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Quantitative Modeling of Ore-Forming Hydrothermal Systems

English title Quantitative Modeling of Ore-Forming Hydrothermal Systems
Applicant Heinrich Christoph
Number 124906
Funding scheme Project funding (Div. I-III)
Research institution Institut für Geochemie und Petrologie ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Geochemistry
Start/End 01.04.2009 - 31.03.2011
Approved amount 655'470.00
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All Disciplines (3)

Discipline
Geochemistry
Geochronology
Other disciplines of Earth Sciences

Keywords (22)

mineral resources; geochemistry; magmatic hydrothermal systems; laser-ablation; ICP-MS; fluid inclusions; LA-MC-ICPMS; hydrodynamics; finite-element simulation; isotope analysis; geochronology; Romania; Bulgaria; SCOPES; ore deposits; fluid; isotope; ICPMS; finite-element modelling; magmatic-hydrothermal; Serbia; Bingham

Lay Summary (English)

Lead
Lay summary

This project investigates the geological processes that lead to the formation of primary resources of industrial metals such as copper, lead, zinc, molybdenum or gold in the Earth’s interior. Several PhD students funded by this project cooperate to understand why some metals are selectively enriched in certain small areas of the Earth's crust, in 100- to 10'000-fold higher concentration compared to normal rocks, and why this occurred only in some locations and at certain periods in the evolution of our planet. Understanding the formation of mineral resource is the foundation for discovering new deposits, which is essential for Switzerland as well as global technical development. Our research also trains students to acquire the geological understanding they need to work successfully and responsibly with the international resource industry. Collaboration with colleagues from resource-rich but economically less-developed countries contributes to mutual awareness of technical and cultural needs in different societies.

Ore formation involves chemical dissolution of trace metals by water-rich fluids or magmatic melts, followed by concentrated re-deposition of metallic minerals in selected areas of the Earth's crust. Our research starts with geological observations and sampling in the field, commonly in regions with known mineral occurrences. Samples are then analysed in the laboratory by different methods. Micro-analysis of tiny relicts of ore-forming solutions enclosed inside minerals is a technique that was developed by our group at ETH Zurich and is now used worldwide. With isotopic analyses of minerals containing radioactive elements we can determine when an ore vein formed, or how long it took for a magma to crystallise. The different field- and lab-based results are linked by computer simulations of the overall process to predict, for example, the flow directions of ore-mineralising fluids beneath a volcano. The same computer models can also be applied to study volcanic eruptions, or the extraction of geothermal energy from the Earth's interior.

 Technical details about this research and about training in resource geology can be found at www.geopetro.ethz.ch/research/orefluids. Zurich's new Earth Science Information and Exhibition center, focusTerra, contains an attractive display about mineral resources, which explains some results from this research in readily understandable form (www.focusterra.ethz.ch).
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Associated projects

Number Title Start Funding scheme
135302 Quantitative Modeling of Ore-Forming Hydrothermal Systems 01.04.2011 Project funding (Div. I-III)
128089 Metal transport and ore deposition: The geology, geochemistry and geodynamic setting of mineral resources in Serbia, Macedonia and Bulgaria 01.11.2009 SCOPES
111130 Metal transport and ore deposition: the geology, geochemistry and geodynamic setting of mineral resources in Bulgaria, Serbia-Montenegro and Romania 01.09.2005 SCOPES
116693 Metal transport and ore deposition: Quantitative modelling of magmatic-hydrothermal systems 01.04.2007 Project funding (Div. I-III)
128685 High-precision geochronology of ore-forming processes: partial funding for a Triton TIMS 01.12.2009 R'EQUIP

Abstract

This is a follow-up proposal to support the next two years of three PhD students and to obtain partial funding for a postdoc, as Parts A to D of our ongoing program linking four fields of research: analytical lab development, numerical modeling, integrated geological process quantification, and isotope geochemistry.A. Microanalytical technique development: sulphur in fluid inclusionsSulphur is arguably the most important chemical element in hydrothermal ore formation, but was so far not routinely measured in microscopic fluid inclusions. Collaborative technical developments in ETH’s Laser-Ablation-ICPMS laboratories have now established a viable approach for sulphur detection and quantification. In Jung Hun Seo’s PhD project, we will further optimise and apply this capability to understand the role of sulphur in magmatic ore fluids, notably its complexation of ore metals in high-salinity brine and low-salinity vapour at the porphyry to epithermal transition of magmatic-hydrothermal ore systems.B. Numerical modeling of two-phase fluid flow in hydrothermal systemsOur finite-element code CSMP++ has been developed for two-phase fluid (saline liquid + vapour) flow across the entire range from magmatic to surface conditions and from pure water to hydrous salt melts. By integrating geological and geochemical constraints from the broad range of ore deposits associated with arc magmas with numerical modeling, Postdoc Philipp Weis will study the influence of intrusion size and depth, rate of magmatic fluid release, volcano topography and the large-scale permeability structure of host rocks, to identify the first-order geological controls on the evolution of magmatic-hydrothermal systems and to explain the range of fluid evolution paths recorded by fluid inclusions.C. Integrated process model for the Bingham porphyry-Cu-Mo-Au systemOur modeling capabilities are ready to be linked with our extensive observational data for the giant Bingham Canyon porphyry-Cu-Mo-Au deposits, to build the first process-evolution model for a specific ore-forming magmatic-hydrothermal system. PhD student Ingo Steinberger is integrating geological and fluid-compositional constraints available from this deeply exposed orebody with an interpretation of the geometry of the subjacent magma chamber based on geophysical data provided by Rio Tinto. We will simulate fluid flow and thermal evolution for a range of hydrological scenarios, to identify the optimal conditions for economic porphyry mineralisation and to understand the typically zoned Cu-Au-Mo precipitation in the Bingham Canyon and in other porphyry-type orebodies.D. Geodynamics, geochronology and hydrothermal ore provincesCollaborative links with Bulgarian, Romanian and Serbian partners established within the completed European GEODE and the Swiss SCOPES coordination programs are continued by specific research to explore the relationships between lithosphere-scale geodynamics and ore formation in South-Eastern Europe. PhD student Melanie Moll is extending our research on igneous geochronology and geochemistry in Bulgaria to the previously inaccessible border region and the highly Cu-Au mineralised Timok Zone of Serbia. In addition to zircon geochronology and regional geochemistry, we will test new techniques for isotopic-geochemical tracing of growth zones and melt inclusions in zircon, as indicators of source characteristics of magmas and their mineralisation potential.
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