00799 - Petrography

Learning outcomes

Students will learn the basic tools to describe and classify igneous, metamorphic and silicoclastic rocks, and understand the petrogenetic processes and their geologic significance. Students will acquire the know-how to classify in the field (= outcrop scale) and in the lab (hand sample + thin sections) igneous, metamorphic and silicoclastic rocks

Course contents

Igneous rocks - The magma: physical and chemical features. Upwelling and solidification of magmas: intrusive vs. volcanic settings. Origin of mantle magmas. Magmatic differantiation: fractional crystallzation, gravitative setting and cumulus rocks, assimilation. Bowen's reaction series. The role of Pressure and fluids on the origin of magmas. Origin of anatectic magmas. Mixing and mingling of magmas. Mineralogical and chemical of igneous rocks. Classification of magmatic rocks. Trace element and isotopes to fingerprint magmatic sources. Magmatic series and their relation to different geodynamic settings.

Metamorphic rocks - The drivers: Pression, Temperature, Deformation and Fluids. Microstructures and their classification. How to classify a metamorphic rock. ;etamorphic reactions and the record they left into the rocks. Metamorphic grade and facies. Facies series. Geotherm and Pressure-Temperature-time paths. Regional metamorphism (orogenic and sea floor) and contact metamorphism. Analysis and interpretation of mineral assemblages in metabasites and metapelites.

Petrography of Sedimentary rocks - Wheathering, transport and deposition of sediments. Diagenetic processes. Structures, textures, composition and classification of clastic, carbonatic, evaporitic and derived from biological activity.

Lab activities - (Natural Sciences) Classification of hand-sized samples of igneous, metamorphic and sedimentary (silicoclastic) rocks. (Geological Sciences) Classification of hand-sized samples of igneous, metamorphic and sedimentary (silicoclastic) rocks and texture analysis of thin sections of igneous, metamorphic and sedimentary (silicoclastic) rocks by polarizing optical microscopy 

Field Trip - A single-day excursion with practical exercises of classification of igneous and metamorphic rocks

Readings/Bibliography

Klein C., Philpotts A. (2018) Mineralogia e Petrografia (1a ed. italiana), Bologna, Zanichelli.

D'Argenio F., Innocenti F., Sassi P.F. (1994) Introduzione allo studio delle rocce, Torino, UTET.

Teaching methods

Class lectures augmented by

• Petrography Lab
• Optical microscopy lab
• Field Excursion
  

Assessment methods

NATURAL SCIENCES

The final examination consists of a practical exam and an oral discussion

The practical exam is a written report that summarizes the observation and classification of two rock types (igneous and/or metamorphic) at the mesoscopic scale.

The candidate has to know how to use the QAPF diagram for plutonic and volcanic rocks and the Total Alkali vs. Silica diagram for volcanic rocks.

The oral discussion focuses on

1. Discussion of the written report
2. Questions on the main petrogenetic concepts presented during the class lectures
   

The final grade is the arithmetic mean of the grades obtained from the practical exam and the oral discussion.

GEOLOGICAL SCIENCES

The final examination consists of a practical exam and an oral discussion

The practical exam is a written report that summarizes the observation and classification of

a) two rock types (igneous and/or metamorphic) at the mesoscopic scale.

b) two rock types (igneous and/or metamorphic) at the micro scale

c) a sedimentary rock (silicoclastic and/or carbonatic) at the micro scale.

The oral discussion focuses on

1. Brief Discussion of the written report
2. Questions on the main petrogenetic concepts presented during the class lectures
   

Teaching tools

• Video Projectors supporting Power Point presentations
• Hand-sized samples
• Thin sections
• Polarizing Optical Microscopes
• Mineral and rock collections of the Museo di Mineralogia Luigi Bombicci
  

Office hours

See the website of Roberto Braga

See the website of Tommaso Giovanardi