Magmatism and Volcanism

Abstract

The generation and evolution of igneous rocks as products of geodynamic processes operating within the Earth's interior.

Objective

This lecture combines petrography, geochemistry, experimental and theoretical petrology to assess fundamental processes controlling the generation and differentiation of igneous rocks in time and space. Principle targets are the generation of magmas in the Earth upper mantle and crust, differentiation and emplacement of magmas at depth and on the surface. The most prominent volcanic and plutonic rock series are presented and their relationships in the framework of global tectonics are discussed. The material is mostly presented in qualitative way. However, a quantification of igneous processes basing on modal mineralogy, geochemistry, phase petrology and thermodynamic principles is assessed on simple examples in the lectures and in part of the accompanying practicals. Basic knowledge of rock-forming minerals and the classification of igneous rocks are required and will be further trained during the praticals.

Content

Introduction – Historic evolution – Magmatism-Tectonics Igneous Petrology and thermodynamics – Some basic principles Representation and normalization of igneous minerals and rocks Physical properties of magmas and emplacement mechanisms Binary and ternary liquidus phase diagrams (principles and basaltic systems) Physical volcanology - Tephra vs. lava Tholeiitic magmatism 1 – MORB and flood basalts Tholeiitic magmatism 2 – Layered Intrusions Partial melting in the Earth upper mantle Geochemistry in igneous petrology Subduction magmatism (magmatism at convergent plate margins) Calc-alkaline volcanism (Cascadian volcanoes) Calc-alkaline plutonic rocks (Adamello batholith) Alkaline intraplate magmatism Liquidus phase diagrams for felsic systems: Feldspars – SiO2 – feldspatoids CO2-rich magmas: Kimberlites, organeites and carbonatites Volcanism versus plutonism: The role of H2O during melting and crystallization of basalt and granite under elevated pressures

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