Geochemistry of natural environment

obligatory courses

The lecture includes three parts. The first part features general geochemistry and cosmochemistry issues: stellar and cosmic nucleosynthesis, the elemental diversity of geospheres and its causes. The second part focuses on chemical compounds of the outer geospheres, with particular emphasis on lithosphere. The processes of primary and secondary minerals formation, weathering of rocks-forming minerals are presented. The third part is devoted to detailed geochemical characteristics of 12 selected elements hazardous to both animals and humans (e.g., Cd, Al, As, Be, Tl). In that respect geochemical anomalies recognized and mapped in Poland, processes of elements extraction and also examples of application of geochemical research (geochemical prospection, conservation and restoration of historical buildings, asbestos and other geohazards).

PART I

Geochemistry as a branch of geosciences

Fundamentals of cosmochemistry

a) nucleosynthesis: hot fusion, stellar thermonuclear processes, neutron capture

b) meteorites – source of data on the Earth origins and its chemical composition

c) formation of the Earth

Energy flow in the Earth, the periodic table of elements, the Goldschmidt’s geochemical classification of elements and its modifications, categories and modes of elements occurrences, diadochy, isomorphic and geochemical dispersion.

Element abundances in the Solar System and geospheres; chemical composition of geospheres – similarities and differences.

PART II

Oxidation of elements, oxidation-reduction (redox) potential, typical chemical compounds of biosphere, atmosphere and lithosphere: minerals and their physical properties, primary and secondary minerals, behaviour of Al2O3 and SiO2 in various geochemical environments, clay minerals and their significance in natural environment.

Weathering processes: types of weathering and accompanying processes, mechanisms of chemical weathering of rock-forming minerals (feldspars, micas, Fe-Mg silicates), weathering products – their chemical composition, transport and sedimentation.

PART III

Short history of element usage in human civilisations, the extraction of elements, element reserves, toxic elements and environmental pollution (migration of pollutants).

Geochemical characteristics of selected elements (As, Cu, Ni, Be, Tl, Pb, Zn, Cd, Cr, Co, F, Al, F): occurrences of an element and its main minerals, chemical forms (compounds) in natural environment (hypergene zone), element mobility and retention in environment (soils, water sediments, watercourses), principal usage of an element, significance of an element in life of humans and animals, element toxicity, natural and anthropogenic anomalies of an element in Poland (soils, water sediments, surface waters) and their origin.

Geochemical prospection: geochemical anomaly, geochemical and mineral aureole, primary and secondary aureole, biogeochemical and geobotanic methods of prospection.

Asbestos and other geohazards.

Aim:

Understanding fundamental processes and mechanism governing the distribution, cycling, mobility and retention of elements, formation and decay of natural chemical compounds in the environment (Earth’s crust and hypergene zone). Learning to perceive the natural environment, on the planet scale and in the accessible geospheres, through the geochemical processes and phenomena.

Efect:

The student comprehends the formation of primary and secondary chemical compounds of the lithosphere (rock-forming minerals), and is familiar with detailed, individual characteristics of selected elements. Using his or her knowledge, the student understands and is able to predict the behaviour and migration of chemical elements in a given portion of the natural environment, with particular reference to toxic elements or elements hazardous to humans under specific conditions. The student knows and understands the origin of formation of geochemical anomalies in Poland, both natural and anthropogenic. Consequently, the student is able to undertake the evaluation of environmental impact of a given element and changes of geochemical properties of a selected portion of the natural environment induced by economic activity. The student is able to predict the impact of changes in physico-chemical parameters on geochemical properties of a given area. He or she is also familiar and aware of hazards imposed by natural substances, such as asbestos, silica dust and other mineral dusts, vog, etc.

he credit is given on two element-basis:

1) final assignment completed individually or in teams of 2, covering the issues studied during the exercises - 33% of the grade;

2) final test (conducted on-site via the Kampus digital platform) containing open-ended questions, supplementary questions and multiple-choice questions, writing time 45 minutes - 67% of the grade.

The condition for passing with a positive grade is obtaining a minimum of 50% of the test available value and a minimum of 50% of the overall grade combining both assessed elements according to their weight.