Recognize the different types of metamorphism, the processes that cause them, and the environments in which they occur. Metamorphic they are formed through the change metamorphosis of igneous and sedimentary rocks. Origin, texture, and classification of metamorphic rocks. Involves recrystallization in the solid state, often with little change in overall chemical composition. Rock metamorphism is a geological process that changes the mineralogical and chemical composition, as well as the structure of rocks. A new foliation begins to develop along the axial planes of the folds. O such that c 9 three components is the maximum number that we can easily deal with in two dimensions what is the right choice of components. Microtextures of igneous and metamorphic rocks pdf free. The rocks provide clues to their transformation into a metamorphic rocks. Slate is formed from low grade regional metamorphism of fine grained sedimentary mudrocks. This lab is a simple identification lab which can be used with any 6 or less metamorphic rocks listed on the esrt that teachers have in stock. Metamorphic rocks types and properties of metamorphic rocks.
Follows this introductory reference table lab attached below. Petrogenesis of metamorphic rocks presents a large number of diagrams showing the stability relations among minerals and groups of minerals found in metamorphic rocks. Many precious materials, such as marble and many types of gemstones, including diamonds, are formed by the metamorphic process. Metamorphic rocks form when rocks are subjected to high heat, high pressure, hot mineralrich. Metamorphic zones, defined on the basis of mineral reactions, very effectively display the evolution of metamorphic rocks. Metamorphism is typically associated with elevated temperature and pressure, thus it affects rocks within the earths crust and mantle. The presence of these parallel planes of weakness makes this rock distinct from original. Metamorphic rocks revised on 1082012 page 2 of 9 igneous rocks form from magma, which is not a rock since it is a fluid and sedimentary rocks lithify from loose sediment or precipitate from a solution. Metamorphic rocks are classified by their protolith, which is the parent rock or the original, unmetamorphosed rock, and by texture. This is a texture that has a tendency to break into thin sheets or layers due to the alignment of platy minerals from the pressure involved with increasing regional metamorphism.
Hornfels is a finegrained metamorphic rock formed by the action of heat on clay rocks, known as contact metamorphism. All regional metamorphic rocks that display rock cleavage are said to have a foliated texture. Field description of metamorphic rocks the basic procedural aspects of writing a description for metamorphic rocks or rock units are identical to those for sedimentary rocks and rock units. Hornfels are heated when near heat source such as a sill, dike, or magma chamber. Nelson metamorphism and metamorphic rocks definition of metamorphism the word metamorphism comes from the greek. Driving forces are changes in temperature, pressure, and pore fluids.
The name refers to the process of metamorphism, which means to undergo notable alteration to the original form. By this definition schist is a broad term, and slates and phyllites are also types of schists. Metamorphic rocks are rocks that have changed from igneous rocks or metamorphic rocks. It is a homogeneous fine grained rock which can be split into thin or thick sheets with relatively smooth surfaces. Metamorphic rocks started out as some other type of rock, but have been substantially changed from their original igneous, sedimentary, or earlier metamorphic form. Regional associated with mountain buildings also known as dynamothermal produces both foliated and nonfoliated metamorphic rocks. Metamorphism occurs at higher pressure and temperature than weathering and diagenetic processes. Metamorphic rocks form when rocks are subjected to high heat, high pressure, hot mineralrich fluids or, more commonly, some combination of these factors. They occur when sedimentary and igneous rocks become changed, or metamorphosed, by conditions underground.
Metamorphic rocks and rock cycle flashcards quizlet. Chemical, mineralogical and structural adjustments of solid rocks to physical and chemical. Metamorphic rocks and rock cycle study guide by gmk6 includes 7 questions covering vocabulary, terms and more. Metamorphic rocks are one of the three types of rocks in the rock cycle. Pdf the field description of metamorphic rocks download. A metamorphic rock is a rock that has been changed by heat andor pressure without completely melting. Metamorphic rocks are formed from parent rocks parent rock the original rock material that forms metamorphic rock example.
The preexisting rocks may be igneous, sedimentary, or other metamorphic rocks. Hand specimen descriptions of metamorphic rocks hand specimen descriptions for metamorphic rocks are like those for igneous rocks. Find materials for this course in the pages linked along the left. Chemical, mineralogical and structural adjustments of solid rocks to physical and chemical changes at depths below the region of sedimentation. Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means change in form. Igneous rocks form when rocks are heated to the melting point which forms magma. The objective is to tell someone looking at it everything they need to know to recognize it in the field. Rock cycle means the process by which rocks are formed, degraded and reformed by the internal geological processes like plutonism, volcanism, uplift etc andor by external geological. Textures of metamorphic rocks excess energy present in deformed crystals elastic, twins, surface free energy growth of new grains leads to decreasing free energy release elastic energy, reduce surface to volume ratio increase grains size, exception occurs in zones of intense shearing where a number of nuclei are formed. Metamorphism encompasses all solidstate changes in the fabric and composition of a rock body occurring well beneath the surface of the earth, but without the.
When sedimentary rocks or igneous rocks go through the physical process such as pressure exposure, heat changes, and tectonic plate movement at. A rock or a rock complex may bear the effects of more than one metamorphic event e. Mechanical deformation and chemical recrystallization are the two processes that affect rock during metamorphism. Thus, the importance of reactions in metamor phic rocks is emphasized. The four main agents that metamorphose rocks are heat, pressure, fluids, and strain. Monometamorphism is a metamorphism resulting from one metamorphic.
Metamorphic rock, any of a class of rocks that result from the alteration of preexisting rocks in response to changing environmental conditions, such as variations in temperature, pressure, and mechanical stress, and the addition or subtraction of chemical components. Rocks are formed on earth as igneous, sedimentary, or metamorphic rocks. Like water cycle, there exist rock cycle geological cycle in geology. Metamorphic rocks most common natural rocks contain the major elements. Metamorphic rocks are formed when rock changes over a period of time due to a lot of physical changes like pressure, heat and different chemical activity.
In fine grained metamorphic rocks small scale folds, called kink bands, often develop in the rock as the result of application of compressional stress. It has a nonfoliated metamorphic rock that has no specific composition. Describe how metamorphic rocks are produced by the action of heat, pressure, and fluids on preexisting parent rocks over the course of time. Metamorphic rocks can be formed from any rock type. Metamorphic rocks form by solidstate no melting transformation of preexisting rock by processes that take place beneath earths surface. Metamorphic rocks are best identified when looking at the rock as you see them in nature. Metamorphism encompasses all solidstate changes in the fabric and composition of a rock body occurring well beneath the surface of the earth, but without the production of a melted stage i. Metamorphic rocks form gradually from existing rocks in solid state, so they remain rocks throughout the process. Metamorphic rocks in nature shale to slate metamorphism deformation of sedimentary rocks metamorphic rocks record how temperature and pressure affected an area when it was forming. Associated with mountain belts affects very large areas. Metamorphic rocks formed from parent sedimentary rocks are called parametamorphite e. Petrogenesis of metamorphic rocks kurt bucher springer. These agents can act and interact in an almost infinite variety of ways.
Summarize how cleavage and foliation are expressed in metamorphic rocks. Ii origin, texture, and classification of metamorphic rocks teklewold ayalew encyclopedia of life support systems eolss some metamorphic rocks, particularly those buried to depths of several kilometers, contain numerous veins rich in quartz and feldspar. In common usage, schists are restricted to those metamorphic rocks in which the foliated minerals are coarse enough to see easily in hand specimen. Include the following terms, heat pressure, magma, 2. Experimental calibration of mineral reactions makes it possible to distinguish reactions which are of petrogenetic sig nificance from those which are not. Metamorphic core complexes 173 continental and oceanic core complexes a core complex is a domal or arched geologic structure composed of ductilely deformed rocks and associated intrusions underlying a ductiletobrittle highstrain zone that experienced tens of kilometers of normalsense displacement in response to lithospheric. The next three deal with the criteria for establishing the order of crystallization in igneous and metamorphic rocks, a topic which is rather underplayed in other texts on mineral textures. Objectives university of nairobi personal websites. What are metamorphic rocks and how are they formed.
The protolith may be a sedimentary, igneous, or existing metamorphic rock. Quizlet flashcards, activities and games help you improve your grades. Pdf petrogenesis of metamorphic rocks, 8th edition. The outcome of metamorphism will cause significant enough physical and chemical changes to the original rock type, or protolith. Metamorphic rocks are the third great class of rocks.
Because of how they are formed, metamorphic rocks constitute a great deal of the bedrock in earths crust. Difference between metamorphic rocks and sedimentary rocks. Metamorphism involves changes in mineral assemblage and rock texture and occurs in the solid state as a result of changes in temperature and pressure. Chapters 6 and 7 give examples of microtextures for igneous and metamorphic rocks, respectively. Sedimentary rocks are formed from the cementing together of sediments, or from the compaction squeezing together of sediments, or from the recrystallization of new mineral grains which are larger than the. Similarly, those resulting from original igneous rocks are known as orthometamorphite say, formed from granite and granodiorite. Metamorphic rocks are the third major type of rock, the other two being igneous and sedimentary. Descriptions should be reasonably comprehensive but clear. The diagrams help to determine the pressure and temperature conditions under which a given set of metamorphic rocks. Pressure regional metamorphism regional metamorphism regional metamorphism usually occurs deep underground.
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