Petrológia

Petrológia, or petrology, is the branch of geology that studies rocks—their origin, composition, texture, structure, and history. It seeks to understand how rocks form and change over geological time and how their mineral content and textures record the conditions of formation, such as temperature, pressure, and chemical environment. Rocks are commonly grouped into igneous, sedimentary, and metamorphic types, and petrology integrates mineralogy, geochemistry, and field observations to interpret rock formation processes. Igneous petrology examines rocks formed by cooling and crystallization of molten material; sedimentary petrology analyzes rocks formed by accumulation, compaction, and cementation of sediments; metamorphic petrology studies rocks transformed by heat, pressure, and fluids without melting.

Subfields include igneous, sedimentary, and metamorphic petrology, often addressed together with petrography, geochemistry, and isotopic studies to reconstruct histories of rocks and crustal evolution.

Methods include petrographic microscopy on thin sections, X-ray diffraction for mineralogy, geochemical assays for major and trace elements, mass spectrometry for isotopes, electron microscopy, and in-situ dating techniques such as U-Pb or Ar-Ar. Field mapping and rock sampling provide context for laboratory analyses.

Applications of petrology encompass natural resource exploration and evaluation (ores, hydrocarbons, building materials), understanding tectonics and crustal evolution, and supporting engineering geology and environmental assessments.

History: petrology emerged as a distinct scientific discipline in the 18th and 19th centuries with advances in mineralogy and crystallography, expanding through modern geochemistry and planetary geology.