Regional thermal metamorphism and deformation of the. Metamorphism of pelitic rocks during subduction produces chlorite sudoite, carpholite and chloritoid at relatively low pressure, and mgrich. Chart and diagram slides for powerpoint beautifully designed chart and diagram s for powerpoint with visually stunning graphics and animation effects. A process of change 1 metamorphic rock forms from a preexisting rock or protolith. Pelitic rocks are slates or phyllites and typically contain chlorite, muscovite, quartz and albite.
Prograde polyphase regional metamorphism of pelitic rocks, nw of. Metamorphism in pelitic hornfels rocks is also discussed and migmatitic textures are illustrated. Metamorphic petrology 3 metamorphism of pelitic rocks minerals and isograds. Regional metamorphism of pelitic rocks pelites are derived from clay rich sediments and are of significant importance because they develop wide range of distinctive. If the temperature of metamorphism is high enough for partial melting of the rock to occur, the changes would still be called metamorphism until the melt is separated from its. The fremont peak pendant is the largest of many small exposures of sur series metasedimentary rocks in the northern gabilan range which lies along the eastern edge of the central salinian block, california coast ranges. The intensity of contact metamorphism decreases from the innermost. Barrovian metamorphism is widely found across time and space on all parts of the earth, and produces the most common metamorphic rocks.
In these rocks the transitions from nonmetamorphic to very lowgrade and from very lowgrade to lowgrade metamorphic domains take place through the diagenetic zone, the anchizone and the epizone, each zone being characterized by specific values of the illite kubler index ki arkai et al. Rock can be heated by burial, exposure to igneous intrusions, or collision each of these can be associated with different pressures so metamorphism can rarely be due only to temperature the term stress implies direction, and is a more useful term than pressure, especially since metamorphic rocks record differential stress. Prograde barrovian type of metamorphism of pelitic rocks around. Progressive metamorphism of pelitic and quartzofeldspathic rocks in. Greenschist facies to amphibolite facies conditions are indicated by the formation of the index minerals chloritoid, garnet, staurolite and kyanite in. Rock metamorphism is primarily induced by largescale tectonic changes, processes that occur over very long time intervals, commonly 10 5 to 10 6. He observed that as a pelitic rock undergoes higher pressures and temperatures, its mineral assemblage changes from predominantly chlorite to biotite to. Metamorphic rocks can be formed from igneous, sedimentary, or previously metamorphosed rocks by recrystallization in the solid state. After chlorite breaks down the kyanite forms in many metapelites. Petrogenesis of metamorphic rocks kurt bucher springer. The zone where contact metamorphism occurs is called the contact aureole, while the products of such metamorphism are called contact rocks. Barrow 1893 mapped metamorphic zones in pelitic rocks based on mineral assemblages he observed in a small part the area. Regional metamorphism of pelitic rocks pelitic rocks are fine grained mudstones, siltstones and shales that contain a high percentage of clays, with lesser quartz and variable amounts of calcite. Very lowgrade metamorphic evolution of pelitic rocks under high.
During regional metamorphism of pelitic rocks e,g, shale, a common sedimentary rock, rich in clay minerals alrich, typical metamorphic. Buchan facies series metamorphism is in northeastern scotland see map above in the dalradian series. Result of low temperature hydrothermal alteration andor metamorphism in the zeolite facies. Metamorphism, fluid flow and partial melting in pelitic rocks. Metamorphism of pelitic rocks during subduction produces chlorite sudoite, carpholite and chloritoid at relatively low pressure, and mgrich garnet, talc, kyanite, andor sirich white mica at. Although begin as humble mud, metapelites represent a distinguished family of metamorphic rocks, because. Progressive metamorphism of pelitic rocks from greenschist to upper amphibolite facies in the area around kandra, saraikelakharsawan district, jharkhand. Regional metamorphism of pelitic rocks pelites are derived from clay rich sediments and are of significant importance because they develop wide range of distinctive minerals very fine grained mature clastic sediments derived from continental crust. Structure and petrology of pelitic schist in the fremont. Winter, chapter 28 metapelite mineralogy fine alkrich phyllosilicates, such as clays montmorillonite, kaolinite, or smectite, fine white micas sericite, paragonite, or phengite and chlorite the phyllosilicates may compose more than 50% of the original sediment fine quartz constitutes another 1030%. It occurs in intense tectonic conditions associated with volcanic arcs, and major mountain building. In the late 1800s and early 1900s, george barrow discovered the classic barroviantype metamorphic sequence in the southeastern scottish highlands.
In the study of very low and lowgrade metamorphic rocks, maturation of organic matter and reaction progress, and. Field, petrologic and geochemical data were used to characterize fluid infiltration and partial melting during metamorphism of pelitic rocks in the contact aureole of the onawa pluton, central maine, usa. A fluidinclusion study of metamorphosed pelitic and. A thorough presentation on characteristics and description of all main types of metamorphic rocks. Differential stress aligns the micas, so a pronouncedfoliationis developed. Metamorphism of greater and lesser himalayan rocks.
These changes produce new minerals,new textures,and new structures within the rock body. 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. Sep 23, 2016 when sedimentary rocks are buried to depths of several hundred meters, temperatures greater than 300oc may develop in the absence of differential stress. Petrogenesis of metamorphic rocks presents a large number of diagrams showing the stability relations among minerals and groups of minerals found in metamorphic rocks. Metamorphic rocks presentation free download as powerpoint presentation. The thickness of the aureole ranges from the millimetre to the kilometrescale. Effected by lower paleozoic caledonian orogeny barrow recognized metamorphism was progressive. Structure and petrology of pelitic schist in the fremont peak. The diagrams help to determine the pressure and temperature conditions under which a given set of metamorphic rocks may have formed. Much information on metamorphism of these rock types has already been given when describing individual units, so this section is focussed on providing a synthesis. Progressive metamorphism of pelitic rocks from protolith to.
Metamorphism conference paper pdf available progressive metamorphism of pelitic rocks from greenschist to upper amphibolite facies in the area around kandra. Metamorphism of basic and pelitic rocks at sulitjelma. Changes occur in the solid state because melting doesn t occur. At a higher grade the chlbt tieline flips to the tlccld tieline c. Contact metamorphism of pelitic rocks in the skiddaw aureole, uk the zones determined on a textural basis prefer to use the sequential appearance of minerals and isograds to define zones but lowp isograds converge in pt skiddaw sequence of mineral development with grade is difficult to determine accurately. One or two of the minerals listed for mafic or calcareous or pelitic rocks in the appropriate facies may also be present. Download free pdf progressive metamorphism of pelitic rocks from protolith to granulite facies, dutchess county, new york, usa. Metamorphic petrology 5 metamorphism of mafic rocks. The chemical components and crystal structures of the minerals making up the rock may change even. Diagnostic minerals in metamorphosed pelitic rocks barrovian metamorphism regional orogenic metamorphism in the scottish highlands chlorite zone slates or phyllites muscovite important chlorite biotite highergrade part of facies pyrophyllite chloritoid albite lowergrade part of facies.
Pelites are derived from clay rich sediments and are of. Metamorphism of greater and lesser himalayan rocks exposed in. Chemical, mineralogical and structural adjustments of. Metamorphism of pelitic rocks metapelites springerlink. This resource is part of the teaching petrology collection.
In geology this refers to the changes in mineral assemblage and texture that result from subjecting a rock to pressures and temperatures different from those under which the rock originally formed. Many distinct metamorphic minerals are found in meta pelitic rocks e. This implies a large and pervasive hro influx during the initial stages of metamorphism. The progressive nature of metamorphism a rock at a high metamorphic grade probably progressed through a sequence of mineral assemblages rather than hopping directly from an unmetamorphosed rock to the metamorphic rock. Pdf metamorphism of pelitic alrich rocks researchgate. The precursors to these hightemperature metamorphic. Alpine metamorphism of pelitic schists in the nufenen pass. The term was earlier used by geologists to describe a clayrich, finegrained clastic sediment or sedimentary rock, i. Metamorphism conference paper pdf available progressive metamorphism of pelitic rocks from greenschist to upper amphibolite facies in the area around kandra, saraikelakharsawan district, jharkhand.
Prograde polyphase regional metamorphism of pelitic rocks, nw. Hornfelses are tough, and tend to splinter when broken. Lecture notes petrology earth, atmospheric, and planetary. Lecture eight metamorphism of pelitic rocks metapelites. Contact metamorphism in pelitic rocks on the island of kos greece. Progressive metamorphism of pelitic rocks from protolith to granulite. Pdf progressive metamorphism of pelitic rocks from. Orthopyroxene occurs in pelitic and quartzofeldspathic rocks only at the very highest grades of contact and regional metamorphism, grades that may not be reached prior to melting in many instances. Oct 25, 2000 barrovian metamorphism is the most commonly encountered. Metamorphism at high temperatures and low to medium pressures is widespread in many orogenic belts. The change occurs primarily due to heat, pressure, and the introduction of chemically active fluids.
Very lowgrade metamorphic evolution of pelitic rocks under. A more precise location is presented on a geologic map by guidotti 1963. Pelitic rocks read chapter 3 of an introduction to metamorphic petrology by bruce yardley or chapter 28 of igneous and metamorphic petrology by john winter. Prograde polyphase regional metamorphism of pelitic rocks, nw of jamshedpur, eastern india. Sep 25, 2017 the word metamorphism comes from the greek. It represents a common type of regional pelitic orogenic metamorphism.
Following a common pattern, the intrusions are shallow, and the. Pelitic rocks are slates or phyllites and typically. Symmes gh, ferry jm 1992 the effect of whole rock mno content on the stability of garnet in pelitic schists during metamorphism. In many common rock types, such as marine pelites and carbonates, no diagnostic minerals or mineral. Interaction between metamorphism and deformation part 12. Contact metamorphism of pelitic rocks in the skiddaw aureole, uk ordovician skiddaw slates in the english lake district are intruded by several granite and granodiorite bodies. Metamorphism, fluid flow and partial melting in pelitic. Progressive metamorphism of pelitic rocks from protolith to granulite facies, dutchess county, new york, usa. Metamorphic zones in pelitic rocks, and locations of diagnostic mineral assemblages. Pelitic rocks are fine grained mudstones, siltstones and shales that contain a high percentage of clays, with lesser quartz and variable amounts of calcite. The diagrams help to determine the pressure and temperature conditions under which a given set of metamorphic rocks may have. Apr 18, 2012 buchan facies series metamorphism is in northeastern scotland see map above in the dalradian series.
The presentation uses akf diagrams to describe barrovian zones of metamorphism in metapelites. Metamorphic rocks metamorphic rocks are classified on the basis of texture and composition either mineralogical or chemical unlike igneous rocks, which have been plagued by a proliferation of local and specific names, metamorphic rock names are surprisingly simple and flexible may choose some prefixtype modifiers to attach. If the temperature of metamorphism is high enough for partial melting of the rock to occur, the. Mineral associations and localities of samples of pelitic and semipelitic rocks. Prograde polyphase regional metamorphism of pelitic rocks. Other zeolite minerals are analcime, clinoptilolite, heulandite, natrolite, phillipsite, and stilbite. Progressive metamorphism of pelitic rocks from protolith. This powerpoint presentation includes 30 slides discussing metamorphism in pelitic rocks. Metamorphism of basic and pelitic rocks at sulitjelma, norway. The protoliths for pelitic rocks are shales aluminous rocks, not sandstones quartzofeldspathic rocks here are the stability fields of common pelitic minerals. Kisch, chapter 5 mineralogy and petrology of burial diagenesis burial metamorphism and incipient metamorphism in clastic rocks, diagenesis in sediments and sedimentary rocks, 10. Thickness 1015 km thick some structural thickening.
Regional thermal metamorphism and deformation of the sitka. Preface this new edition of petrogenesis of metamorphic rocks has several completely revised chapters and all chapters have updated references and redrawn. Maine, have been regionally metamorphosed to the biotite, garnet. 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 petrology 4 pelites the akfm system continuous and discontinuous reactions. Lower paleozoic pelitic rocks in the errol quadrangle, northern new hampshire and. Contact metamorphism of pelitic rocks in the skiddaw aureole, uk the zones determined on a textural basis prefer to use the sequential appearance of minerals and isograds to define zones but lowp isograds converge in pt skiddaw sequence of mineral development with grade is. Here the pelitic rocks in the mapped zones contain the following mineral assemblages.
Greenschist facies to amphibolite facies conditions are indicated by the formation of the index minerals chloritoid, garnet, staurolite and kyanite in pelitic rocks. Their high al content leads to a highpercentage of micasin the resulting metamorphic rock. New minerals grow, but the rock does not appear to be metamorphosed. Petrologic characterization of pelitic schists in the western. Early eastwest trending, isoclinal folding accompanied by sillimanite. Abstract a complete barrovian sequence ranging from unmetamorphosed shales to sillimanitekfeldspar zone metapelitic gneisses crops out in a region. Burial metamorphism overlaps, to some extent, with diagenesis, and grades into.
Contact metamorphism of pelitic, psammitic and calcareous. Metamorphism of greater and lesser himalayan rocks exposed in the modi khola valley, central nepal aaron j. Their high al content leads to a high percentage of micas in the resulting metamorphic rock. Fingerprint dive into the research topics of progressive metamorphism of pelitic rocks from protolith to granulite facies, dutchess county, new york, usa. Constraints on the timing of fluid infiltration during regional metamorphism. Very lowgrade metamorphic evolution of pelitic rocks.
Regional metamorphism of pelitic rocks patna university. This question hasnt been solved yet ask an expert ask an expert ask an expert done loading. Rock metamorphism an overview sciencedirect topics. The driving forces for metamorphism are changes in temperature,pressure,and composition of pore fluids. Talc forms between biotite and chlorite along the mgrich side of the diagram. Jun 01, 1986 conclusions the pelitic and basic rocks discussed in this paper show mineralogical changes characteristic of prograde regional metamorphism under greenschist facies and amphibolite facies conditions, the major mineralogi cal change in pelitic rocks is the formation of garnet and biotite at the expense of muscovite, chlorite and carbonate. Introduction previous geologic studies on baranof island loney and others, 1975, p. Overview of metamorphism and tectonics uc santa barbara. During metamorphism, new minerals grow at the expense of old minerals, andor the shape, size, and arrangement of grains in the rock may change. Our new crystalgraphics chart and diagram slides for powerpoint is a collection of over impressively designed datadriven chart and editable diagram s guaranteed to impress any audience. Lecture notes metamorphism introduction metamorphism is a change of form that includes the growth of new minerals, typically in response to a rise in temperature and normally without the involvement of a magma. The pelitic rocks in the bryant pond area have been metamorphosed to the sillimanite and sillimanitepotash feldspar grades of metamorphism and an isograd fig.
1402 6 1184 35 996 1040 42 120 921 639 11 182 891 1890 1839 1653 967 499 1418 132 373 1143 228 770 68 1175 1306 1622 1250 723 1165 20 1337