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WE ACKNOWLEDGE THE FINANCIAL SUPPORT PROVIDED BY THE FOLLOWING INSTITUTIONS

unescoUnesco
United Nations Educational, Scientific and Cultural Organization, a laboratory of ideas to forge universal agreements on emerging ethical issues

igcpIGCP
International Geoscience Programme, a cooperative enterprise of UNESCO and IUGS that provides a multi-discipline platform to exchange knowledge on geological studies of global importance

iugsIUGS
International Union of Geological Sciences, the non-governmental scientific organization that promotes the study of geological problems of global significance


Highlights

IMA2010, Budapest
We announce that our colleague Edina Szappanosné-Vágó has been the recipient of an EMU poster prize at the IMA 2010. Congratulations!!!

Geological Survey of India
A working group on IGCP-540 Project has been established at the Geological Survey of India. Details on the GSI web site

Gold and flincs

esempi di inclusioni fluide nei minerali

Composition of hydrothermal fluids of orogenic gold deposits from state-of-the-art fluid inclusion microanalysis, and applications to mineral exploration


This UNESCO-IGCP project No. 540 considers orogenic Au deposits, i.e. an important mineral resource of our planet. Orogenic deposits are vein networks made of quartz-carbonates-sulfides assemblages that generated during a large part of the Earth's history, starting from the Archean aeon. These networks formed by syn-tectonic flow of Au-rich hydrothermal fluids through large sections of orogenic belts. Because this flow controlled how Au was transported and deposited over time, the determination of the physical and chemical properties of the hydrothermal fluid provides fundamental information on the processes that form mineralised vein networks.

The object of our work is using fluid inclusions as micro-samples of the Au-bearing fluid. Fluid inclusions are minuscule droplets of aqueous fluids encapsulated within minerals, and those found within orogenic deposits contain aliquots of the Au-rich fluid. These inclusions have long been used for modelling the genesis of orogenic deposits. In this project, we want to apply a multi-technique analytical approach to implement the knowledge on Au-bearing fluid inclusions, and aim to apply this approach to the largest number of case studies

We consider the following analytical strategy in fluid inclusion studies:

  1. Petrographic identification of co-genetic inclusions related to Au deposition;
  2. Quantitative measurements of the liquid/vapour ratio in the fluid inclusions (e.g., by spindle-stage);
  3. Microthermometric determination of phase transitions;
  4. Laser Ablation-ICP-Mass Spectrometry of single representative fluid inclusions to determine the concentration of Au and other major and trace chemical components in the ore fluid;
  5. Raman spectroscopy to determine nature and composition of the vapour phase;
  6. SEM and X-ray diffraction analysis of all the minerals that make the assemblages of the Au-bearing veins.

This data set has never been compiled systematically at a global scale, and data from LA-ICP-MS is scarce. Thus, this study proposes a comprehensive and quantitative approach to the study of fluid inclusions in orogenic gold deposits. These data will provide fundamental ingredients of working genetic models.