Metallogenesis and Ore Minerals
A.Y. 2023/2024
Learning objectives
The course has two main goals. The first one is the acquisition of basic knowledge of the geological, mineralogical and geochemical features of the numerous mineral deposits, rich in critical metals and minerals, which can form via hydrothermal processes. The second goal is to provide the ability to identify assemblages of metallic (sulfides, sulfosalts, oxides and alloys) and gangue minerals by reflected light/metallographic microscopy and by observation of hand specimens from the main types of mineral deposits. This activity will focus on economic minerals, also known as "ore minerals". It will be possible to verify how the optical characters of minerals and their microtextures (possibly paired with additional analytical facilities) may provide preliminary, yet significant indications about conditions of deposition of mineralization, or even be useful for further evaluating either the economic value of an orebody and/or the consequences of a bad management of mining waste.
At the same time the students will learn how to identify the accessory "opaque" minerals hosted in common rocks. Opaque minerals are often sensitive to chemical-physical conditions in magmatic or metamorphic processes or may suggest the sources of rock components. Moreover, opaque minerals can be true "ore minerals" (e.g., Ti oxides) or else be cause of damage in commercial ornamental stones (e.g., fine-grained accessory pyrite in stone slabs for outdoor paving).
At the same time the students will learn how to identify the accessory "opaque" minerals hosted in common rocks. Opaque minerals are often sensitive to chemical-physical conditions in magmatic or metamorphic processes or may suggest the sources of rock components. Moreover, opaque minerals can be true "ore minerals" (e.g., Ti oxides) or else be cause of damage in commercial ornamental stones (e.g., fine-grained accessory pyrite in stone slabs for outdoor paving).
Expected learning outcomes
At the end of the course the student should be able to:
(a) possess some knowledge about the mechanisms of formation for the main types of hydrothermal ore deposits and about the methods for investigating them. Such knowledge may be useful either for further research on ore deposit modeling or for a possible work in a mining company involved in mineral prospecting;
(b) identify, by means of reflected light microscopy, numerous metallic minerals of economic value for industry and associated precious metals (Au, Ag, PGE) and gangue minerals;
(c) recognize the mineral assemblages and micro-textures typical for the main types of mineral deposits formed in a wide range of geological conditions, from high to low temperature and in deep, magmatic to suficial-marine-exhalative/diagenetic contexts;
(d) derive useful information about the chemical-physical conditions of ore deposition from the optical and microtextural features of ore and gangue minerals;
(e) have a basic knowledge for contributing to the mineralogical and chemical characterization of the different portions of an orebody towards a rational planning of its mining exploitation and, last but not least, of the management of related toxic mining waste;
(f) rapid identification of the accessory opaque minerals in common rocks often useful to better understand the "history" of their host rocks or else to better evaluate an adequate employment of commercial ornamental stones.
(a) possess some knowledge about the mechanisms of formation for the main types of hydrothermal ore deposits and about the methods for investigating them. Such knowledge may be useful either for further research on ore deposit modeling or for a possible work in a mining company involved in mineral prospecting;
(b) identify, by means of reflected light microscopy, numerous metallic minerals of economic value for industry and associated precious metals (Au, Ag, PGE) and gangue minerals;
(c) recognize the mineral assemblages and micro-textures typical for the main types of mineral deposits formed in a wide range of geological conditions, from high to low temperature and in deep, magmatic to suficial-marine-exhalative/diagenetic contexts;
(d) derive useful information about the chemical-physical conditions of ore deposition from the optical and microtextural features of ore and gangue minerals;
(e) have a basic knowledge for contributing to the mineralogical and chemical characterization of the different portions of an orebody towards a rational planning of its mining exploitation and, last but not least, of the management of related toxic mining waste;
(f) rapid identification of the accessory opaque minerals in common rocks often useful to better understand the "history" of their host rocks or else to better evaluate an adequate employment of commercial ornamental stones.
Lesson period: First semester
Assessment methods: Esame
Assessment result: voto verbalizzato in trentesimi
Single course
This course can be attended as a single course.
Course syllabus and organization
Single session
Responsible
Lesson period
First semester
Course syllabus
The course aims to introduce the students to the broad spectrum of topics
regarding ore deposits related to hydrothermal processes and considered
important hosts for critical metals and minerals. The teaching is done together with training on microscopy and identification and evaluation of both ore and gangue minerals from a variety of mineral deposits, as well as of opaque accessory minerals in unmineralized host rocks.
Topics of the course:
- Introduction to ore microscopy and ore petrography.
- Hydrothermal metallogeny at high temperature conditions: mineral deposits
associated with granitoid intrusions (high temperature veins, greisen, skarn); ore and gangue minerals and relative microtextures.
- Introduction to high-temperature mineralization of metasomatic, IOCG type
and associated with peralkaline magmas (anorogenic granites, carbonatites).
- Gold-bearing mesothermal mineral deposits: features, components and
emplacement modes in Archean to Phanerozoic orogenic contexts. Ore minerals (sulfides, alloys) and related microtextures.
- General features and types of geological fluids and their role in the concentration of economic metals and minerals. Introduction to hydrothermal alteration phenomena. Methods of study and geochemical analysis of mineral deposits for characterization of minerals and fluids, geo-thermo-barometry, geochronology.
- Magmatic-hydrothermal sulfide-rich porphyry-copper deposits and Au-Hg-Sb-bearing epithermal deposits related to both porphyry and geohermal systems.
- Cobalt, introduction to the Co-bearing deposit types of high- to low-temperature conditions, and relative ore minerals.
- Ore minerals and microtextures from Fe-Ni-Co sulfide-PGE- and/or
chromite-bearing ultramafic magmas and rocks (komatiites, basic-ultrabasic intrusions, ophiolite complexes).
- Submarine exhalative mineral deposits, of both volcanogenic (Cu-Zn-Pb-Fe
sulfides) and sedimentary-exhalative (Zn-Pb-Ag-Cu sulfides) types, with a focus on their transformations during orogenic processes.
- Ore minerals and microtextures from mineral deposits generated by "basinal
brines"/diagenetic-type fluids, with a focus on Mississippi-Valley-Type,Zn-Pb-Ba-F-bearing mineralization.
regarding ore deposits related to hydrothermal processes and considered
important hosts for critical metals and minerals. The teaching is done together with training on microscopy and identification and evaluation of both ore and gangue minerals from a variety of mineral deposits, as well as of opaque accessory minerals in unmineralized host rocks.
Topics of the course:
- Introduction to ore microscopy and ore petrography.
- Hydrothermal metallogeny at high temperature conditions: mineral deposits
associated with granitoid intrusions (high temperature veins, greisen, skarn); ore and gangue minerals and relative microtextures.
- Introduction to high-temperature mineralization of metasomatic, IOCG type
and associated with peralkaline magmas (anorogenic granites, carbonatites).
- Gold-bearing mesothermal mineral deposits: features, components and
emplacement modes in Archean to Phanerozoic orogenic contexts. Ore minerals (sulfides, alloys) and related microtextures.
- General features and types of geological fluids and their role in the concentration of economic metals and minerals. Introduction to hydrothermal alteration phenomena. Methods of study and geochemical analysis of mineral deposits for characterization of minerals and fluids, geo-thermo-barometry, geochronology.
- Magmatic-hydrothermal sulfide-rich porphyry-copper deposits and Au-Hg-Sb-bearing epithermal deposits related to both porphyry and geohermal systems.
- Cobalt, introduction to the Co-bearing deposit types of high- to low-temperature conditions, and relative ore minerals.
- Ore minerals and microtextures from Fe-Ni-Co sulfide-PGE- and/or
chromite-bearing ultramafic magmas and rocks (komatiites, basic-ultrabasic intrusions, ophiolite complexes).
- Submarine exhalative mineral deposits, of both volcanogenic (Cu-Zn-Pb-Fe
sulfides) and sedimentary-exhalative (Zn-Pb-Ag-Cu sulfides) types, with a focus on their transformations during orogenic processes.
- Ore minerals and microtextures from mineral deposits generated by "basinal
brines"/diagenetic-type fluids, with a focus on Mississippi-Valley-Type,Zn-Pb-Ba-F-bearing mineralization.
Prerequisites for admission
In order to get the most from this course (as others in the master degree), I think it is necessary to have or else to refresh the basic notions from the B.Sc. degree, i.e., mineralogy, petrography, geology in a wide sense, and, definitely, geochemistry. This is because this course is rather multi-disciplinary, actually like any other course dealing with mineral resources.
Then, of course, it is highly preferable if one already attended other courses on mineral resources, like, for example Raw Materials and Industry (optional, 3rd year B.Sc. in Geology) or else the course Mineral Deposits and Sustainability (optional, M.Sc. Earth Sciences) and, why not, also a quite useful course with upgrade in geochemistry, like Analysis of Rocks, Minerals and Fluids (optional, M.SC. Earth Sciences).
Then, of course, it is highly preferable if one already attended other courses on mineral resources, like, for example Raw Materials and Industry (optional, 3rd year B.Sc. in Geology) or else the course Mineral Deposits and Sustainability (optional, M.Sc. Earth Sciences) and, why not, also a quite useful course with upgrade in geochemistry, like Analysis of Rocks, Minerals and Fluids (optional, M.SC. Earth Sciences).
Teaching methods
The course (6 CFU, 48 hours) consists of 16 hours of lecturing and 48 hours of practicals (with ore microscopy and, subordinately, hand specimens), occasionally with mixed activity, i.e. with one hour lecturing followed by two hours of practicals on the topic of the day. Lectures and practicals are held in a classroom where the reflected light microscopes and the hand speciments used in the course are stored. During the whole course the interaction between the lecturer and the students and inbetween students and the discussions are quite intense and continuous. At least two turns of practicals with guided review are planned, one in the middle and one at the end of the course.
Teaching Resources
Hand-outs and teaching material provided by the lecturer; selected papers
from international journals and material from websites (e.g., geological
surveys, universities, mining companies, etc.).
Reference books for ore microscopy:
- Ramdohr P., Ore minerals and their intergrowths, Pergamon Press.
- Craig JR & Vaughan DJ, Ore microscopy and ore petrography, Wiley - free legal download here (*).
- Venerandi I., Corso di Minerografia, Ed. Cortina.
-Neumann U., Guide for the microscopical identification of ore and gangue materials (free download from the author here: http://dx.doi.org/10.15496/publikation-1274 or via Researchgate)
Useful for refreshing petrography at the microscope: Raith et al., Guide to Thin Section Microscopy: free legal download here (*)
(*) http://www.minsocam.org/msa/openaccess_publications/#Guide
Reference books for mineral deposits and hydrothermal processes:
- Pirajno F., Hydrotermal processes and mineral systems, Springer.
- Robb L., Introduction to ore-forming processes, Blackwell.
- Taylor R., Ore textures-Recognition and
interpretation, Springer.
from international journals and material from websites (e.g., geological
surveys, universities, mining companies, etc.).
Reference books for ore microscopy:
- Ramdohr P., Ore minerals and their intergrowths, Pergamon Press.
- Craig JR & Vaughan DJ, Ore microscopy and ore petrography, Wiley - free legal download here (*).
- Venerandi I., Corso di Minerografia, Ed. Cortina.
-Neumann U., Guide for the microscopical identification of ore and gangue materials (free download from the author here: http://dx.doi.org/10.15496/publikation-1274 or via Researchgate)
Useful for refreshing petrography at the microscope: Raith et al., Guide to Thin Section Microscopy: free legal download here (*)
(*) http://www.minsocam.org/msa/openaccess_publications/#Guide
Reference books for mineral deposits and hydrothermal processes:
- Pirajno F., Hydrotermal processes and mineral systems, Springer.
- Robb L., Introduction to ore-forming processes, Blackwell.
- Taylor R., Ore textures-Recognition and
interpretation, Springer.
Assessment methods and Criteria
The exam consists of a first written test followed by a rather short interview. The written test lasts 4 hours. It generally takes place after 4-5 days of free activity where the students review all the samples examined during the course with their own microscope. These 4-5 days are not compulsory but considered useful by most students, who generally either work independently or work and discuss together, while I come and check every now and then or if there is a problem.
The written test consists of the description, in proper language, of two samples (polished sections) of "unknown" ore deposits. The students have to identify and describe the minerals (at least the major ones, but preferably also the best visible accessory phases) and their textures and eventually propose a possible genesis, conditions of formation or type of mineralization, in the same way as done during the long time spent together in the practicals. During the written test the student can consult reference manuals, personal notes and schemes prepared during the course.
The (short) interview after the positive written test is meant to verify the basic knowledge about the types of ore deposits and the hydrothermal process by means of 2-3 questions.
The written test will provide up to 10 scores (starting from 18/30), while additional scores, up to 30/30 with distinction, can be gained with a positive interview. A highly negative interview is going to erode the scores gained with the written test.
The written test consists of the description, in proper language, of two samples (polished sections) of "unknown" ore deposits. The students have to identify and describe the minerals (at least the major ones, but preferably also the best visible accessory phases) and their textures and eventually propose a possible genesis, conditions of formation or type of mineralization, in the same way as done during the long time spent together in the practicals. During the written test the student can consult reference manuals, personal notes and schemes prepared during the course.
The (short) interview after the positive written test is meant to verify the basic knowledge about the types of ore deposits and the hydrothermal process by means of 2-3 questions.
The written test will provide up to 10 scores (starting from 18/30), while additional scores, up to 30/30 with distinction, can be gained with a positive interview. A highly negative interview is going to erode the scores gained with the written test.
GEO/09 - MINING RESOURCES, MINERALOGIC AND PETROGRAPHIC APPLICATIONS FOR THE ENVIRONMENT AND FOR CULTURAL HERITAGE - University credits: 6
Practicals: 48 hours
Lessons: 16 hours
Lessons: 16 hours
Professor:
Moroni Marilena
Professor(s)