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(zhǎng)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(zhǎng)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(zhǎng)石、正長(zhǎng)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(zhǎng)石鈉長(zhǎng)石中長(zhǎng)石鈣長(zhǎng)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)