Petrology

The petrology, and Gemology, is the theory of the origin, characteristics and use of the rocks. The term derives from the Greek word πετρος ( petros, Petrus in Latin ), which can be translated as "stone" or "rock". It is a branch of earth sciences and represents the transitional area between two other part regarding: mineralogy, which deals with the constituents of the rocks ( minerals), and geology, which provides the rocks in greater spatial and temporal correlations.

Object of investigation

The petrology is divided into a descriptive part, petrography, and in a genetic part, petrology in the strict sense. The former is concerned among other things with the texture of the rocks, which consists of its structure and texture. The structure describes the components ( grains, crystals in sedimentary rocks and pores) of the rocks. Terms of their size, shape and color as well as the statistical distribution of these properties over the set of all components The texture, however, describes the spatial arrangement of these components in the whole rock in terms of preferred crystallographic orientations. Petrographers deduce from these properties on the suitability of rocks as a material, both in the form of blocks and in broken form. However, petrologists in the narrow sense to use petrographic, structural geology and geochemical evidence to reconstruct the physical and chemical conditions of formation of a rock.

Methods of investigation

Basis of petrological work is field work and geological compass with magnifying glass. Later, the rocks are studied in the laboratory using mineralogical and geochemical methods such as X-ray diffraction and microprobe analysis. Decidedly important petrological method is the polarization microscopy, with the help of the structure of the rocks is investigated. Here are z.T. Additives such as universal turntable used. A method for petrological interpretation of geochemical data is the geothermobarometry that makes statements about pressure and temperature at the time of origination or metamorphosis of a rock. Hypotheses about the origin and evolution ( diagenesis, metamorphism, metasomatism, weathering, hydrothermal overprint ) of a rock be verified by the simulation of geological and mineralogical processes in laboratory experiments. Here, for example, artificial magmas generated and their solidification observed or rocks are brought into contact with aggressive solutions, which are also found in nature. To interpret experimental data gewonnenener, but also as an independent approach to the modeling of igneous, metamorphic and sedimentary processes with the help of computers is used.

Subdisciplines

An outline of the petrology after the object of investigation allows the differentiation of igneous, metamorphic and sedimentary petrology. A differentiation according to the methods of investigation leads to the experimental, analytical and theoretical petrology. Areas that deal with the economic exploitation of rocks, such as as decorative stone, employ, is called Applied Petrology. The transition area to geophysics, in particular deals with the behavior of seismic waves in rocks are called petrophysics.

Study

Petrological course content is " Earth Sciences " conveys the degree program.

Fields of work

Petrologists are for consulting engineers in the site investigation, in mining companies in prospecting, exploration and during operation ( eg as a manager of a quarry ), in builders' merchants in the sale of decorative and building stones, in the public service in geological country offices and at the Federal Institute for Geosciences and raw materials as well as in the scientific field at universities and non-university research institutions operate.