Volcanoes are fascinating and dangerous. Welcome to a journey into the world of volcanic activities and rock forming processes.
The course will start with some basics: A definition of a volcano and, based on mineralogy and geochemistry, simple nomenclature systems for volcanic rocks will be presented.
The recognition of the distribution of volcanoes on the earth’s surface, in respect to the plate tectonics, leads to three general scenarios of the location of volcanoes: at destructive plate margins (subduction zones), at constructive plate margins (mid ocean ridges), and within plates, both oceanic and continental (hot spots, rifts, and other).
The basic two types of eruption, effluent vs. explosive, will be discussed and correlated to the geological setting and differences in geochemistry. Examples will be given and discussed for each setting.
Besides the volcanic deposits, e.g. lava, pyroclastic flows, ash and pumice fall outs, the area around a volcano might also be disturbed by landslides due to flank collapse of the volcano, and lahars (mud flows), which are thunderstorms related and induces by the eruption. The general weather might be affected by ash clouds that are introduced in the atmosphere (especially when reaching the meso- and strato-sphere), which can cause worldwide drastic weather changes due to blocking the sunlight up to and sometimes even more than one-year duration.
Several important historic volcanic events and catastrophes will be presented. Based on historical observations, the development of a better understanding and a comprehensive description of the explosive volcanism and the related rock and deposit formation will be discussed.
The aim of this course is to give the student a full overview on all major volcanic activities and processes that can explain the volcanic rock types present on the earth’s surface. Also, some hints will be given to possibly related ore and mineral deposits.