Chapter 2 Rock第二章 岩石.ppt

Chapter2Rock第二章岩石,1造岩矿物的概念Sincemineralsarethebuildingblocksofrocks,itisimportantthatyoulearntoidentifythemostcommonvarieties.Mineralscanbedistinguishedusingvariousphysicaland/orchemicalcharacteristics,but,sincechemistrycannotbedeterminedreadilyinthefield,thephysicalpropertiesofmineralsareusedtoidentifythem.,2-1Themainmineralsintherock造岩矿物,Physicalpropertiesofmineralsinclude♥Crystal（晶形）♥Hardness（硬度）relativetoasteelbladeoryoufingernail,♥colour真色，假色，它色♥Luster（光泽）♥Streak条痕thecolourwhenamineralisgroundtoapowder.♥cleavage（解理）,2矿物的物理性质,Quartzishard-itcaneasilyscratchasteelknifeblade.Inmanyrocks,quartzgrainsareirregularinshapebecausecrystalfacesarerareandquartzdoesnothaveacleavageie,itdoesnotbreakonregularflatfaces.,（1）Quartz石英,Quartzisaglassylooking,transparentortranslucentmineralwhichvariesincolourfromwhiteandgreytosmoky.Whenthereareindividualcrystalstheyaregenerallyclear,whileinlargermassesquartzlooksmoremilkywhite.油脂光泽,2常见矿物介绍,Feldsparisalsohardbutcanbescratchedbyquartz.Feldsparinigneousrocks（火成岩）swelldevelopedcrystalswhichareroughlyrectangularinshape,andtheycleaveorbreakalongflatfaces.Thegrains,incontrasttoquartz,oftenhavestraightedgesandflatrectangularfaces,someofwhichmeetatrightangles.,（2）Feldspar（长石）,Feldsparistheothercommon,light-colouredrock-ingmineral.Insteadofbeingglassylikequartz,itisgenerallydulltoopaque（不透明）withaporcelain-likeappearance.Colourvariesfromred,pinkorthoclase正长石,andwhitetogreen,greyplagioclase斜长石.,Plagioclase斜长石,Orthoclase正长石,Themostcommonamphiboleishornblende（角闪石）.Hornblendeisquitesimilartoaugite（普通辉石）inthatbotharedarkminerals,howeverhornblendecrystalsaregenerallylonger,thinnerandshinierthanaugiteandthemineralcross-sectionsarediamond-shaped.,,（3）Amphibole（闪石）,Themostcommonpyroxenemineralisaugite.Augiteisgenerallydarkgreentoblackincolourandsshort,stubby（短而粗）crystalswhich,ifyoulookatanend-onsection,havesquareorrectangularcross-sections.,（4）Pyroxene辉石,Talcoccursingranular（粒状的）orfoliated（片状的）massessometimesknownassoapstone（皂石）.Itiswhitetogreen,sometimesgreyorbrownish.Itisverysoftandwillbescratchedbyafingernail.Ithasagreasyfeel（滑感）,（5）Talc（滑石）,Olivineinthejewellerytrade,isyellow-green,translucent（半透明的）andglassylooking.Crystalsarenotcommon;itusuallyoccursasroundedgrainsinigneous（火成的）rocksorasgranularmasses.Olivineisalmostashardasquartz;itdoesnothaveawell-developedcleavage.,（6）Olivine橄榄石,,Micaiseasilydistinguishedbyitscharacteristicofpeelingintomanythinflatsmoothsheetsorflakes（薄片）.Thisissimilartothecleavageinfeldsparexceptthatinthecaseofmicathecleavageplanesareinonlyonedirectionandnorightanglefacejoinsoccur.Micamaybewhiteandpearlyordarkandshiny.,（7）Mica云母,（8）Gypsumplasterstone,石膏（9）Kaolinite高岭石（10）Montmorillonite（蒙脱石）（11）Watermica（伊利石）,2-2Rock岩石,一、Theclassificationofrockaccordingtothecauseofation,岩石的基本概念一种或多种矿物组成的集合体,二、Igneousrock,1theationofigneousrock,DeepwithintheEarth,rockiskeptinamolten（融熔的）stateduetoextremetemperatureandpressure.Thismoltenrockiscalledmagma（岩浆）.Themagmaisconstantlymovingandsometimesmovesitswaytothesurfacethroughthecracks（裂缝）inthesolidrock.Onceitreachesthesurface,itiscalledlava（熔岩）.,Thelocationitpushesthroughtothesurfaceiscalledavolcano（火山）.Theopeninginthevolcanothatthelavaeruptsoutofiscalledavent出口.anyvolcanos,thereismorethanonevent.Oftenvolcanoshaveafunnel（漏斗）shapewithapitatthetop.Thispitiscalledavolcaniccrater（火山口）.Ifthiscraterbecomesverylarge,thewallsofthecratermightcollapsetoproduceafeaturecalledacaldera（喷火山口）,HowIgneousrockrockIsed,2theationstateofigneousrock（岩浆岩的产状）,3theclasscificationofigneousrock（岩浆岩的分类）,（1）Accordingtotheationstate按产状◈IntrusiveIgneousRocks（侵入岩）-usuallymediumtocoarsegrainedtextureduetoslowcooling.Typicallylightcoloured.◈ExtrusiveIgneousRocks（喷出岩）-glassyorfine-grainedduetorapidcooling.Mayhavevoidsduetodegassingofthemagma.Typicallydarkcoloured.,2AccordingtotheSilicaContentandMineralComposition根据二氧化硅含量◈AcidIgneousRocks酸性岩-silicarich65byweightcomposedmainlyoflightcolouredmineralseg.feldspars,quartz◈IntermediateIgneousRocks（中性岩）-silica50-65byweight,composedmainlyoffeldspars,somemafic（铁镁质的minerals,withsomequartz.,◈BasicIgneousRocks（基性岩）-silicapoor50byweightcontainsignificantamountsofmaficordarkcolouredferromagnesianmineralseg.olivines,pyroxenes,amphiboles,micas.Nofreequartz.,◈granite（花岗岩）Graniteisanigneousrockthatiscomposedoffourminerals.Thesemineralsarequartz,feldspar,mica,andusuallyhornblende.Granitesasmagmacoolsfarundertheearthssurface.Becauseithardensdeepunderground，itcoolsveryslowly.Thisallowscrystalsofthefourmineralstogrowlargeenoughtobeeasilyseenbythenakedeye.,4thedescriptionofmainigneousrock（岩浆岩描述）,Graniteisanexcellentmaterialforbuildingbridgesandbuildingsbecauseitcanwithstandthousandsofpoundsofpressure.Itisalsousedonumentsbecauseitweathersslowly.Engravingsinthegranitecanbereadforhundredsofyears,makingtherockmoruable.GraniteisquarriedinmanyplacesintheworldincludingtheUnitedStates.TheStateofNewHampshirehasthenickname“GraniteState“becauseoftheamountofgraniteinthemountainsofthatbeautifulstate.TheCanadianShieldofNorthAmericacontainshugeoutcroppingssurfacerocksofgranite.,◈rhyolite（流纹岩）Rhyoliteisverycloselyrelatedtogranite.Thedifferenceisrhyolitehasmuchfinercrystals.Thesecrystalsaresosmallthattheycannotbeseenbythenakedeye.Rhyoliteisanextrusiveigneousrockhavingcooledmuchmorerapidlythangranite,givingitaglassyappearance.Themineralsthatmakeuprhyolitearequartz,feldspar,mica,andhornblende.,Rhyolite流纹岩,1abyssalintrusiverock2wellcrystallization3feldspar,quartz,amphibole,◈Diorite闪长岩,◈Dioriteporphyrite（闪长玢岩）,1shallowintrusiverock,2mediancrystallization3feldspar,quartzamphibole,Daciteisanextrusiveigneousrock.Theprinciplemineralsthatmakeupdaciteareplagioclase,quartz,pyroxene,orhornblende.,Dacite安山岩,◈Dacite（安山岩）,Dacite安山岩,1abyssalintrusiverock2wellcrystallization3amphibole,phyroxenefeldspar,◈pyroxenire辉岩,1ultrabasicrock（超基性岩石）sio2452abyssalintrusiverock（深成岩）3wellcrystallization（结晶好）4olivine；pgroxene,◈olivinerock橄榄岩,Basaltsaredarkcolored,fine-grainedextrusiverock.Themineralgrainsaresofinethattheyareimpossibletodistinguishwiththenakedeyeorevenamagnifyingglass（放大镜）.Theyarethemostwidespreadofalltheigneousrocks.Mostbasaltsarevolcanicinoriginandwereedbytherapidcoolingandhardeningofthelavaflows.SomebasaltsareintrusivehavingcooledinsidetheEarthsinterior.,◈basalt玄武岩,◈Obsidian黑耀岩,Obsidianisaveryshinynaturalvolcanicglass.Whenobsidianbreaksitfractureswithadistinctconchoidal（贝壳状的）fracture.Noticeinthephototothelefthowitfractures.Obsidianisproducedwhenlavacoolsveryquickly.Thelavacoolssoquicklythatnocrystalscan.,,Whenpeoplemakeglasstheymeltsilicarockslikesandandquartzthencoolitrapidlybyplacingitinwater.Obsidianisproducedinnatureinasimilarway.Obsidianisusuallyblackoraverydarkgreen,butitcanalsobefoundinanalmostclear.,Pumiceisaverylightcolored,frothy（起泡的）volcanicrock.Pumiceisedfromlavathatisfullofgas.Thelavaisejectedandshotthroughtheairduringaneruption.Asthelavahurtles（急飞）throughtheairitcoolsandthegasesescapeleavingtherockfullofholes.,◈Pumice（浮石）,Pumiceissolightthatitactuallyfloatsonwater.Hugepumiceblockshavebeenseenfloatingontheoceanafterlargeeruptions.Somelavablocksarelargeenoughtocarrysmallanimals.,三、sedimentaryrock（沉积岩）,1theationofsedimentaryrockForthousands,evenmillionsofyears,littlepiecesofourearthhavebeeneroded--brokendownandwornawaybywindandwater.Theselittlebitsofoureartharewasheddownstreamwheretheysettletothebottomoftherivers,lakes,andoceans.Layerafterlayeroferodedearthisdepositedontopofeach.Theselayersarepresseddownmoreandmorethroughtime,untilthebottomlayersslowlyturnintorock.,HowSedimentaryRockIsed,Sedimentsaresubdividedintothreetypes（1）Clasticordetritalsediments（碎屑岩）Comprisingparticlesofvarioussizescarriedinsuspensionbywind,waterorice.Sand砂岩isanexampleofaclasticsediment.Silt（粉砂岩）andsandsizeparticlesarecarriedinsuspensionbywind,waterandice.,2theclassificationofsedimentaryrock,（2）Chemicalorprecipitatedsediments（化学岩）whicharecarriedinaqueoussolution.Salthaliteisanexampleofachemicalprecipitate.（3）Organicorbiogenicsediments（有机岩）precipitatedoraccumulatedbybiologicalagents.Manyorganismspromotetheprecipitationofcalcitetobiogenicallyprecipitatedcalcareous（含钙的）muds.,3Thetextureandstructureofsedimentaryrock沉积岩的结构和构造,沉积岩的层理构造,,沉积岩的结构特征,砂粒,孔隙,胶结物,砂粒,粘粒,粉粒,,铁饼形的,Sphericity球形度,[sfe’risiti],4thedescriptionofsedimentaryrock,Conglomeraterocksaresedimentaryrocks.Theyaremadeupoflargesedimentslikesandandpebbles（鹅卵石）.Thesedimentissolargethatpressurealonecannotholdtherocktogether;itisalsocementedtogetherwithdissolvedminerals.,◈gravelstoneconglomerate砾岩,clasticrock,◈sandstoned2-0.05mm砂岩,Sandstonerocksaresedimentaryrocksmadefromsmallgrainsofthemineralsquartzandfeldspar.Theyofteninlayersasseeninthispicture.Theyareoftenusedasbuildingstones.,◈siltstoned0.05-0.005mm粉砂岩,◈mudstoned0.005mm泥岩,kaolinite高岭石montorillonite（蒙脱石）watermica（伊利石）,MineralComposition,,Shalerockisatypeofsedimentaryrockedfromclaythatiscompactedtogetherbypressure.Theyareusedtomakebricks,◈shalestoned0.005mm页岩,Limestonerocksaresedimentaryrocksthataremadefromthemineralcalcitewhichcamefromthebedsofevaporatedseasandlakesandfromseaanimalshells.Thisrockisusedinconcreteandisanexcellentbuildingstoneforhumidregions.colorgrey,◈limestone石灰岩,◈dolomiterock白云岩,colorwhite-greymineraldolomit,◈Gypsum石膏,Gypsumrocksaresedimentaryrocksmadeupofsulfatemineralandedastheresultofevaporatingseawaterinmassiveprehistoricbasins.ItisverysoftandisusedtomakePlasterofParis,casts,molds,andwallboards.,四、Metamorphicrock（变质岩）,MetamorphicrocksaregeneratedbyrecrystallizationofeitherigneousorsedimentaryrocksbytheactionofanyorallofthefollowingPressure,Temperature,PoreFluids.,Thetypeofmetamorphicrockisdeterminedbytheparentrock（母岩）andtheP/Tconditions.Ingeneral,metamorphismcausesGrowthofnewmineralsDeationandrotationofmineralgrainsRecrystallizationofmineralsaslargergrains,1theationandclassificationofMetamorphicrocks,,变质岩的形成,,接触变质岩的形成,,区域变质岩的形成,2thedescriptionofMetamorphicrocks,◈Marble（大理岩）,Marbleismetamorphosedlimestoneordolomite.BothlimestoneanddolomitehavealargeconcentrationofcalciumcarbonateCaCO3.Marblehasmanydifferentsizesofcrystals.,Marblehasmanycolorvariancesduetotheimpurities杂质presentatation.Someofthedifferentcolorsofmarblearewhite,red,black,mottledandbanded,gray,pink,andgreen.Marbleismuchharderthanitsparentrock.Thisallowsittotakeapolishwhichmakesitagoodmaterialforuseasabuildingmaterial,makingsinktops,bathtubs,andacarvingstoneforartists.Today,headstonesaremadefrommarbleandgranitebecausebothoftheserocksweatherveryslowlyandcarvewellwithsharpedges.,◈Quartzite（石英岩）,Quartziteiscomposedofsandstonethathasbeenmetamorphosed.Quartziteismuchharderthantheparentrock,sandstone.Itsfromsandstonethathascomeintocontactwithdeeplyburiedmagmas.Quartzitelookssimilartoitsparentrock.Thebestwaytotellquartzitefromsandstoneistobreaktherocks.Sandstonewillshatterintomanyindividualgrainsofsandwhilequartzitewillbreakacrossthegrains.,