Techniques of Geochemical Monitoring

Objectives

1. Understand the role of the geochemical monitoring in the scope of volcanic surveillance programmes.

2. Characterize the chemical composition of water in surface and groundwater bodies and to identify and describe the occurring geochemical processes.

3. Understand sampling and analytical procedures for natural waters and volcanic gases, and develop analytical work both in the field and in the laboratory.

4. Characterize the different degassing types found in volcanic/hydrothermal areas, and discuss possible factors that may interfere with the gas emissions.

5. Apply statistical methodologies to model (spatially and temporally) and interpret volcanic gas variations, as well as to recognize the origin of the gases emitted.

Program

1. Introduction to the geochemical monitoring: main objectives and methodologies; advantages and constrains

2. Notions of hydrogeochemistry

2.1. Types of dissolved constituents and suspended material in natural waters

2.2. Concept of activity, chemical equilibrium and saturation status

2.3. Chemical composition of natural waters and modifying chemical e biogeochemical reactions

2.4. Isotopic tools

3. Sampling and analysing natural waters

3.1. Methodologies of sampling and analyses in the field

3.2. Methodologies of analyses in the laboratory (potentiometric methods; titrations; atomic absorption spectrometry; ionic chromatography)

3.3. Graphic representation and hydrogeochemistry modelling

4. Volcanic gases

4.1. Types of degassing (fumaroles, diffuse degassing areas)

4.2. Origin of the gases

4.3. Factors that influence gas emissions on volcanic environments

5. Volcanic gases sampling and analyses in hydrothermal environments

5.1. Sampling strategies for gases from fumaroles and diffuse degassing areas

5.2. Analytical procedures and statistical tools

Teaching Methodologies

The concepts and knowledge of the basics of Techniques of Geochemical Monitoring are acquired throughout the course. Teaching is made through a combination of in-room activities, complemented by the on-line learning platform (Moodle) of the University of the Azores.

Theoretical and practical teaching of the Techniques of Geochemical Monitoring course is based in a succession of complementary classes of both types:

(a) Theoretical classes: based in MS Power Point presentations, with the development of selected case studies, when applicable.

(b) Practical classes: include the resolution of problems and development of water and gas analysis. Two field classes will take place in order to collect water and gas samples and develop several analytical methods.

Theoretical classes proceed to the explanation of the conceptual framework required to achieve didactic objectives, namely through the determination and association of geochemical characteristics of both water and gaseous phases with volcanic surveillance.

Natural waters and gas sampling techniques in volcanic/hydrothermal environments will be learned by the students through field classes, where students can apply the theoretical concepts and also recognize different methodologies used in volcanic monitoring. Collection and analyses of natural waters and gas emissions will contribute to consolidate the theory and to evaluate in situ the factors that may interfere with the chemical composition of the studied volcanic manifestations. Laboratorial classes will allow the students to obtain complete water and gas analyses, and understand their importance for volcanic surveillance. Practical classes on the classroom will be an opportunity to apply statistical and geochemical modelling tools (with different software) to understand the data collected during the field surveys.

On-line activities are planned in order to support the concepts developed in the theoretical classes, enhancing self-study, outside the class room.

Bibliography

Albarède, F. (2003) - Geochemistry. An Introduction. Cambridge University Press.

Appelo, C.A.J. & Postma, D. (1993) - Geochemistry, groundwater and pollution. Balkema, Rotterdam.

Drever, J.I. (1997) - The geochemistry of natural waters. Surface and ground water environments. Prentice Hall, Upper Sadle River.

Kehew, A.E. (2001) - Applied chemical hydrogeology. Prentice Hall, Upper Saddle River.

Langmuir, D. (1997) - Aqueous environmental geochemistry. Prentice Hall, Upper Sadle River.

Oppenheimer, C., Pyle, D.M. & Barclay, J. (Eds.) (2003) - Volcanic Degassing. Geological Society of London.

Rouwet, D., Christenson, B., Tassi, F. & Vandemeulebrouck, J., (Eds.) (2015) Volcanic Lakes. Advances in Volcanology, Springer, Berlin.

Selinus, O., Alloway, B., Centeno, J.A. et al. (Eds.) (2005) - Essentials of Medical Geology: Impacts of the Natural Environment on Public Health. Elsevier Academic Press.

Sigurdsson, H., Houghton, B., McNutt, S., Rymer, H. & Stix, J. (Eds.) (2015) - The Encyclopedia of Volcanoes (Second Edition), Academic Press.