The preexisting rocks may be igneous, sedimentary, or other metamorphic rocks. Igneous rocks are formed by the solidification and cooling of magma in volcanic. Metamorphic rock is formed underground through a process that changes a rock s molecular structure due to pressure, heat and chemical reactions. The two major factors that influence the development of metamorphic rocks are heat and pressure. This paper will take a look at the earths rock cycle to examine exactly where the metamorphic rock fits into it. Formation of metamorphic rocks fact sheet oresome resources. This worksheet has 22 short answer questions about metamorphic rock diagrams and graphs. Rock formed by high temperatures and pressures that cause changes in the parent rock while in the solid form. They can be divided into many categories, but they are typically split into. The metamorphic rocks in the study area have been metamorphosed by different. Metamorphic rocks metamorphic rocks definitions definitions metamorphic rock metamorphic rock meta change grk meta change grkmorph form grk morph form grk a rock that has been changed a rock that has been changedfrom its original form parent by from its original form parent by heat, pressure, and fluid. Only a restricted number of new contact metamorphic rock names. Metamorphic rock is formed underground through a process that changes a rocks molecular structure due to pressure, heat and chemical reactions. They are sedimentary or igneous rocks that have undergone changes as a result of extreme pressure and heat.
Metamorphic rock formed when heat andor pressure deep within the planet changes. The name defines their formation whereby meta means change and morph means fo. Place the closed foil packet on the hot plate and place the bacon press on top of the packet. Formation of metamorphic rocks how they are formed igneous, sedimentary and metamorphic rocks can become buried below the earths surface, owing to the movements of the earths plates. These are the rocks that form by the effects of heat, pressure, and shear upon igneous and sedimentary rocks. Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means change in form. Metamorphic rocks are the rocks formed from other rocks. It will also look at how metamorphic rocks are formed and the relationship between metamorphic rocks and igneous rock and sedimentary. A protolith is the original, unmetamorphosed rock from which a given metamorphic rock is formed, e. The chemical components and crystal structures of the minerals making up the rock may change even. Igneous and sedimentary rocks both have the potential to become a metamorphic rock. Metamorphism and metamorphic rocks tulane university.
Mechanical deformation and chemical recrystallization are the two processes that affect rock during metamorphism. A brief introduction to metamorphic rocks including a look at how they form as a result of exposure to intense heat andor pressure. Metamorphic rock such as gneiss, phyllite, schist and slate which have a layered or banded appearance that is produced by exposure to heat and directed pressure. Metamorphic rock metamorphism means to change form. Metamorphic rocks started out as some other type of rock, but have been substantially changed from their original igneous, sedimentary, or earlier metamorphic form. Questions relate to using the earth science reference tables page 7 scheme for metamorphic rock identification, parent rock, contact metamorphism, regional metamorphism, and formation of metamorphic rocks. The characteristic contact metamorphic effects produced around an igneous intrusion, the formation of metamorpic zones and associated rock types that are formed in contact metamorphism environment will be discussed here below. Formation of metamorphic rocks might involve with heat from magma, while it is not so with sedimentary rocks. For example, slate and marble are building materials, garnets are used as gemstones. Some form during mountainbuilding by forces of others from the heat of igneous intrusions in regional metamorphism others from the heat of igneous intrusions in contact metamorphism. Each rock group is further subdivided into subgroups that are defined by the mode of origin of the rocks. Because the dark colored minerals tend to form elongated crystals, rather than sheet like crystals, they still have a preferred orientation with their long directions perpendicular to the maximum differential stress. Remove the foil packet after 5 to 10 seconds time will depend on temperature of hot plate.
Sedimentary rocks are formed from weathered and cemented pieces of other rocks. Foliated metamorphic rocks pr essure squeezes or elongates the crysta ls. These can range from textures similar to the original protolith at low grades of metamorphism, to textures that are purely produced during metamorphism and leave the rock with little resemblance to the original protolith. During metamorphism the protolith undergoes changes in texture of the rock and the mineral make. The same metamorphic facies can contain different mineral assemblages as they are a direct product of different mineral and chemical composition of the original rock, i.
May 2020 petrologyigneoussedimentaryandmetamorphic3rdedition 15 pdf drive search and download pdf files for free. Students can understand that different factors are involved in the formation of metamorphic rocks. The original rock is subjected to heat temperatures greater than 150 to 200 c and pressure 100 megapascals 1,000 bar or more, causing profound physical or chemical change. Metamorphic rock, any rock that results from the alteration of preexisting rocks in response to changing conditions, such as variations in temperature, pressure, and mechanical stress, and the addition or subtraction of chemical components.
Metamorphic rocks rocks ks3 chemistry revision bbc bitesize. A solid, cohesive aggregate of grains of one or more mineral. They have a significant amount of sheet silicate platy minerals and are classified by composition, grain size, and. Metamorphic rocks started out as some other type of rock, but have been substantially changed from their original igneous, sedimentary, or earlier metamorphic form metamorphic rocks form when rocks are subjected to high heat, high pressure, hot mineralrich fluids or, more commonly, some combination of these fa.
As per wikipedia, metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means change in form. Rock formation picture rock formation and identification. In volcanic and seismic activity, the cooling of magma creates igneous rocks, which are buried by further igneous rock formation, soil and vegetation. Suggest possible parents for a given metamorphic rock. Origin, texture, and classification of metamorphic rocks. Metamorphic rock textures there are five basic metamorphic textures with typical rock types basic rock texture metamorphic rocks name of foliation slaty slate and phyllite. There are numerous opportunities for students to practice using the table, both in teams and individually in this lesson, and it also features some information relating to regional metamorphism. Metamorphism involves changes in mineral assemblage and rock texture and occurs in the solid state as a result of changes in temperature and pressure.
When heat and pressure reach the rocks melting point, it melts into magma. Sedimentary and metamorphic rocks notes can be accessed on notes section of website 6. Metamorphism the process through which a rocks structure is changed by heat and pressure. Characteristics of metamorphic rocks science struck.
Have students bring in rocks they have found to show the class. Fold the foil packet with the sedimentary crayon rock shut to seal the packet. These dark colored minerals tend to become segregated into distinct bands through the rock this process is called metamorphic differentiation, giving the rock a gneissic banding. Sedimentary rocks are largely formed by erosion of other types of rocks, most dramatically seen in the form of beach sand, which. Metamorphic rocks teacher guide including lesson plans, student readers, and more information lesson 1 formation of metamorphic rocks lesson 2 metamorphic rock classification chart lesson 3 metamorphic rocks lab lesson 4 the many facies of metamorphic rocks lesson 5 michelangelo and marble designed to be used as an electronic textbook. Primary fabric forms during the formation of the rock tectonic fabric forms as a consequence of tectonic deformation fabric of a rock is the geometric arrangement of component features in the rock, seen on a scale large enough to include many samples of each feature. Difference between metamorphic rocks and sedimentary rocks. One of the oldest types of rocks on our planet, metamorphic rocks are mainly formed due to changes in the parameters of temperature and pressure, which act on the parent material. Metamorphic rocks an overview sciencedirect topics.
A metamorphic rock forms from a parent rock called a protolith. Because protoliths are capable of undergoing vast changes. Metamorphic rocks are formed from igneous and sedimentary rocks. Metamorphic rocks and processes metamorphism comes from the greek words meta change morphe form metamorphic rocks form by solidstate no melting transformation of preexisting rock by processes that take place beneath earths surface.
Metamorphic rocks are an important topic in geology. Such features include folds, nappes, and faults with a wide variety of geometries. The protolith may be a sedimentary, igneous, or existing metamorphic rock. Primary fabric forms during the formation of the rock. Forms when rocks are changed into different kinds of rocks by great heat andor pressure they are heated, squeezed, folded, or chemically changed by contact with hot fluids andor tectonic forces. Geologists are scientists who study the formation, structure, history, and. Sediments produced by weathering and erosion form sedimentary rocks through the process of lithification.
Igneous rocks form when magma, molten rock, rises upward toward the surface and are classified into two types on the basis of texture grain size and composition. Knowledge of metamorphic processes and rocks is valuable, because metamorphic minerals and rocks have economic value. Sedimentary rocks are formed in the earth surface, while metamorphic rocks are formed deep in the earth. Comparing metamorphic, igneous, and sedimentary rocks. The change occurs primarily due to heat, pressure, and the introduction of chemically active fluids. Metamorphism is the change of minerals or geologic texture distinct arrangement of minerals in preexisting rocks, without the protolith melting into liquid magma a solidstate change. Many of the minerals in metamorphic, or changed, rocks are the same silicates, carbonates, etc. Outlines the different factors involved in the formation of metamorphic rocks. Metamorphic meta to change morph form metamorphic rocks are formed from parent rocks preexisting rocks parent rocks can be igneous, sedimentary, or other metamorphic rocks. Igneous rocks, sedimentary rocks and metamorphic rocks. Students are provided with a rock formation picture that has 12 rocks placed in specific locations based on how they are formed sedimentary, metamorphic, igneous. Jul 28, 2011 formation of metamorphic rocks might involve with heat from magma, while it is not so with sedimentary rocks.
Most students have little trouble understanding the formation of igneous and. Gold in igneous, sedimentary and metamorphic rocks by robert s. Metamorphic rocks form when changes in the composition andor texture of a rock. They are subject to forces from the huge weight of soil, sediments and other rocks above them. The analyses for gold made before 1955 tend to be higher than the newer analyses, so separate. In many cases, the correlation of metamorphic isograds and their position in the structure implies a genetic relationship.
Students can understand how metamorphic rocks are formed. The modal content of amphibole is larger than 30% vol. Metamorphic rock metamorphic rock structural features. Alteration and resorption of oceanic crust represent the shortest route through the rock cycle, and there are also strong associations between magma emplacement, subduction and metamorphism. Ii origin, texture, and classification of metamorphic rocks teklewold ayalew encyclopedia of life support systems eolss essentially in the solid state. Metamorphic rocks form at higher temperatures and pressures than sedimentary rocks. Metamorphic processes generally cannot be observed directly.
Pdf the study area is situated at a distance of about 840km to the north of addis. The formation of primary minerals from magma and the importance of silicates lead naturally into igneous processes and landforms. Finally, students may need their earth science reference tables esrt for parts of the lesson a document used widely in the new york state earth science. Metamorphic rock, as its name suggests, is a rock that has changed form. Foliated these have a planar foliation caused by the preferred orientation alignment of minerals and formed under differential stress. Metamorphic rocks form when a rocks mineral composition and texture change are influenced by heat, pressure, fluids, parent rock composition, and duration of metamorphism form through regional, contact, dynamic, shock, hydrothermal, or burial metamorphism can be classified as foliated layered or nonfoliated. The rock mass does not normally disaggregate and lose coherence entirely. Metamorphic rocks are often intimately related to largescale kilometres of tens of kilometres structural features of earth. Students then move the rocks from the formation picture to an identification card based on the descriptions. The name defines their formation whereby meta means change and morph means form. Metamorphic rocks form when rocks are subjected to high heat, high pressure, hot mineralrich fluids or. Read this sciencestruck article to gain extensive information about the main features of these rocks. Depending on conditions, a protolith can transform into any metamorphic rock. Sedimentary rocks form through the deposition of material at the earths surface and within bodies of water.
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