Igneous Petrology Jean-François Moyen

Practical informations Venues, dates, times Contact Textbooks Outline

1.Classification of igneous rocks 2.Analytical techniques; major and trace elements 3.Isotopes 4.Magma genesis: melting processes 5.Magma evolution: cristallization, mixing, etc. 6.Geochemical signature of mgmatic processes 7.Magma transport and emplacement 8.Volcanic processes

Outline 9.Basalts 10.Andesites 11.Granites 12.Alkaline complexes 13.Igneous rocks in a plate tectonic context 14.Revisions etc. April break: 2 days field trip

Introduction to igneous petrology

Stromboli (Italy)

Etna (Italy)

Piton de la Fournaise (Réunion, Indian Ocean)

Torres del Paine, S. Chile Ploumanac’h, France

Cantal extinct volcano, France

« Ignimbrites », Turkey

Bournac volcanic pipe, France

Montserrat, Lesser antilles (1997)

The upper part of the solid Earth Crust Oceanic Continental Mantle Lithosphere Astenosphere

The Pressure Gradient P increases =  gh Nearly linear through mantle ~ 30 MPa/km  1 GPa at base of ave crust Core:  incr. more rapidly since alloy more dense Figure 1-8. Winter, From Dziewonski and Anderson (1981). Phys. Earth Planet. Int., 25, © Elsevier Science.

Heat Sources in the Earth 1. Heat from the early accretion and differentiation of the Earth u still slowly reaching surface 2. Heat released by the radioactive breakdown of unstable nuclides

The Geothermal Gradient Figure Winter, from Green and Falloon ((1998), Green & Ringwood (1963), Jaupart and Mareschal (1999), McKenzie et al. (2005 and personal communication), Ringwood (1966), Rudnick and Nyblade (1999), Turcotte and Schubert (2002).

Active volcanoes

The Geothermal Gradient Pattern of global heat flux variations compiled from observations at over 20,000 sites and modeled on a spherical harmonic expansion to degree 12. From Pollack, Hurter and Johnson. (1993) Rev. Geophys. 31, Cross-section of the mantle based on a seismic tomography model. Arrows represent plate motions and large-scale mantle flow and subduction zones represented by dipping line segments. EPR =- East pacific Rise, MAR = Mid- Atlantic Ridge, CBR = Carlsberg Ridge. Plates: EA = Eurasian, IN = Indian, PA = Pacific, NA = North American, SA = South American, AF = African, CO = Cocos. From Li and Romanowicz (1996). J. Geophys. Research, 101, 22,

Figure 1-9. Estimated ranges of oceanic and continental steady- state geotherms to a depth of 100 km using upper and lower limits based on heat flows measured near the surface. After Sclater et al. (1980), Earth. Rev. Geophys. Space Sci., 18,

Plate Tectonic - Igneous Genesis 1. Mid-ocean Ridges 2. Intracontinental Rifts 3. Island Arcs 4. Active Continental Margins 5. Back-arc Basins 6. Ocean Island Basalts 7. Miscellaneous Intra- Continental Activity u kimberlites, carbonatites, anorthosites...

Plates and plate boundaries Geological activity is concentrated on plate boundaries