Igneous rocks form due to one of the most important natural processes, i.e. melt generation in the upper mantle or in the lower crust followed by magma uprise, stalling, crystallization, mixing of other magmas, contamination by wall rocks and finally either solidification at the depth or eruption onto the surface. This natural processes has been taking place since the formation of our planet. Magmatism is close related to plate tectonic processes and a general consensus has been developed that certain rock types prevail at particular tectonic setting. Data are growing significantly from igneous rocks from all over the world and this huge information could help scientists to interpret the petrological and geochemical features of igneous formations. Nevertheless, there are still a lot of open questions waiting to be resolved, but this is the what helps geoscientists to go on, go into the details and attempt to refine our knowledge how magma forms, what happens between melt generation and the formation of the igneous rocks and how we can use this knowledge in our society. Volcanic activity provides advantage and disadvantage for society, volcanoes could be potentially dangerous and therefore scientists are working hard to obtain information from volcanic rocks to know more about the mechanism of volcanic eruption, to know more about the pre-eruption processes in the plumbing system beneath volcanoes. All these information is hidden in the volcanic rocks as well as in the intrusive rocks. The volcano petrology provides a challenging perspective even in eruption forecasting activity. Furthermore, igneous rocks play an important role in having more information about the geodynamic evolution of a given area as well as ore resources prospecting.
The Carpathian-Pannonian region located in eastern-central Europe provides an excellent opportunity to investigate a wide spectrum of igneous rocks from peridotites to granites and from nephelinites and leucitites to phonolites and rhyolites. It is indeed a natural laboratory for studying igneous rocks! In this e-book, our aim is to show the main characteristics of igneous rocks using examples from this region. Characteristic microscopic pictures of certain igneous rocks from different localities could give a general impression about the occurrences of such rocks. We know that this summary is far from being complete and we plan to extend this to other areas and other localities. Nevertheless it is the first comprehensive summary on the igneous rocks of this region that could help students to get a general picture about igneous rocks and their localities in the Carpathian-Pannonian region.