a single, coherent piece of independent research aiming to develop and apply novel analytical approach for studying ore-forming fluids. However, it is coordinated with and complements other projects within the Ore Deposits research group at the Department of Mineralogy, University of Geneva, which address the tectonic, magmatic and fluid processes leading to formation of time- and space-clustered porphyry Cu-Au and polymetallic (-Au-Ag) epithermal deposits at convergent margins. Jointly and in close collaboration with the Isotope Geochemistry research group, these projects intend to establish a widespread and complementary research program at the University of Geneva, using state-of-the-art analytical facilities, aiming to understand geological processes which govern the enrichment of economically important elements in the Earth’s crust, leading to formation of ore deposits.
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