PETROGRAPHIC EXERCISES
Learning outcomes of the course unit
The mineral content and the textural relationships within the volcanic rocks are described in detail. Petrographic descriptions include megascopic description of hand specimens and the detailed analysis of minerals in thin section by using the petrographic microscope.The goals of the course are to provide a solid background on the various types of volcanic rocks and the knowledge needed for their appropriate classification.
Prerequisites
Mineralogy is propaedeutic
Course contents summary
Textures of the volcanic rock:
origin of the texture;
degree of crystallinity;
crystals shapes and size;
phase relationships (order of crystallization; intergrow and reaction textures);
types of texture.
Chemical composition of the volcanic rock:
SiO2 saturation;
Al2O3 saturation;
alkalinity.
Classification of igneous rocks:
normative composition;
Irvine-Baragar classification of volcanic rocks;
IUGS Classification of volcanic rocks;
Volcanic rock associations:
subalkaline rocks;
alkaline rocks;
ultra-alkaline rocks;
silica-poor alkaline rocks;
ultrapotassic rocks;
peralkaline rocks;
lamprophyres.
Recommended readings
E.W. Heinrich, Microscopic identification of minerals, McGRAW-HILL BOOK COMPANY
W. S. MacKenzie, C. Guilford, Atlante dei minerali costituenti le rocce in sezione sottile, Zanichelli
W. S. MacKenzie, C. H. Donaldson, C. Guilford, Atlante delle rocce magmatiche e delle loro tessiture, Zanichelli
W. A. Deer, R. A. Howie, J. Zussman, Introduzione ai minerali che costituiscono le rocce, Zanichelli
W. A. Deer, R. A. Howie, J. Zussman, Introduzione ai minerali che costituiscono le rocce, Zanichelli
