Rock whose texture, mineralogy, or chemical composition has been altered without melting it ... Metamorphism resulting from high temperature and pressure that affects a large region. What is regional metamorphism? Specific zones of temperature and stress outline distinctive metamorphic facies. Thus, it usually results in forming metamorphic rocks that are strongly foliated, such as slates, schists, and gneisses. Regional metamorphism definition at Dictionary.com, a free online dictionary with pronunciation, synonyms and translation. Occurs when very hot water reacts with rock. What are the four agents that drive metamorphism? There are fundamental types of metamorphism: regional metamorphism and phone, or thermal, metamorphism. This type of metamorphism occurs over large areas that were subjected to high degrees of deformation under differential stress. A dense, hard metamorphic rock, typically derived from contact metamorphism. Metamorphism can change the mineralogy, texture, and/or chemical composition of a rock. Crystals in hornfels are so small that specialized study is required to identify them. 1 Textures of Regional Metamorphism FDynamothermal (crystallization under dynamic conditions) FOrogeny- long-term mountain -building sMay comprise several Tectonic Events iMay have several Deformational Phases FMay have an accompanying Metamorphic Cycles with one or more Reaction Events Progressive syntectonic metamorphism of Large crystals of new metamorphic minerals. These topics are followed by the texture examination of thermal metamorphic rocks and minerals and the preferred orientations of these rocks, particularly the dimensional and lattice preferred orientation. Regional metamorphism is a type of metamorphism where rock minerals and texture are changed by heat and pressure over a wide area or region. directional stress, pressure, heat, and chemically active fluids Identified by its dense, fine grained, hard, blocky or splintery texture composed of several silicate minerals. Regional metamorphism. Hydrothermal metamorphism. Porphyroblasts. During metamorphism the mineral content and texture of the protolith are changed due to changes in the physical and chemical environment of the rock. Regional metamorphism occurs because both pressure and temperature increase with depth in … Figure 7.2 The rock cycle. The type of rock that a metamorphic rock used to be, prior to metamorphism, is called the protolith. Although most metamorphism involves temperatures above 150°C, some metamorphism takes place at temperatures lower than those at which the parent rock formed. This kind of metamorphism, called regional metamorphism, creates large metamorphic terranes, regions characterized by distinctive metamorphic rocks and intensity of metamorphism that may vary laterally. Regional metamorphism is associated with the major events of Earth dynamics, and the vast majority of metamorphic rocks are so produced.They are the rocks involved in the cyclic processes of erosion, sedimentation, burial, metamorphism, and mountain building (), events that are all related to major convective processes in Earth’s mantle. Look it up now! Metamorphism can also take place if cold rock near the surface is intruded and heated by a hot igneous body. Most regionally metamorphosed rocks occur in areas that have undergone deformation during an orogenic event resulting in mountain belts that have since been eroded to expose the metamorphic rocks. Metamorphic rocks are categorised by way of texture and mineralogy. Regional metamorphism. Other chapters survey the textures of rocks under dynamic and shock metamorphism. Regional metamorphism is metamorphism that occurs over broad areas of the crust.