batuan METAMORFTemu ke duabelasDefinitionsMetamorphic Rock-"Meta"= Change (Grk)-"Morph"= form(Grk)Metamorphic Rock-"Meta"= Change (Grk)-"Morph"= form(Grk)-a rock thathas been changedfrom its original form( parent ) byheat ,pressure, andfuid activityintoa new rock ( daughter)-a rock thathas been changedfrom its original form( parent ) byheat ,pressure, andfuid activityintoa new rock ( daughter )Metamorphic RocksMetamorphic RocksTypes of MetamorphismTypes of MetamorphismContact -caused by igneous activityDynamic-associated with faults ! earth"uake #onesRegional-caused by tremendous pressuresassociated with tectonic plate activityContact -caused by igneous activityDynamic-associated with faults ! earth"uake #onesRegional-caused by tremendous pressuresassociated with tectonic plate activityMetamorphic TexturesMetamorphic TexturesFoliated-$olios = page or leaf%like-rock has distinct banding or layering> often not smooth like in sedimentary rocks-formed under directed pressureNon-foliated-no distinct layering character-often a massive crystalline te&ture-formed under uniform pressuresFoliated-$olios = page or leaf%like-rock has distinct banding or layering-formed under directed pressureNon-foliated-no distinct layering character-often a massive crystalline te&ture-formed under uniform pressuresFoliated TextureFoliated TextureFoliated TexturesFoliated TexturesSlatey-looks like blackboard>dull surface-smooth, thin layering-breaks into fat slabs> referred to as slatey cleavage-no mineral grains visiblePhyllitic-looks like wa&ed surface>has a "sheen" to it-may have little "waves" onsurface>referred to ascrenulations-some small grains visible-looks like blackboard>-smooth, thin layering-breaks into fat slabs>-no mineral grains visible-looks like wa&ed surface>-may have little "waves" onsurface>-some small grains visibleSchistose--visible grains> garnets, staurolites-may have shiny> due to mica mineralsneissic-larger grains-may look like igneous rock-may have crude banding>intensely distorted-di'erent minerals thanschistose -distinct bands of minerals-visible mineral grains>-may have shinyappearance >-larger grains-may look like igneous rock-may have crude banding>-di'erent minerals thanschistose Foliated MM RocksFoliated MM RocksslateslateschistschistgneissgneissphyllitephylliteMM Rocks that could form as a shale !sedimentary" parent rock isMM Rocks that could form as a shale !sedimentary" parent rock isexposed to increasing directed pressure and temperature Mar#le$Mar#le$--metamorphosedmetamorphosedlimestonelimestone %uart&ite$%uart&ite$--metamorphosedmetamorphosed"uart# sandstone"uart# sandstone %uart&ite$%uart&ite$--metamorphosedmetamorphosed"uart# sandstone"uart# sandstoneNon-foliated RocksNon-foliated Rocks Non-foliated RocksNon-foliated RocksIdentifying Metamorphic RocksIdentifying Metamorphic RocksIdentifying Metamorphic RocksIdentifying Metamorphic RocksIdentifying Metamorphic RocksIdentifying Metamorphic RocksClassi(cation of Metamorphic )ocks Metamorphic processes cause many changes in existing rocks, including increased density, formation of larger crystals, foliation, and formation of new minerals.Metamorphic rocks are generally classified as;1)Foliated Rocks2)on!Foliated RocksClassi(cation of Metamorphic )ocksFoliated Rocks Include:1)SlateFine!grained foliated rock. "ut foliation is not #isi"le.$as excellent rock clea#age and splits easily. %his property makes slate useful for tiles and "illiard ta"les.Forms from low!grade metamorphism of shale.ShaleSlateClassi(cation of Metamorphic )ocksFoliated Rocks Include:2)PhylliteFine!grained foliated rock,with #isi"le foliation.ew minerals are often formed. For example,&arnet.Forms from intermediate!grade metamorphism of slate.SlatePhylliteClassi(cation of Metamorphic )ocksFoliated Rocks Include:3)Schist'oarse!grained foliated rock, with distinct foliation.ew minerals are often formed. For example,&arnet.Forms from high!grade metamorphism of phyllite.Schist%hese rocks are (platy)and can "e split intoflakes or sla"s.Classi(cation of Metamorphic )ocksFoliated Rocks Include:4)Gneiss'oarse!grained foliated rock, with distinct foliation.Most common mineralsare *uart+ and feldspar.Forms from high!grade metamorphism of schist.Gneiss%hese rocks display elongated and granular minerals which gi#e therock a dark and light "anded appearance.Classi(cation of Metamorphic )ocksNonFoliated Rocks Include:!)"a#bleMar"le is used for statues and gra#estones.,uring recrystalli+ation of limestone, "edding, fossils, and other sedimentary features are destroyed.'oarse crystalline network of calcite grains that form as a result of recrystalli+ation.%he parent rock of mar"le is -imestone."a#ble$imestoneClassi(cation of Metamorphic )ocksNonFoliated Rocks Include:%)&ua#t'ite.uart+ite is a #ery hard rock.Moderate to high!grade metamorphism fuses the sand grains./ometimes outlines of the original grains may "e seen, a feature called ghosting.Forms when silica sand grains and silica cementrecrystalli+e forming a coarse grained network of silica. %he parent rock of *uart+ite is *uart+ sandstone.&ua#t'ite&ua#t' SandstoneFasies "etamo#(isme$*C+,- .)*/,$*C+,-SelesaiSelamat bela)a# menu)u *+SM0%1M2R3$4/MFa"ric of Metamorphic RocksFa"ric of Metamorphic Rocks'rystallo"lastic !"lastic 5 results from metamorphismidio"lastichypidio"lasticxeno"lastic#s. oncrystallo"lasticrelict"lasto! 5 relict'rystallo"lastic !"lastic 5 results from metamorphismidio"lastichypidio"lasticxeno"lastic#s. oncrystallo"lasticrelict"lasto! 5 relict%extures6%extures6M0%1M2R3$4/MFa"ric of Metamorphic RocksFa"ric of Metamorphic Rocks'rystallo"lastic /eries'rystallo"lastic /eriesRutile, sphene, magnetite%ourmaline, kyanite, staurolite, garnet, andalusite0pidote, +oisite, forsterite3yroxenes, amphi"oles, wollastoniteMicas, chlorite, talc, stilpnomelane,olomite, calcite/capolite, cordierite, feldspars*uart+Rutile, sphene, magnetite%ourmaline, kyanite, staurolite, garnet, andalusite0pidote, +oisite, forsterite3yroxenes, amphi"oles, wollastoniteMicas, chlorite, talc, stilpnomelane,olomite, calcite/capolite, cordierite, feldspars*uart+4dio"lastic4dio"lastic7eno"lastic7eno"lastic%extures6M0%1M2R3$4/MFa"ric of Metamorphic RocksFa"ric of Metamorphic Rocks/hape6grano"lasticnemato"lasticlepido"lastic/hape6grano"lasticnemato"lasticlepido"lastic%extures6M0%1M2R3$4/MFa"ric of Metamorphic Rocks6Fa"ric of Metamorphic Rocks62ther textures6porphyro"lasticpoikilo"lasticaugen"lastoporphyritic"lastoophitic2ther textures6porphyro"lasticpoikilo"lasticaugen"lastoporphyritic"lastoophitic%extures6M0%1M2R3$4/MFa"ric of Metamorphic Rocks6Fa"ric of Metamorphic Rocks6/tructure6-ineation ! any linear fa"ricelementsFoliation ! any planar fa"ricelementMetamorphic rocks with predominantly nematoblastic minerals are more correctly termed lineated, "ut are usually lumped in with the foliated rocks.M0%1M2R3$4/MFa"ric of Metamorphic Rocks6Fa"ric of Metamorphic Rocks6/tructures 8 %ypes of Foliation6/laty clea#age6%raditionally6 the property of a rock to splitalong a regular set of su"!parallel, closely! spaced planes1 more general concept adopted "y somegeologists is to consider clea#age to "eany type of foliation in which the aligned platy phyllosilicates are too fine grained tosee indi#idually with the unaided eyeM0%1M2R3$4/MFa"ric of Metamorphic Rocks6Fa"ric of Metamorphic Rocks6/tructures 8 %ypes of Foliation6/chistosity61 preferred orientation of ine*uant mineral grains or grain aggregates produced "y metamorphic processes1ligned minerals are coarse grained enough to see with the unaided eye%he orientation is generally planar, "ut linear orientations are not excluded M0%1M2R3$4/MFa"ric of Metamorphic Rocks6Fa"ric of Metamorphic Rocks6/tructure6&neissic 9gneissose)60ither a poorly!de#eloped schistosity or segregated into layers "y metamorphic processes&neissose rocks are generally coarse grained M0%1M2R3$4/Maming Metamorphic Rocks6aming Metamorphic Rocks6Metamorphic rocks may "e named "ased on6 protolithology structure 9type of foliation) structure and:or composition 9nonfoliated; comp.) chemistryM0%1M2R3$4/Maming Metamorphic Rocks6aming Metamorphic Rocks6Metamorphic rocks may "e named "ased on6 protolithologye.g.6meta!*uart+ite, meta! "asalt, etc.4n the case of non!crystallo"lastic rx, usuallythe most appropriate method, otherwisenot as descripti#e as other methodsM0%1M2R3$4/Maming Metamorphic Rocks6aming Metamorphic Rocks6Metamorphic rocks may "e named "ased on6 protolithology structure 9type of foliation) structure and:or composition 9nonfoliated; comp.) chemistryM0%1M2R3$4/Maming Metamorphic Rocks6aming Metamorphic Rocks6Metamorphic rocks may "e named "ased on6/tructure 9type of foliation)%he classical 9and our) way of naming the foliated9or lineated) metamorphic rocks slate phyllite schist gneissM0%1M2R3$4/Maming Metamorphic Rocks6aming Metamorphic Rocks6/late6 com,act- .e#y (ine/#ained- metamo#,hic #ock 0ith a 0ellde.elo,ed clea.a/e1 F#eshly clea.ed su#(aces a#e dull a #ock 0ith a schistosity in 0hich .e#y (ine ,hyllosilicates 2se#icite3,hen/ite and3o# chlo#ite)- althou/h #a#ely coa#se enou/h to see unaided- im,a#t a silky sheen to the (oliation su#(ace1 Phyllites 0ith both a (oliation and lineation a#e .e#y common1Phyllite:ab/latePhylliteM0%1M2R3$4/Maming Metamorphic Rocks6aming Metamorphic Rocks6/chist6a metamo#,hic #ock e4hibitin/ a schistosity1 5y this de(inition schist is a b#oad te#m- and slates and ,hyllites a#e also ty,es o( schists1 In common usa/e- schists a#e #est#icted to those metamo#,hic #ocks in 0hich the (oliated mine#als a#e coa#se enou/h to see easily in hand s,ecimen1 M0%1M2R3$4/Maming Metamorphic Rocks6aming Metamorphic Rocks6&neiss6a metamo#,hic #ock dis,layin/ /neissose st#uctu#e1 Gneisses a#e ty,ically laye#ed 2also called banded)- /ene#ally 0ith alte#natin/ (elsic and da#ke# mine#al laye#s1 Gneisses may also be lineated- but must also sho0 se/#e/ations o( (elsicmine#al#ich and da#kmine#al#ich concent#ationsM0%1M2R3$4/Maming Metamorphic Rocks6aming Metamorphic Rocks6Metamorphic rocks may "e named "ased on6 protolithology structure 9type of foliation) structure and:or composition 9nonfoliated ;comp.) chemistry'omposition may "e used for some rocks which are structurally nonfoliatedM0%1M2R3$4/Maming Metamorphic Rocks6aming Metamorphic Rocks6&ranofels ! a comprehensi#e term for anyisotropic rock 9a rock with no preferredorientation; aka granulites)$ornfels ! a type of granofels that is typically dark,#ery fine!grained andcompact, and occurs incontact aureolesMar"le ! composed predominantly of calcite ordolomite; protolith is typically limestoneor dolomite.uart+ite ! composedpredominantly of *uart+;protolith is typically sandstone1mphi"olite 8 composed primarily of horn"lendeand plagioclase; may also "e foliated, e.g.amphi"olite gneiss Mar"le.uart+iteM0%1M2R3$4/Maming Metamorphic Rocks6aming Metamorphic Rocks6Metamorphic rocks may "e named "ased on6 protolithology structure 9type of foliation) structure and:or composition 9nonfoliated ;comp.) chemistryM0%1M2R3$4/Maming Metamorphic Rocks6aming Metamorphic Rocks6'ommon metamorphic rx fall into < chemical classes 9approximated "y mineralogy)6 3elitic 8 deri#ati#es of aluminoussediments, e.g. shales, mudstones .uart+o!feldspathic 8 deri#ati#e of *uart+and:or feldspar!rich rocks such as arenites, felsic igneous rx 'alcareous 8 deri#ati#es of calcareous sediments Mafic 8 deri#ati#es of mafic to intermediateigneous rocks Magnesian 8 deri#ati#es of ultramafic rx Ferruginous 8 deri#ati#es of Fe!richprotoliths, usually sedimentary M0%1M2R3$4/Maming Metamorphic Rocks6aming Metamorphic Rocks62ther names6 there are a num"er of names used for #eryspecific rock types, e.g.serpentinite, skarn,blueschist, greenschist, mylonite, eclogite, cataclasite 8 will deal with laterModifiers6names usually modified "ased on6 mineralogye.g. mica schist, tourmaline schist chemistrye.g. magnesian schist, ferruginous slate protolithologye.g. granite gneiss, pelitic hornfelsTypes of Metamorphic RocksFOLIATEDThe common foliated rocks in the order of increasing grain size are SLATE PHYLLITE SHIST !"EISS"O"#FOLIATED$%artzites and Hornfels-0),--$12+*0,/$oliasiSlate schistgneiss textureCLASSIFYING M!AM"R#$IC R"C%S!&!'R( the size, shape and distribution of particles in a rock te)t*re is determined +y grade of metamorphism Low grade( ,-../0...C1 and 2o3 press*res ,from 4/5 ki2o+ars1Intermediate grade( ,6../5... c1 occ*rs at a 7ariety of temperat*res and press*res8High grade( at higher temperat*res ,5../4....C1 and at press*res of 9 4-/4: ki2o+ars F"LIA!; !&!'RSFoliated texture( more press*re and minera2 grains rea2ign themse27es and gro3 into 2arger crysta2s !hree types of fo2iated te)t*re( )ock or -laty 0e&ture -chistosity .neissic 0e&tureR"C% < SLA!Y !&!'R / SLA!Shale metamorphosed to Slate( c2ay minera2s ,sta+2e at s*rface temperat*res and press*res1 +ecome *nsta+2e and recrysta22i=e into mica crysta2s Slate is formed *nder Lo3/Grade MetamorphismSC$IS!"CI!Y / SC$IS!More e)treme press*res and temperat*res( mica crysta2s gro3 e7en 2arger / 9 4 cm in diameter8 rock has >sca2y? appearance /schistosity, referred to as a SchistSchists form *nder Intermediate/Grade MetamorphismSchists named for the minera2 constit*ents in the parent rock( mica schisttalc schistgarnet schistGNISSIC !&!'R / GNISSLight and dark si2icate minera2s separate and re/a2ign themse27es into +ands Rocks 3ith this te)t*re are ca22ed .neiss .neiss forms from $igh Grade Metamorphism!ypica2 @parentA rocks for .neissgranite dioritegabbro shale8313%$12+*0,/ 0,405),-Rocks 3ith on2y one minera2 metamorphose 3itho*t a 7isi+2y fo2iated te)t*re Limestone metamorphoses into Marble as the inter2ocking ca2cite crysta2s gro3 2argerQuartz Sandstone metamorphoses into QuartziteM!AM"R#$IC NBIR"NMN!S CONTCT M!TMO"#$%SM Metamorphism of a rock to*ched +y the intense heat of migrating magma8 "!G%ONL M!TMO"#$%SM &urial metamor'hism ( occ*rs 3hen rocks are o7er2ain +y more than 5 mi2es of rock or sediment )ynamothermal metamor'hism % occ*rs 3hen rocks are ca*ght +et3een t3o con7ergent p2ates d*ring mo*ntain +*i2ding OT$!" M!TMO"#$%C !N*%"ONM!NTS $ydrothermal metamor'hism % chemica2 a2teration of pree)isting rocks +y hot sea3ater near seaCoor spreading or s*+d*ction =ones +ault metamor'hism / occ*rs as rocks grinding past one another create a form of directed press*reD as 3e22 as considera+2e frictiona2 heat Shock metamor'hism - occ*rs 3hen a meterorite strikes the arth s*rfaceD res*2ting in tremendo*s press*res and temperat*res at the impact sites8 !he >shocked? minera2s do not fract*reD +*t rather recrysta22i=e SLATY LEA&A!E-%s%all'formedd%ringtheearl'stageof Lo(#grade )etamor*hism d%e to lithostatic stress+-"e(sheet#str%ct%remineralstendsto,e *aralleltothe,edding*lanesd%ring metamor*hism+-ho(e-er.f%rtherdee*,%rial alongthecontinentalmargin/ com*ressionalforces(illca%se deformation 0folding1+-hence.thesheetmineralsas(ell asfoliation(illnolonger,e *aralleltothe,edding*lanes. s%cht'*eoffoliationinfine grainedrocksiscalledslaty cleavage.ShaleSlate67822+0,--2s%all'associated(ithintermediategradeof metamor*hism/(herethemineralgrainsgro(slargein size as com*are to that seen in slates-Thisde-elo*sa*rono%ncedfoliation(herethe*referred oriented minerals are seen+SHISTOSE ST32T23E-%s%all' formed d%ring intermediate and high grade metamor*hism -!rainsizeincreasesandcan,eseen,'nakede'e/grainstendsto enlarge(ithincreasinggradeofmetamor*hism/thecoarsegrained sheet#str%ct%re minerals sho( *referred orientation-grainsizeisthemaindifference,et(eentheslat'str%ct%reand schistos str%ct%re+.3,+--+C -0)5C05),-%s%all'associated(ithhigh#graderegionalmetamor*hism0(here differential stress *re-ails I+e+ tectonic forces1-(herethesheetsilicatesandothermineralslike 4%artz5felds*ars5horn,lende5*'ro6enearesegregatedindistinct,ands in the rocks# kno(n as gneissic banding. C2assiEcation of Metamorphic rocks +ased on te)t*reFstr*ct*res67822+0,%similartoslate,butslightlycoarser phyllosilicate grains%grainscanbeseeninhandspecimen,giving silk appearance to cleavage surfaces%oftencleavageplaneslessperfectlyplanar than slatesSLATE #strongl' clea-ed rock#clea-age *lanes are de-elo*ed d%e to orientation of fine *h'llosilcate grains eg+ )%sco-ite. ,iotite. chlorite etc+#indi-id%al grains too fine to ,e -isi,le (ith naked e'e#o-erall d%ll a**earance -C7+-0/para22e2a2ignmentofmoderate2ycoarsegrains ,fa+ricGschistocity1/grains are 7isi+2e +y eye/main2yphy22osi2icatesandotherminera2ss*chas horn+2endeD kyanite etc8!"EISS#coarse grained rock 0grain size se-eral millimetres1 and#foliated 0*lanar fa,ric7 either schistosit' or com*ositional la'ering1#tendenc'fordifferentmineralstosegregateintola'ers*arallelto foliation0gneissicla'ering17t'*icall'4%artzandfelds*arrichla'ers tend to se*arate from micaceo%s la'ers+ &arieties7 ##Orthogneiss7 rocks formed from Igneo%s rocks##*aragneiss7rocksformedfromSedimentar'rocks #metasedimentar' gneisses$2A3TI8ITE-it comprise equidimensional minerals viz. quartz and feldsparsNon foliated; show GRANULOSE STRUCTURE #Im*ortance of )etamor*hic rocks- SLATESFine grained im*ermea,le. clea-a,le and softIncom*etent/ cannot (ithstand great loads9%t since the' are im*ermea,le and s*lit easil'/ thin large sized sla,s of %niform thickness can ,e e6tracted for roofing *%r*ose+Economic im*ortance7 Since the' are ,ad cond%ctor of electricit' %sed in electrical ind%stries for s(itch ,oard ,aseslate67822+0,--2s%all'associated(ithintermediategradeof metamor*hism/(herethemineralgrainsgro(slargein size as com*are to that seen in slates-Thisde-elo*sa*rono%ncedfoliation(herethe*referred oriented minerals are seen+phyllite!"EISS!neissicrocksarerichinSILIAi+e+*redominantl' $%artzandFelds*arsalong(ithgarnet.*'ro6ene. Horn,lende etc+"on#*oro%s and im*ermea,le nat%re increases the strength of the rockFoliated character to some e6tend im*ro-es (orka,ilit'Load*er*endic%lartofoliated*lanesgi-esmorestronger fo%ndationgneissIf mineral assem,lage is more or less similar to!ranite 0(ith less : mafic minerals1 then7It is %sed as ,%ilding stoneAs aggregate for making concreteAs road metals etc+SHIST)ainl' com*osed of *rismatic or *lat' minerals. (hich contri,%tes in de-elo*ment of Schistose Str%ct%re+ Eg+ Horn,lende. to%rmaline. sillimanite etc 0*rismatic1/ chlorite. m%sco-ite. ,iotite. talc. k'anite etc+ 0*lat'1lea-a,le nat%re of Schists is the main reason for their (eakness/ the' are incom*etent$2A3T8ITESA"DSTO"E0com*osedof4%artz5felds*ars5felds*athoidminerals1 (hen %nder go metamor*hism res%lt into $%artzite+!ran%lose te6t%re5str%ct%re 0!rano,lastic1 makes them most com*etent rock amongst all other metamor*hic rocks+9eca%semetamor*hismofSst+3es%ltdisa**earanceofcementing material. ,edding *lanes. fossil content etc+$%artzitesarecom*act.hardandstrong/-er'less*oro%sandless *ermea,le than the *arent Sst+Predominanceof$%artzmakestherock-er'hardands%ita,lefor road metal/ can ,e %sed as concrete aggregate etc+Acts as strong fo%ndation for an' E str%ct%re+ quartzite)A39LELatin word Maror!" S#ining stone.alcareo%s metamor*hic rockTho%ghitsho(sgran%losestr%ct%reitisnotashardas$%artzite ,eca%seofitsalcareo%scom*osition/,%tcan(ithstandreasona,le load+D%etoits*leasantcolo%rand,rillianta**earance(hen*olisheditis e6tensi-el' %sed as ,%ilding stone+alcite"a#ble