Nyob rau hauv lub siab, kub siab, tshem tawm los yog qhia cov khoom rau hauv pob zeb - sedimentary, magmatic, metamorphic, ib yam dab tsi - tom qab lawv tsim, cov txheej txheem ntawm kev hloov tshwm sim, thiab qhov no yog metamorphism. Cov txheej txheem zoo li no tuaj yeem muab faib ua ob pawg dav: hauv zos metamorphism thiab tob. Lub tom kawg tseem hu ua lub regional, thiab yav tas los - lub zos metamorphism. Nws nyob ntawm qhov ntsuas ntawm tus txheej txheem.
Local metamorphism
Hauv zos metamorphism yog ib pawg loj dhau lawm, thiab nws kuj tau muab faib ua hydrothermal metamorphism, uas yog, qis thiab nruab nrab kub, kev sib cuag thiab autometamorphism. Cov tom kawg yog cov txheej txheem ntawm kev hloov pauv hauv cov pob zeb igneous tom qab solidification los yog hardening, thaum lawv cuam tshuam los ntawm residual daws, uas yog cov khoom ntawm tib magma thiab circulate nyob rau hauv lub pob zeb. Piv txwv ntawm xws li metamorphism yog serpentinization ntawm dolomites, ultramafic pob zeb thiab cov pob zeb yooj yim, thiab chloritization ntawm diabases. Hom tom ntej no yog characterizedtwb yog nws lub npe.
Kev sib cuag metamorphism tshwm sim ntawm thaj tsam ntawm cov pob zeb thiab cov magma molten, thaum kub, kua (inert gases, boron, dej) los ntawm magma act. Ib qho halo lossis cheeb tsam ntawm kev sib cuag tuaj yeem yog los ntawm ob mus rau tsib mais ntawm cov magma solidified. Cov pob zeb ntawm metamorphism feem ntau nthuav tawm metasomatism, qhov twg ib pob zeb lossis pob zeb tau hloov los ntawm lwm qhov. Piv txwv li, hu rau skarns, hornfelses. Cov txheej txheem hydrothermal ntawm metamorphism tshwm sim thaum cov pob zeb hloov pauv vim cov dej thermal daws teeb meem uas tau tso tawm los ntawm kev sib zog thiab crystallization ntawm kev tawg. Ntawm no, ib yam nkaus, cov txheej txheem ntawm metasomatism yog qhov tseem ceeb heev.
Regional metamorphism
Lub cheeb tsam metamorphism tshwm sim nyob rau thaj chaw loj uas lub ntiaj teb lub pob zeb yog txawb thiab yog submerged nyob rau hauv kev cuam tshuam ntawm tectonic txheej txheem nyob rau hauv loj cheeb tsam mus rau ib tug tob. Qhov no ua rau muaj kev kub ntxhov tshwj xeeb thiab kub siab. Lub cheeb tsam metamorphism hloov cov limestones yooj yim thiab dolomites rau hauv marbles, thiab granites, diorites, syenites rau hauv granite gneisses, amphibolites, thiab schists. Qhov no yog vim qhov tseeb tias nyob rau nruab nrab thiab qhov tob tob xws li qhov ntsuas kub thiab qhov ntsuas siab uas lub pob zeb softens, melts thiab ntws dua.
Pob zeb ntawm metamorphism ntawm hom no yog qhov txawv los ntawm lawv txoj kev taw qhia: thaum loj textures ntws, lawv dhau los ua striped, linear, shale, gneissic, thiab tag nrho cov landmarks raug txheeb ze rau cov kev taw qhia ntawm ntws. Qhov tob me me tsis tso cai rau qhov no. Vim lub metamorphism ntawm pob zeb qhia pebcrushed, shale, av nplaum los yog frayed pob zeb. Yog tias cov pob zeb hloov pauv tuaj yeem cuam tshuam nrog qee cov kab, peb tuaj yeem hais txog lub hauv paus ze-tshuaj dislocation metamorphism (dynamometamorphism). Cov pob zeb tsim los ntawm cov txheej txheem no hu ua mylonites, shales, kakirites, cataclasites, breccias. Igneous pob zeb uas tau dhau los ntawm txhua theem ntawm metamorphism hu ua orthorocks (cov no yog orthoschists, orthogneisses, thiab lwm yam). Yog tias pob zeb ntawm metamorphism yog sedimentary, lawv hu ua para-pob zeb (cov no yog paraschists lossis paragneisses, thiab lwm yam).
Metamorphism facies
Raws li tej yam kev mob ntawm qhov kev hloov pauv ntawm qhov kev hloov pauv, cov pob zeb sib txawv, qhov twg cov koom haum ntxhia sib haum rau cov xwm txheej no - kub (T), tag nrho lub siab (Р tag nrho), ib nrab siab ntawm dej (P H2O).
Hom metamorphism suav nrog tsib lub ntsiab fasciae:
1. Ntsuab slates. Qhov fascia no tshwm sim ntawm qhov kub thiab txias qis dua ob puas thiab tsib caug degrees thiab lub siab kuj tsis siab dhau - txog li 0.3 kilobars. Nws yog tus cwj pwm los ntawm biotite, chloride, albite (acid plagioclase), sericite (fine-flake muscovite) thiab lwm yam. Feem ntau cov fascia no yog superimposed ntawm cov pob zeb sedimentary.
2. Epidote-amphibolite fascia tau txais nrog qhov kub txog li plaub puas degrees thiab lub siab txog li ib kilobar. Ntawm no, amphiboles (feem ntau actinolite), epidote, oligoclase, biotite, muscovite, thiab cov zoo li yog ruaj khov. Cov fascia no tuaj yeem pom hauv cov pob zeb sedimentary.
3. Amphibolite fascia muaj nyob ntawm txhua hompob zeb - ob qho tib si igneous, thiab sedimentary, thiab metamorphic (uas yog, cov fasciae twb tau mus rau metamorphism - epidote-amphibolic los yog greenschist fascia). Ntawm no, cov txheej txheem metamorphic tshwm sim ntawm qhov kub txog li xya puas degrees Celsius, thiab lub siab nce mus txog peb kilobars. Cov fascia no yog tus cwj pwm los ntawm cov zaub mov xws li plagioclase (andesine), hornblende, almandine (garnet), diopside thiab lwm yam.
4. Granulite fascia ntws ntawm qhov kub ntawm ntau tshaj ib txhiab degrees nrog lub siab txog li tsib kilobars. Minerals uas tsis muaj hydroxyl (OH) crystallize ntawm no. Piv txwv li, enstatite, hypersthene, pyrope (magnesian garnet), labrador thiab lwm yam.
5. Eclogite fascia hla ntawm qhov kub siab tshaj plaws - ntau tshaj ib thiab ib nrab txhiab degrees, thiab lub siab tuaj yeem yog ntau tshaj peb caug kilobars. Pyrope (garnet), plagioclase, omphacite (ntsuab pyroxene) nyob ruaj khov ntawm no.
Lwm yam fascia
Ntau yam kev hloov pauv hauv cheeb tsam yog ultrametamorphism, thaum cov pob zeb yog tag nrho lossis ib nrab yaj. Yog tias ib nrab - qhov no yog anatexis, yog tias tag nrho - qhov no yog palingenesis. Migmatization kuj yog qhov txawv - cov txheej txheem nyuaj uas cov pob zeb tau tsim nyob rau hauv txheej, qhov twg cov pob zeb tsis pom kev hloov pauv nrog cov khoom siv, uas yog, cov khoom siv. Granitization yog txheej txheem dav, qhov kawg cov khoom yog ntau hom granitoids. Qhov no yog, raws li nws tau, tshwj xeeb ntawm cov txheej txheem ntawm kev tsim granite. Ntawm no peb xav tau kev qhia txog cov poov tshuaj, sodium, silicon thiab tshem tawm cov calcium, magnesium, hlau nrog cov nquag alkalis, dej thiabCov pa roj carbon dioxide.
Diaphthoresis lossis regressive metamorphism kuj yog dav. Cov koom haum ntawm cov zaub mov tsim nyob rau hauv high pressures thiab kub yog hloov los ntawm lawv cov low-temperature fasciae. Thaum amphibolite fascia yog superimposed ntawm granulite fascia, thiab greenschist thiab epidote-amphibolite fascia thiab lwm yam, diaphtoresis tshwm sim. Nws yog nyob rau hauv tus txheej txheem ntawm metamorphism uas deposits ntawm graphite, hlau, alumina, thiab zoo li tshwm sim, thiab cov concentrations ntawm tooj liab, kub, thiab polymetals yog redistributed.
Txheej Txheem thiab Yam
Cov txheej txheem ntawm kev hloov pauv thiab rov yug dua tshiab ntawm pob zeb tshwm sim nyob rau lub sijhawm ntev heev, lawv raug ntsuas hauv ntau pua lab xyoo. Tab sis txawm tsis khaus heev, yam tseem ceeb ntawm metamorphism ua rau muaj kev hloov loj heev. Lub ntsiab yam tseem ceeb yog, raws li twb tau hais lawm, lub siab thiab qhov kub thiab txias uas ua ib txhij nrog kev siv sib txawv. Qee lub sij hawm ib qho los yog lwm qhov yeej muaj zog heev. Kev kub siab kuj tuaj yeem ua rau cov pob zeb sib txawv. Nws tuaj yeem ua tiav (hydrostatic) thiab qhia unilaterally. Kev nce hauv qhov kub thiab txias ua rau muaj tshuaj lom neeg, txhua qhov kev cuam tshuam yog nrawm los ntawm kev sib cuam tshuam ntawm kev daws teeb meem thiab cov zaub mov, uas ua rau lawv cov recrystallization. Yog li pib txheej txheem ntawm metamorphism. Liab-kub magma nkag mus rau hauv lub ntiaj teb crust, exerts siab rau pob zeb, heats lawv thiab nqa nrog nws ntau yam khoom nyob rau hauv ib tug kua thiab vapor xeev, thiab tag nrho cov no pab txhawb kev cuam tshuam nrog host pob zeb.
Hom metamorphism muaj ntau haiv neeg, ib yam li ntau haiv neeg yog qhov tshwm sim ntawm cov txheej txheem no. ATTxawm li cas los xij, cov khoom qub qub tau hloov pauv thiab cov tshiab tau tsim. Thaum kub kub, qhov no hu ua hydrometamorphism. Qhov kub thiab txias ntawm lub ntiaj teb crust nce sai thiab ntse tshwm sim thaum magma nce thiab nkag mus rau hauv nws, los yog nws yuav tshwm sim los ntawm submersion ntawm tag nrho cov blocks (loj cheeb tsam) ntawm lub ntiaj teb crust thaum lub sij hawm tectonic txheej txheem mus rau qhov tob tob. Muaj ib qho tsis tseem ceeb melting ntawm pob zeb, uas txawm li cas los xij ua rau cov pob zeb thiab pob zeb hloov cov tshuaj thiab cov ntxhia hauv cov khoom thiab lub cev, qee zaum txawm tias cov duab ntawm cov pob zeb hauv av hloov pauv. Piv txwv li, hematite thiab magnetite yog tsim los ntawm hlau hydroxides, quartz los ntawm opal, thee metamorphism tshwm sim - graphite yog tau, thiab limestone dheev recrystallizes rau hauv marble. Cov kev hloov pauv no tshwm sim, txawm hais tias tau ntev, tab sis ib txwm nyob rau hauv txoj kev ua txuj ci tseem ceeb, uas ua rau tib neeg tso cov zaub mov.
Hydrothermal txheej txheem
Thaum muaj cov txheej txheem ntawm metamorphism, tsis yog kev kub ntxhov thiab kub xwb cuam tshuam rau nws cov yam ntxwv. Lub luag haujlwm loj yog muab rau cov txheej txheem hydrothermal, qhov twg ob qho tib si cov menyuam yaus cov dej tso tawm los ntawm cov dej txias magmas thiab cov dej saum npoo (vandose) koom nrog. Cov minerals feem ntau yog li tshwm sim hauv cov pob zeb metamorphosed: pyroxenes, amphiboles, garnets, epidote, chlorites, micas, corundum, graphite, serpentine, hematite, talc, asbestos, kaolinite. Nws tshwm sim tias qee cov zaub mov tseem ceeb, muaj ntau ntau ntawm lawv uas txawm tias cov npe cuam tshuam qhov loj ntawm cov ntsiab lus: pyroxene gneisses, amphibole gneisses, biotite.slates thiab zoo li.
Txhua cov txheej txheem ntawm cov ntxhia tsim - ob qho tib si magmatic, thiab pegmatite, thiab metamorphisms - tuaj yeem ua tus yam ntxwv ntawm paragenesis, uas yog, kev sib koom ua ke ntawm cov zaub mov hauv qhov xwm txheej, uas yog vim qhov sib koom ntawm lawv cov txheej txheem tsim. thiab cov xwm txheej zoo sib xws - ob qho tib si physicochemical thiab geological. Paragenesis qhia cov theem ntawm cov theem ntawm crystallization. Ua ntej - magmatic yaj, ces pegmatite remnants thiab hydrothermal emanations, los yog cov no yog sediments nyob rau hauv aqueous daws. Thaum magma los rau hauv kev sib cuag nrog cov pob zeb yooj yim, nws hloov lawv, tab sis nws hloov nws tus kheej. Thiab yog tias muaj kev hloov pauv tshwm sim hauv cov pob zeb uas tsis muaj zog, lawv hu ua endocontact hloov, thiab yog tias cov pob zeb hloov pauv, lawv hu ua exocontact hloov. Cov pob zeb uas tau dhau los ua metamorphism ua ib cheeb tsam lossis halo ntawm kev hloov pauv, qhov xwm txheej nyob ntawm qhov muaj pes tsawg leeg ntawm magma, nrog rau cov khoom thiab muaj pes tsawg leeg ntawm cov pob zeb. Qhov ntau dua qhov tsis sib xws hauv kev sib xyaw, qhov hnyav dua qhov metamorphism.
Sequence
Kev sib cuag hloov tau hais tau ntau dua nyob rau hauv cov kua qaub intrusion nplua nuj nyob rau hauv volatile cov khoom xyaw. Cov pob zeb muaj peev xwm tuaj yeem npaj tau raws li hauv qab no (raws li qib ntawm metamorphism txo qis): av nplaum thiab shales, limestones thiab dolomites (cov pob zeb carbonate), tom qab ntawd pob zeb tsis muaj zog, volcanic tuffs thiab tuffaceous pob zeb, sandstones, siliceous pob zeb. Sib cuag metamorphism nce nrog nce porosity thiab fissuring ntawm lub pob zeb, vim gases thiab vapors circulate yooj yim nyob rau hauv lawv.
Thiab ib txwm,kiag li nyob rau hauv txhua rooj plaub, lub thickness ntawm lub cheeb tsam yog ncaj qha proportional rau qhov ntev ntawm lub intrusive lub cev, thiab lub kaum sab xis yog inversely proportional nyob rau hauv qhov kev sib cuag nto ua ib tug kab rov tav dav hlau. Qhov dav ntawm kev sib cuag halos feem ntau yog ob peb puas meters, qee zaum mus txog tsib mais, nyob rau hauv cov xwm txheej tsis tshua muaj ntau dua. Lub thickness ntawm lub exocontact cheeb tsam yog ntau ntau dua li lub thickness ntawm lub endocontact cheeb tsam. Cov txheej txheem ntawm metamorphism nyob rau hauv cov hlau tsim ntawm lub exocontact cheeb tsam yog ntau ntau haiv neeg. Cov pob zeb endocontact yog nplua-grained, feem ntau porphyritic, thiab muaj ntau cov hlau uas tsis yog-ferrous. Hauv exocontact, qhov kev siv ntawm metamorphism txo qis heev, txav deb ntawm kev nkag mus.
Subspecies ntawm kev sib cuag metamorphism
Cia peb saib ze dua ntawm kev sib cuag metamorphism thiab nws ntau yam - thermal thiab metamorphism metamorphism. Li qub - thermal, nws tshwm sim nyob rau hauv ib tug ncaj tsis tshua muaj siab thiab siab kub, tsis muaj tseem ceeb influx ntawm cov khoom tshiab los ntawm ib tug twb txias intrusion. Lub pob zeb recrystallizes, qee zaum cov zaub mov tshiab tau tsim, tab sis tsis muaj kev hloov pauv tseem ceeb hauv cov tshuaj muaj pes tsawg leeg. Av nplaum shales smoothly dhau mus rau hauv hornfelses, thiab limestones rau hauv marbles. Minerals tsis tshua tsim thaum lub sij hawm thermal metamorphism, tshwj tsis yog rau qee zaus tso nyiaj ntawm graphite thiab apatite.
Metasomatic metamorphism pom meej meej ntawm kev sib cuag nrog lub cev nkag mus, tab sis nws cov kev tshwm sim feem ntau tau sau tseg hauv cov cheeb tsam uas lub cheeb tsam metamorphism tsim. Xws li kev tshwm simFeem ntau tuaj yeem cuam tshuam nrog cov pob zeb hauv av. Nws tuaj yeem yog mica, cov khoom siv hluav taws xob thiab lwm yam. Nyob rau hauv cov ntaub ntawv no, kev hloov ntawm cov minerals tau tshwm sim, uas tau pib nrog kev koom tes ntawm cov kua thiab roj cov ntsiab lus thiab tau nrog los ntawm kev hloov nyob rau hauv cov tshuaj muaj pes tsawg leeg.
Dislocation thiab cuam tshuam metamorphism
Muaj ntau lub ntsiab lus rau dislocation metamorphism, yog li yog hais txog kinetic, dynamic, cataclastic metamorphism los yog dynamometamorphism, peb tab tom tham txog tib yam, uas txhais tau hais tias cov pob zeb tsim kev hloov pauv ntawm pob zeb thaum tectonic rog ua rau. nws nyob rau thaj tsam ntawm kev cuam tshuam tsis tu ncua thaum lub roob folding thiab tsis muaj kev koom tes ntawm magma. Lub ntsiab tseem ceeb ntawm no yog hydrostatic siab thiab tsuas yog kev ntxhov siab (ib sab siab). Raws li qhov loj thiab qhov sib piv ntawm cov kev ntxhov siab no, dislocation metamorphism recrystallizes pob zeb tag nrho los yog ib nrab, tab sis tag nrho, los yog cov pob zeb raug crushed, puas, thiab kuj recrystallize. Cov zis yog ntau yam shales, mylonites, cataclasites.
Kev cuam tshuam lossis cuam tshuam metamorphism tshwm sim los ntawm lub zog loj meteoritic shock yoj. Qhov no yog tib txheej txheem ntuj uas cov hom metamorphism tuaj yeem pom. Cov yam ntxwv tseem ceeb yog qhov tshwm sim tam sim ntawd, siab ncov loj, kub siab tshaj ib thiab ib nrab txhiab degrees. Tom qab ntawd high-pressure theem teem rau ntau lub tebchaw - ringwoodite, pob zeb diamond, stishovite, coesite. Pob zeb thiab minerals yog crushed,lawv cov lattices siv lead ua puas lawm, diaplectic minerals thiab iav tshwm, tag nrho cov pob zeb yaj.
Metamorphism values
Nyob rau hauv kev kawm tob ntawm cov pob zeb metamorphic, ntxiv rau cov hom kev hloov pauv tseem ceeb uas tau teev tseg saum toj no, qee lub ntsiab lus ntawm lub tswv yim no feem ntau siv. Qhov no, piv txwv li, yog kev nce qib (lossis nce qib) metamorphism, uas ua tiav nrog kev koom tes ntawm cov txheej txheem endogenous thiab khaws cia cov khoom hauv lub xeev ntawm pob zeb yam tsis muaj kev tawg lossis yaj. Nrog rau qhov pom ntawm qhov kub thiab txias sib koom ua ke ntawm cov ntxhia hauv qhov chaw uas muaj qhov kub thiab txias, cov qauv sib npaug tshwm sim, recrystallization thiab tso tawm carbon dioxide thiab dej los ntawm cov zaub mov.
Regressive metamorphism (los yog retrograde, lossis monodiaphthoresis) kuj raug coj mus rau hauv tus account. Nyob rau hauv cov ntaub ntawv no, cov ntxhia hloov pauv yog tshwm sim los ntawm kev hloov pauv ntawm cov pob zeb metamorphic thiab magmatic pob zeb mus rau cov xwm txheej tshiab ntawm cov theem qis ntawm metamorphism, uas ua rau pom cov pob zeb tsis tshua muaj kub nyob rau hauv qhov chaw kub. Lawv tau tsim nyob rau hauv cov txheej txheem yav dhau los ntawm metamorphism. Selective metamorphism yog ib qho kev xaiv, kev hloov pauv tshwm sim xaiv, tsuas yog nyob rau qee qhov ntawm qhov sib lawv liag. Ntawm no, lub heterogeneity ntawm cov tshuaj muaj pes tsawg leeg, nta ntawm cov qauv los yog kev ntxhib los mos, thiab cov zoo li.
