magmatic phenomena Turkey – June 2014 project from italy

1. magmatic phenomenaTurkey – June 2014 project from italy

2. MAGMA - DEFINITION • It’s a complex and heterogenousmolten rock system • The physical state isprevalentlyliquid • Itcontainsgases(water vopour, carbon dioxide, hydrogen) • It’s composed by a large number of minerals, mainlysilicates • It’s formed inside the litosphere, at a dephtbetween 50km to 250-500km • From the solidification of magma, magmatic and igneousrocks are formed • When magma comes out on the surface and totally or partiallyloses the gassespresentwithinit, itturns in lava • It’ classified on the basis of the quantity of silica or silicadioxidepresent in it • On the basis of the percentage of silica, fourbasictypes of magma can be listed: • Acid Magmas • NeutralMagmas • MalficMagmas • UltramalficMagmas

4. PLUTONISM • It’s a magmaticphenomenon • It consists in a slow solidification of magma deep in the lithosphere • Typical of acid magmas, viscous and not very hot • The gathering of these underground rocky masses is called pluton. It is not visible from the earth surface until a geological phenomenon opens a tectonic window • Often close to plutons there are veins of precious metals • Formation of intrusive magmatic rocks formed by large perfect crystals

5. VOLCANISM It is a magmaticphenomenonthatoccorswhen magma solidifies on the terrestrialsurface. Volcanism’sresultis the volcano. CRATER SECONDARY CRATER SECONDARY CONDUIT CONDUIT TERRESTRIAL SURFACE MAGMATIC CHAMBER

6. TYPES OF VOLCANO • The eruptive activity of a volcano (and many other characteristics such as its dimensions, its form...) is determined by the characteristics of its magma. • These characteristics are its temperature and its chemical composition (concentration of H2O and silicates). • It's possible to classify volcanoes in 2 big groups: Explosive and Effusive Volcanoesaccording to their eruptive modality, that is according to the type of erupted magma

8. VESUVIO Characterictics of volcanoes with esplosive eruption Esplosive volcanoes generally emits andesitic lava, viscous enough not to form streams of lava It forms dome shaped peaks of accumulated lava on the eruption mouth When the mass of lava accumulated collapses, an eruptive column of gasses, ash and lapilli erects over the volcano They are mainly located where the continental plaques collides with each other During the eruption they can destroy themselves forming a volcanic caldera Important eruption of the Vesuvio 79 DC - A very violent explosive eruption took place. That caused the collapse of one of the mountain's sides where the current crater is located. The stream of lava destroyed the Roman city's of Pompeiand Ercolano. The last eruption took place in 1944, since then the volcano has been quiet

10. ETNA • Definition • The magma is basic and the lava is fluid and basaltic, the eruption is of the Hawaiian type. • Behavior effusive and rarely explosive due to abundant gas emissions of steam. • It is a shield volcano, it has moderately steep sides, the • crater is characterized by low slope cones. • Erupts at times fairly close together, initially with a degassing phenomena and emissions of volcanic sand, followed by the emission of lava. • Famous eruptions • 1669 → It was the Etna’s most destructive eruption. It destroyed most of the city of Catania and it created more than 1km of new land. It lasted 122 days and emitted 950 million m3 of lava. • 1991 → It was the longest eruption of the twentieth century. And it lasted 473 days

12. Effusion magmaticrocks • Typof magmatic and igneousrocks • Theysolidify on top of the earth’scrust with a rapiddrop in pressure and temperature • AmorphouscrystalsmcalledPhenocrysts are formed

13. Intrusive MAGMATIC Rocks Definition • Type of magmaticrocks • The consolidation take place in depth with a slow diminuition of pressure and temperature • Big and pure crystals are formed; they've a perfect structure calledholocrystalline GRANITO GABBRO

14. Liquid secondary magmatic phenomena Geyser • In the subsoil permeable rocks (which form the water conduits) are surrounded by waterproof rocks. A pocket of magma is close to it, the trapped water, despite the high temperature, can't evaporate because of the pressure caused by the rocks. • There are two types of geysers: conical geysers (which erupt from a silicon made cone) and fountain geysers (erupting from a lagoon). • Eruptions take place after a sequence of events: • The water conduits fill up with water from the outside and from the aquifers, the higher the pressure the greater the force with which the water erupts. • The heat from the magmatic chamber increases the temperature and the pressure of the water. • The eruption starts when the water starts to boil, the pressure forces upwards water and vapor and dissipates very quickly. • A mew eruptive event starts when the water conduits fill up again. • In Italy there are some small geysers in lake Naftia (Sicily), Fiumicino (near Rome) and in the Valle del Diavolo ( Tuscany).

16. Liquid secondary magmatic phenomena Springs • Hot water sources rich in mineral salts. • Rain water penetrates in the soil. • Penetrating deep in the ground the water gets filtered and purified, different types of salts and gasses dissolve depending on the type of rocks. • The deeper the water is the more pure it becomes • When the water meets a waterproof layer it forms an aquifer. • These aquifers heat up and rise to the surface. • These waters are rich in mineral salts and are used for therapeutic treatments. • An example in Italy is Abanospirngs

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