Geochemistry

Code:

MEMG0015

Acronym:

GQ

Keywords
Classification	Keyword
OFICIAL	Mathematics, Physics, Earth Sciences

Instance: 2009/2010 - 1S

Active?	Yes
Responsible unit:	Mining Engineering Department
Course/CS Responsible:	Master in Mining and Geo-Environmental Engineering

Cycles of Study/Courses

Acronym	No. of Students	Study Plan	Curricular Years	Credits UCN	Credits ECTS	Contact hours	Total Time
MEMG	7	Plano de estudos oficial a partir de 2008/09	2	-	6	56	162

Teaching language

Portuguese

Objectives

These are the aims of each of the following four modules:

I – General introduction to Geochemistry
To be familiar with the geochemical classification of elements and understand the intimate association between the main geospheres (atmosphere, hydrosphere, crust, mantle and core) and the primary geochemical differentiation of elements. To compare the geochemical affinity of an element concerning the different types of mineral phases (silicated, sulphurated, Fe-Ni metal alloys) and planetary differentiation by density.
To relate the basic notions of:
- Major, minor and trace elements;
- Clarke and Clarke of concentration;
- Abundance and availability of elements.

II - Basic concepts of magmatic rocks geochemistry
From the concepts of magmatic differentiation, suite and magma series, students should understand the basic methodologies of variation diagram design to verify if a suite can constitute a magma series.
By using software available on the Internet, students should design variation diagrams for magmatic suites and classify magma series.

III – Geochemistry of supergen environments
To understand the chemical disequilibrium of materials of endogenous origin when exposed to superficial environments. To be familiar with the main types of supergen reactions of endogenous paragenesis alteration.

IV- Geochemical exploration
To be familiar with the fundamentals of geochemical exploration and then decide the application of this method.

Program

1st PART – General introduction to Geochemistry

I – Introduction
- Fundamental objectives of Geochemical investigation: relative and absolute determination of element abundances in the different geospheres and corresponding distribution and migration.
II – Meteorites
- Types of meteorites
- Meteorites as fundamental material in the study of earth composition
III – Composition of earth’s crust
- Concept of major, minor and trace elements
- Abundance of elements in earth’s crust
- Factors which control element availability
IV- Global composition of the earth
- Models of primary geochemical differentiation of elements.
- Main types of mineral phases of pre-planetary material: Fe-Ni alloys; sulphur phases and silicate phases.
- Determination of geochemical affinity of the diverse elements concerning each mineral phase.
- Geochemical classification of elements (Goldschmidt): siderophile, chalcophile, lithophile, atmophile.
- Factors of geochemical differentiation of earth’s elements: elementary affinity and density of mineral phases.

2nd PART - Magmatic rocks geochemistry
V- Chemical composition of magma and igneous rocks.
- Chemical composition of magmatic rocks analysed based on oxide frequency curves of major elements.
- Correlation diagrams and variation diagrams.
VI – Suites and Magma series
- Rock association in volcanic regions: accidental or not?
- Bowen magma series or differentiation series.
- Genetic relationship between magma series.
VII – Use of discriminatory geochemical standards
- Characteristic multielementary diagrams of diverse goetectonic contexts.

3rd PART - Geochemistry of supergen environments
VII – Chemical modification of rocks on earth’s surface. Processes of chemical meteorization.
- Verification of rock change by supergen agents: at a massif, outcrop and sampling level.
- Description of chemical changes. Types of processes. Common chemical reactions: Dissolution; Hydration; Hydrolysis; Acid-base; Oxidation-reaction.
- Meteorization products: common minerals in sedimentary rocks; Solute; Anion; Inorganic complex; Coloid.
- Physic-chemical factors of chemical meteorization: Ionic potential; Hydrogen-ion concentration; Oxidation-reduction potential;
- Sedimentary geochemical differentiation.

4th PART – Applied Geochemistry: Geochemical Exploration
IX – Theoretical basis to geochemical exploration works
- Geochemical abundance of elements. Concept of geochemical province. Geochemical background and geochemical anomalies. Case studies.
X- Geochemical exploration
- Main stages: Collection of pre-existing data and study of regional geological models; Sampling; Geochemical analysis; Processing and cartographic implantation of results; Results interpretation.
- Interpretation of geochemical anomalies.
- Study of geochemical dispersion halos; Case studies.

Teaching methods and learning activities

Classes run on a traditional basis, being theoretical themes presented in theoretical practical classes. Practical classes are based on case studies, tutorial of software and analysis of results.

Evaluation Type

Distributed evaluation with final exam

Eligibility for exams

Students have to attend 75% of the classes.

Calculation formula of final grade

Average grade of a monograph (50%) and a final exam (50%).

Special assessment (TE, DA, ...)

Students with special status are assessed as regular students, therefore they have to write a monograph and attend a final exam.

Classification improvement

Students may improve their grades by attending an exam at the corresponding season. Final grade will be based on average grade of both components (monograph and exam).