75516 - VULCANOLOGIA E RILEVAMENTO DEL VULCANICO

Course Unit Page

Academic Year 2018/2019

Learning outcomes

The course gives to the students the main skills to understand the eruptive processes and to perform stratigraphic analysis and geological mapping of volcanic areas. In particular, the students are able to: - describe the main volcanic forms; - recognize the primary and secondary deposits in volcanic areas; - perform a detailed analysis and description of pyroclastic deposits and lava flows; - analyze and sample volcanic successions composed of several depositional units; - carry out grain size, petrographic and geochemical analyses.

Course contents

The course is arranged into different sections aimed at providing a general framework of knowledge on the structure of a volcano starting from its magmatic sources to the volcanic edifices on surface, and at defining the main eruption types and depositional mechanisms of the various volcanic products. I – MAGMA (roots of a volcano). Geodynamics and distribution of volcanoes on Earth. Origin, composition, ascent and chemical-physical evolution of magmas. Magma chambers. Dykes and eruptive conduits. Physical properties of magmas. II – EFFUSIVE VOLCANISM. Features and flow dynamics of mafic lava flows (pahoehoe and aa). Features and flow dynamics of silicic lavas: blocky lava flows, rhyolitic lava flows (coulees), volcanic domes. Explosive activity associated to the domes. Submarine volcanism. Submarine explosive activity. Evolution of a volcanic island. Subglacial volcanism. III - EXPLOSIVE VOLCANISM.  Classification of volcanic activity. Processes of magmatic fragmentation (volatile exsolution and magma/water interaction). Volcanic plumes and fall deposits. Pyroclastic density currents and related deposits. Volcanic deposits and eruption types. Morphology of the volcanic edifices. IV – VOLCANO-TECTONICS. Volcano-tectonic collapse structures (calderas and sector collapses). Mass gravity flows (debris avalanches, lahar). V - FIELD MAPPING IN VOLCANIC AREAS. Main concepts of stratigraphic analysis in volcanic areas (unconfomity-bounded units, lithostratigraphic units and lithosomes). Principles of geological fieldwork in volcanic areas and peculiar aspects of recent to active volcanoes. Description of the lithological, mineralogical and petrographical features of the volcanic deposits. Main concepts of tephrostratigraphy. Morphological factor (relationships between volcano-tectonic processes, regional tectonics and volcanic activity). Recognition of unconformities and stratigraphic correlations. Eruptive history of a volcano.

Teacher in charge: Dott. Federico Lucchi Collaborator teacher/s: Dott. Claudio Antonio Tranne.

The course is organized into 32 hours of frontal lessons (4 CFU) + 10 hours of practice exercises + 24 hours of field excursion for a total of 66 hours of didactic activity.

Readings/Bibliography

• Power Point lecture notes.

• R.A.F. Cas, J.W. Wright, 1987. Volcanic successions: modern and ancient. London Unwin Hyman.

• H. Sigurdsson (Ed.), 2000. Encyclopedia of Volcanoes. Accademic press, San Diego, U.S.A.

• M.J. Branney, P. Kokelaar, 2002. Pyroclastic density currents and the sedimentation of ignimbrites. Geological Society of London, Memoirs 27.

• H.U. Schminke, 2004. Volcanism. Springer-Verlag, Berlin Heidelberg.

  • R.V. Fisher, H.U. Schminke, 1984. Pyroclastic rocks. Springer-Verlag, Berlin Heidelberg.

Teaching methods

PowerPoint and/or Keynote presentations.

Recognition of volcanic rocks and deposits through hand samples or outcrop photographs.

The course takes advantage of a field excursion in Italian volcanic areas (Aeolian Islands, Mt. Etna and Vesuvio) aimed at verifying the learning of the concepts treated during the room lectures and at carrying out various activities of stratigraphic analysis and field mapping in volcanic areas.

Assessment methods

The assessment is aimed at verifying the knowledge of the student about the main aspects of volcanology, and the ability of recognizing volcanic deposits/ rocks and putting together the theory knowledge and data derived from the fieldwork.

The assessment method is based on written test relative to the theory sections, a mapping exercise during the field excursion and a confirmation oral exam.

Teaching tools

Video-projector.

Hand samples.

Office hours

See the website of Federico Lucchi

See the website of Claudio Antonio Tranne