Learning outcomes
The course provides an introduction to geochemistry and is aimed at undergraduate students who require an
appropriate understanding of basic chemical principles of geological processes. A quantitative approach of
geological processes using major and trace elements, as well as radiogenic and stable isotopes is stressed
wherever possible. The intent of the course is to familiarise students with the tools of geochemistry. These
include the tools of thermodynamics, kinetics, aquatic chemistry, trace element geochemistry, and isotope
geochemistry.
Course contents
Geochemistry of low temperature processes
Aqueous solutions in geology: The water cycle and the fundamentals of groundwater geochemistry. Main
hydrochemical parameters: temperature, conductivity, pH, Eh, alkalinity. Major cations and anions; the
electrical balance. Graphical representation of groundwater types: Piper, Schoeller and Langelier-Ludwig
diagrams. Ocean and continental waters.
Water-rock interaction phenomena: dissolution/precipitation, oxidation/reduction, ion exchange, carbonate and
silicate dissolution, saturation indexes, carbonate precipitation, evaporites, pyrite oxidation, ion exchange
phenomena.
Fundamentals of isotope geochemistry: Stable isotopes and their fractionation, the delta notation, stable isotopes
of the water molecule, the meteoric water line, isotope exchange. Carbon, Nitrogen and Sulfur isotopes and
their applications in geology. Radioactive isotopes and groundwater dating: Tritium and 14C.
Geochemistry of high temperature processes
Solutions and thermodynamics of multicomponent system: Phase equilibria. Phase equilibria. Ideal and real
solutions. Activity and activity coefficients.
Application of thermodynamics to the Earth: Thermodynamics and phase diagrams. Geothermometry and
geobarometry. Thermodynamics models of magmas.
Kinetics of geological processes: Disequilibrium textures. Reaction rate. Radioactive decay. Diffusion. Closure
temperature. Viscosity.
Elemento of geological interest. Major and trace elements. Light Lithophile Elements (LLE), Large Ion
Lithophile Elements (LILE), 3d Transition elements. High Field Strength Elements (HFSE), Rare Earth
Elements (REE), Platinum Group Elements (PGE). Solar system abundance of the elements. Meteorites.
Trace elements in igneous processes: Goldschmidt’s classification of the elements. Classification of trace
elements depending on their geochemical behaviour. Compatibile and incompatibile elements. Partition
coefficients. Factors governing the value of partion coefficients.The role of crystal-chemical control. Onuma
diagrams. Trace element distribution during melting and crystallisation. Fractional melting and the origin of
MORB melts.
Geochronology and radiogenic isotope geochemistry: Nucleus and its structure. Distribution of stable nuclei.
Radioactive decay and geochronology. Argon methods. The Rb-Sr system. The Sm-Nd system. The U-Th-Pb
system. U-Pb dating of zircons. Common Lead. Radiogenic isotopes in petrogenesis.
Stable isotopes: Delta notation. Isotope fractionation. Physics and chemical controls on stable isotope
fractionation. O and H isotopes in rocks and minerals. B and Li isotopes. Thermometry. Water-rock interaction.
Laboratory exercises. Using trace elements in the petrogenetic interpretation. Using radiogenic isotopes in
geochronology and as markers of geological processes. Using stable isotopes in thermometry and as
fingerprinting of water-rock interaction.
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