實(shí)習(xí)五 巖漿巖

實(shí)習(xí)五巖漿巖（一）中酸性巖目的：1、學(xué)會(huì)巖石的鑒定和描述方法

2、掌握巖漿巖的結(jié)構(gòu)、構(gòu)造類型

3、認(rèn)識(shí)幾種主要的巖漿巖類巖石內(nèi)容：1、觀察并描述：花崗巖、似斑狀花崗巖、花崗斑巖、流紋巖、偉晶巖、浮巖等

2、觀察：細(xì)晶巖、黑曜巖、珍珠巖、花崗閃長巖等巖石Rocks巖石：礦物的天然混合物或集合體。RocksarenaturalmixturesoraggregatesofmineralsHowtoIdentifyRocksRockscanbeclassifiedasigneous,metamorphic,orsedimentaryaccordingtothemannerinwhichtheywereformed.Theirspecificcharacteristicsdependonthemineralsthatconstitutethem.Basedonthisinformation,itispossibletoknowhowrocksgainedtheircolor,texture,andcrystallinestructure.Withalittleexperienceandknowledge,peoplecanlearntorecognizeandidentifysomeoftherocksthattheyoftensee.ColorThecolorofarockisdeterminedbythecolorofthemineralsthatcomposeit.Somecolorsaregeneratedbythepurityoftherock,whereasothersareproducedbytheimpuritiespresentinit.Marble,forinstance,canhavedifferentshadesifitcontainsimpurities.TextureTexturereferstothesizeandarrangementofgrainsthatformarock.Thegrainscanbethick,fine,orevenimperceptible.Therearealsorocks,suchasconglomerates,whosegrainsareformedbythefragmentsofotherrocks.Thetextureisasmall-scalepropertyofarock,butdeterminedmanyofitslarge-scaleproperties.MineralCompositionRocksarenaturalcombinationsoftwoormoreminerals.Thepropertiesofrockswillchangeinaccordancewiththeirmineralogicalcomposition.Forinstance,granitecontainsquartz,feldspar,andmica;theabsenceofanyoftheseelementswouldresultinadifferentrock.TheThreeGreatRockFamilies三大巖類：Sedimentary：沉積巖

Hasobviousstratification層理

Verysoft(easilyscratchedbyaknife)軟

Obviouslymadeofparticlescementedtogether碎屑被膠結(jié)在一起

Containsfossils化石Igneous-Volcanic火山巖Containsnumerousbubble-likecavitiesthatmayormaynotbelinedwithminerals氣孔Hasobviousbubblyorfrothytexture氣孔Isfine-grained,uniformintexture,andhard

細(xì)粒、均勻、堅(jiān)硬GlassyorhighlyvesicularrocksarealmostalwaysigneousIgneous-Plutonic侵入巖Madeofdiscretemineralgrainslockedtogether(maybeloosenedbyweathering)Containslargecrystalsinafiner-grainedmassRockmassobviouslycutsacrossotherrockstructures.Metamorphic變質(zhì)巖Hasafinetexturewithanobviousdirectionalgrain(foliation)定向Hasobviousbands,streaksorclumpsofdifferentminerals不同礦物的條帶Ismademostlyofquartzorcalcitebutiscoarse-grainedandlackssedimentaryfeatures石英方解石Containsdistinctivemetamorphicmineralslikegarnetorkyanite特殊的變質(zhì)礦物Mayoftenhavefeaturesoforiginalrockbutisrecrystallizedorchemicallychanged.IgneousRocksandMagma火成巖和巖漿火成巖的產(chǎn)狀分類噴出巖－火山巖侵入巖－深成巖侵入巖－淺成巖5kmIgneousRocksare

formedbycrystallizationfromaliquid,ormagma.

Theyincludetwotypes：

Volcanicorextrusive

igneousrocksformwhenthemagmacoolsandcrystallizesonthesurfaceoftheEarth

Intrusiveorplutonic

igneousrockswhereinthemagmacrystallizesatdepthintheEarth.巖漿巖的結(jié)構(gòu)巖漿巖的結(jié)構(gòu)按照結(jié)晶程度劃分顯晶質(zhì)結(jié)構(gòu)隱晶質(zhì)結(jié)構(gòu)流紋巖玻璃質(zhì)結(jié)構(gòu)黑曜巖斑狀結(jié)構(gòu)斑狀和似斑狀結(jié)構(gòu)：區(qū)別主要在基質(zhì)的粒度斑狀結(jié)構(gòu)斑晶基質(zhì)斑晶似斑狀結(jié)構(gòu)斑晶基質(zhì)文象結(jié)構(gòu)(GraphicTexture)石英呈一定的外形(如象形文字）有規(guī)律地鑲嵌在鉀長石中。SomeIgneousRocksAreNamedonTexturalCriteria結(jié)構(gòu)構(gòu)造的命名Scoria:Porous火山渣Pumice浮巖Obsidian-Glass黑曜巖Tuff-CementedAsh火山灰Breccia-CementedFragments角礫巖Pegmatite-ExtremelyLargeCrystals偉晶巖Aplite-SugaryTexture,Quartz&Feldspar細(xì)晶巖Porphyry-FineMatrix,LargeCrystals斑巖巖石的構(gòu)造均一塊狀構(gòu)造斑雜構(gòu)造條帶狀構(gòu)造流動(dòng)構(gòu)造氣孔構(gòu)造杏仁構(gòu)造枕狀構(gòu)造塊狀構(gòu)造條帶狀構(gòu)造流紋構(gòu)造氣孔狀構(gòu)造杏仁構(gòu)造化學(xué)組成及分類以氧化物形式表示：如SiO2、Al2O3、CaO、Na2O、K2O等等SiO2是最重要的組分，是巖石分類的最主要指標(biāo)，可以劃分為：酸性巖，SiO2>65％中性巖，65%>SiO2>52％基性巖，52%>SiO2>45％超基性巖，SiO2<45％巖石中的礦物組成主要為硅酸鹽礦物，分為淺色和暗色兩類：淺色礦物：斜長石、正長石、石英暗色礦物：橄欖石、輝石、角閃石、黑云母不同酸性程度的巖石具有特征的礦物組成ThegeologistN.L.Bowenfoundthatmineralstendtoforminspecificsequencesinigneousrocks,橄欖石輝石角閃石黑云母石英白云母鉀長石鈉長石中長石鈣長石巖石的觀察描述細(xì)粒顏色玻璃質(zhì)或隱晶質(zhì)結(jié)構(gòu)構(gòu)造粗粒：顏色結(jié)構(gòu)、構(gòu)造主要礦物成分及其鑒定特征和含量其它斑狀結(jié)構(gòu)顏色斑狀或似斑狀結(jié)構(gòu)斑晶：成分及其鑒定特征、大小、含量基質(zhì)：特征及含量構(gòu)造其它實(shí)習(xí)五巖漿巖（一）中酸性巖目的：1、學(xué)