70728 - PETROGRAFIA

Learning outcomes

At the end of the course, the student has skills related to the genesis, composition and structures of the magmatic, sedimentary and metamorphic rocks and knowledge of the marbles, granites, porphyries and stones that have been used in historical times. In particular, the student is able to: - classify, according to the international classification schemes, the main rock types used in the cultural heritage; - understand, on the basis of the mineralogical-petrographic and structural characteristics, the state of freshness/alteration of the used materials; - to trace, through direct observation of monuments, the nature of the materials and their origin.

Course contents

What is the petrography: aims and methods of the study.

What is a rock, the rock cycle and the main petrogenetic processes. Brief summary of the main rock-forming minerals.

Igneous rocks: characteristics of silicate magmas, their crystallization and evolution within (intrusive igneous rocks) or on the surface (extrusive igneous rocks) of the Earth. Recognition of minerals and structures at the hand scale. IUGS classification (QAPF diagram).

Sedimentary rocks: general subdivision: clastic rocks, chemical and biogenic. Classification schemes and recognition of components and structures at the hand scale. Metamorphic rocks: metamorphic process control factors, types and degrees of metamorphism. Classification schemes and recognition of minerals and structures at the hand scale.

Petrographic study in the laboratory: the use of polarized light microscope, what is a thin section, recognition of the major minerals and the effects of the alteration.

The UNI EN 12407: Petrographic descriptions of natural stones.

The main ancient and modern natural stone used in historical and monumental building.

Igneous rocks: Granite, Tonalite, Syenite, Diorite, Gabbro, Trachite, Andesite, Basalt, Porphyry.

Sedimentary rocks:

of clastic origin: Conglomerate, Breccia, Sandstone, Clay.

of chemical origin: Gypsum, Travertine, Alabaster, Limestone.

organogenic: Calc-rudite, Calc-arenite, Calc-lutite.

Metamorphic rocks: Slate, Phyllite, Serpentinite, Marble, Mica-schist, Gneiss, Amphibolite.

Readings/Bibliography

Introduzione allo studio delle rocce, D'Argenio, Innocenti e Sassi, UTET Torino, 1994

Introduzione alle petrografia ottica (con CD-ROM), Peccerillo A. e Perugini D., Morlacchi ed., 2003

Pietre e marmi antichi, Lazzarini L., CEDAM Padova, 2004.

Power point delle lezioni.

Teaching methods

Lectures.

Individual and collective work on rocks and thin sections.

Group project.

Guided visits to sites of historical-artistic and architectural interest, employing natural stone materials.

Assessment methods

The learning assessment is through a three-hour practice test (Plutonic, Volcanic, Metamorphic and Sedimentary rocks) and a final oral examination. The practice test seeks to ascertain the skills acquired in the study and classification of rocks. Is evaluated through a judgment which must be positive to allow access to the oral test. The period of validity of the written test exceeded is limited to a single session of exams. The oral exam aims to test knowledge acquisition under the program of the course with additional purpose of verifying the learning of the alteration processes of the rocks. The final score, expressed in thirtieths, takes into account the grade achieved in both tests.

Teaching tools

Rocks and petrographic thin sections.

Stereo Microscopes and optical polarizers.

Web resources (eg. . Geogallery)

Office hours

See the website of Giuseppe Maria Bargossi