Nyob rau hauv magmatism nkag siab tag nrho ntawm phenomena txuam nrog kev tsim, evolution ntawm cov muaj pes tsawg leeg thiab txav ntawm magmas mus rau saum npoo ntawm lub ntiaj teb. Magmatism yog ib qho kev sib sib zog nqus tseem ceeb tshaj plaws hauv lub ntiaj teb sab hauv. Raws li daim ntawv ntawm manifestation, magmatism muab faib ua intrusive thiab effusive. Qhov sib txawv ntawm lawv feem ntau txiav txim siab cov txheej txheem ntawm kev tsim pob zeb.
Lub tswvyim ntawm magma
Magma yog cov kua dej kub-silicate yaj uas tsim nyob rau hauv cov chav sib sib zog nqus, feem ntau nyob rau hauv lub mantle sab saud (asthenosphere) thiab ib nrab nyob rau hauv cov khaubncaws sab nraud povtseg ntawm lub ntiaj teb crust. Kev tsim ntawm magma chamber tshwm sim thaum qee qhov tseem ceeb ntawm kev siab thiab kub ua ke. Xws li thawj magma muaj homogeneous muaj pes tsawg leeg, suav nrog cov khoom hauv qab no: kua (melt), uas cov pa roj lossis cov dej tsis hloov pauv (kua) yaj. Kuj muaj qee yamkhoom crystalline khoom. Thaum koj txav mus rau saum npoo, thawj magma hloov zuj zus nyob ntawm cov xwm txheej tshwj xeeb.
Kev hloov pauv ntawm magma suav nrog ntau hom txheej txheem. Ua ntej, nws ntsib ntau yam kev sib txawv:
- kev cais, uas nws cais ua cov kua dej tsis sib haum;
- crystalization sib txawv. Cov txheej txheem tseem ceeb tshaj plaws no yog txuam nrog nag lossis daus (crystallization) ntawm qee cov tebchaw los ntawm amorphous yaj ntawm ntau qhov sib xyaw ntawm qhov kub thiab txias.
Thib ob, magma hloov nws cov tshuaj muaj pes tsawg leeg los ntawm kev cuam tshuam nrog cov pob zeb. Qhov tshwm sim no hu ua contamination.
Crystalization txheej txheem hauv magma
Vim tias magma yog ib qho sib xyaw ntawm ntau yam khoom thiab hloov pauv, cov crystallization ntawm nws cov khoom yog txheej txheem nyuaj heev. Nws feem ntau muab faib ua peb theem tseem ceeb:
- Kub kub thaum ntxov magmatic theem. Nyob rau theem no, high-density hlau- thiab magnesium-muaj cov zaub mov poob tawm ntawm magma. Lawv nyob thiab sib sau nyob rau hauv qab ntawm lub magma chamber.
- Nruab nrab-kub lub ntsiab magmatic theem, uas lub ntsiab ntawm pob zeb tsim, xws li feldspars, quartz, mica, pyroxenes, amphiboles. Calcium precipitates, feem ntau ntawm silicon thiab txhuas. Crystallization nyob rau theem no twb nrog rau qhov tsis txaus ntawm qhov chaw nyob rau hauv lub magma chamber, yog li cov minerals uas tshwm sim yog finer-grained.
- Kub-kub lig magmatic (pegmatite)theem. Nyob rau theem no, lub mobile thiaj li hu ua pegmatite magma seem, enriched nyob rau hauv volatile Cheebtsam, kis tau los ntawm cov kab noj hniav thiab kab nrib pleb nyob rau hauv lub magma chamber, pab mus rau recrystallization ntawm host pob zeb. Pegmatite leeg yog tus cwj pwm los ntawm kev tsim cov muaju loj uas tuaj yeem loj hlob mus rau ib leeg. Cov theem no ciam teb thiab zoo sib xws rau theem hydrothermal ntawm cov pob zeb tsim.
Volcanism thiab plutonism
Muaj ntau hom kev tshwm sim ntawm magmatism li intrusive thiab effusive. Qhov sib txawv ntawm lawv nyob rau hauv cov xwm txheej ntawm evolution ntawm magmas thiab qhov chaw ntawm lawv solidification. Qhov kawg tseem ceeb ua lub luag haujlwm tseem ceeb.
Effusive magmatism yog txheej txheem thaum lub sijhawm magma nce mus txog saum npoo ntawm lub ntiaj teb los ntawm cov khoom siv channel, nce mus rau saum toj, tsim hluav taws xob, thiab khov. Lub magma tawg yog hu ua lava. Thaum nws ncav cuag qhov chaw, nws hnyav poob nws cov khoom tsis haum. Solidification kuj tshwm sim sai heev, qee hom lavas tsis muaj sijhawm los crystallize thiab solidify nyob rau hauv lub xeev amorphous (volcanic iav).
Intrusive magmatism (plutonism) txawv ntawm qhov magma tsis ncav cuag qhov chaw. Intruding nyob rau hauv ib txoj kev los yog lwm yam mus rau lub overlying horizons ntawm host pob zeb, magma solidifies ntawm qhov tob, tsim intrusive (plutonic) lub cev.
Kev faib tawm ntawm kev nkag mus
Kev sib raug zoo ntawm tus tswv pob zeb nrog cov khoom ntawm cov magmatism intrusive thiab hom intrusive lub cev yog txawv raws li ntau yam, tshwj xeeb, xws li:
- Tsim qhov tob. Muaj ze-nto (subvolcanic), nruab nrab-dav (hypabyssal) thiab tob (abyssal) intrusion.
- Qhov chaw txheeb ze rau tus tswv pob zeb. Raws li qhov kev ntsuas no, embedded arrays muab faib ua consonant (concordant) thiab discordant (discordant).
Tsis tas li ntawd, qhov xwm txheej ntawm kev cuam tshuam magmatism thiab hom kev nkag tau raug cais raws li cov yam ntxwv xws li qhov piv ntawm cov qauv ntawm lub cev plutonic rau qhov chaw sib cuag (conformal thiab disconformal), cuam tshuam rau tectonic txav, duab, loj. ntawm pawg ntseeg, thiab lwm yam.
Cov txheej txheem los txheeb xyuas ntau hom kev tawm tsam magmatic muaj feem cuam tshuam zoo. Piv txwv li, nyob ntawm tus qauv ntawm lub stratum enclosing, qhov tob thiab mechanism ntawm tsim ntawm magmatic massif thiab lwm yam manifestations ntawm intrusive magmatism, cov duab ntawm intrusion yuav txawv heev.
Mechanisms for the introduction of magma into the rock mass
Magma tuaj yeem nkag mus rau hauv tus tswv stratum hauv ob txoj hauv kev tseem ceeb: raws lub dav hlau ntawm stratification ntawm sedimentary stratum lossis raws cov kab nrib pleb uas twb muaj lawm hauv pob zeb.
Nyob rau hauv thawj rooj plaub, nyob rau hauv lub siab ntawm magma, cov khaubncaws sab nraud povtseg ntawm lub ru tsev nce - lub overlying cheeb tsam ntawm lub thickness - los yog, conversely, raws li ib tug tshwm sim ntawm lub zog ntawm intruding magma, lub hauv paus txheej. sag. Qhov no yog li cas consonant intrusion yog tsim.
Yog tias magma nkag mus rau sab saud, txhaws thiab nthuav tawm cov kab nrib pleb, tawg los ntawm cov txheej txheem thiab cov pob zeb vov tsev, nws tus kheej tsim cov kab noj hniav uas yuav nyob hauv lub cev. Nyob rau hauv no txoj kev, unconformably tshwm simplutonic lub cev.
Suab ntawm embedded igneous masses
Raws li txoj hauv kev tshwj xeeb raws li cov txheej txheem ntawm kev nkag mus rau magmatism, cov ntaub ntawv ntawm lub cev nkag tuaj yeem muaj ntau haiv neeg. Qhov tshwm sim tsis sib haum xeeb feem ntau tshwm sim igneous massifs yog:
- Dike yog ib lub phaj zoo li lub cev dipping uas hla cov strata. Cov dikes ntev dua li tuab, thiab qhov chaw sib cuag yuav luag sib luag. Dikes tuaj yeem muaj qhov sib txawv - los ntawm kaum ntawm metres mus rau ntau pua mais ntawm qhov ntev. Cov duab ntawm dikes kuj tuaj yeem ua voj voog lossis radial, nyob ntawm qhov chaw ntawm cov kab nrib pleb uas muaj magma.
- Ib leeg yog ib lub cev me me ntawm ib lub cev tsis sib xws, ceg tawv.
- qia yog ib kab-zoo li lub cev uas muaj ntsug lossis qhov chaw sib sib zog nqus.
- Batholith yog ntau yam kev cuam tshuam loj tshaj plaws. Batholiths tuaj yeem ua tau ntau pua lossis ntau txhiab mais ntev.
Lub cev sib tshooj kuj muaj ntau hom. Ntawm lawv feem ntau pom:
- Sill yog kev nkag mus hauv txaj uas nws qhov chaw sib cuag yog sib npaug rau cov txaj txaj.
- Lopolith yog ib qho kev sib tw lenticular, convex tig down.
- Laccolith yog lub cev zoo ib yam, sab convex uas nyob rau saum toj, zoo li lub kaus mom nceb. Mount Ayu-Dag hauv Crimea yog ib qho piv txwv ntawm gabbroid laccolith.
- Phacolite yog lub cev nyob rau hauv lub quav ntawm tus tswv tsev pob zeb trough.
Intrusion Contact Zone
Kev tsim ntawm plutonic lub cev yog nrog los ntawm cov txheej txheem nyuaj ntawm kev sib cuam tshuam ntawm tus ciam teb nrog cov stratum. Thaj chaw ntawm endocontact thiab exocontact yog tsim raws li qhov chaw tiv tauj.
Endocontact hloov pauv tshwm sim hauv qhov cuam tshuam vim kev nkag mus ntawm tus tswv tsev pob zeb rau hauv magma. Yog li ntawd, magma nyob ze ntawm qhov kev sib cuag tau hloov tshuaj lom neeg (kev sib kis) uas cuam tshuam rau kev tsim cov ntxhia.
thaj chaw exocontact tshwm sim nyob rau hauv lub pob zeb tus tswv tsev vim yog cov thermal thiab tshuaj lom neeg los ntawm magma thiab yog tus cwj pwm los ntawm cov txheej txheem nquag ntawm metamorphism thiab metasomatism. Yog li, magma yam tsis muaj zog tuaj yeem hloov cov ntxhia hauv thaj chaw exocontact nrog cov sib xyaw ua ke, tsim cov hu ua metasomatic halos.
Cov tshuaj ntxhia ua los ntawm cov khoom tsis sib haum xeeb tuaj yeem tuaj yeem crystallize ncaj qha rau hauv thaj chaw tiv tauj. Cov txheej txheem no ua lub luag haujlwm tseem ceeb hauv kev tsim, piv txwv li, micas, thiab nrog kev koom tes ntawm dej, quartz.
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intruction magmatism thiab sab pob zeb
Pob zeb tsim los ntawm qhov sib sib zog nqus magma crystallization yog hu ua intrusive, lossis plutonic. Effusive (volcanic) pob zeb yog tsim thaum magma erupts rau saum npoo ntawm lub ntiaj teb (los yog nyob rau hauv dej hiav txwv pem teb).
Intrusive thiab effusive magmatism ua rau cov pob zeb zoo sib xws hauv cov ntxhia pob zeb. Kev faib tawm ntawm cov pob zeb tsis pom kev los ntawm kev sib xyaw yog ua raws cov ntsiab lus ntawm silica SiO 2. Raws li cov txheej txheem no yugsubdivided rau hauv ultrabasic, yooj yim, nruab nrab thiab acidic. Cov ntsiab lus silica hauv koob nce los ntawm ultramafic (tsawg dua 45%) pob zeb mus rau acidic (ntau dua 63%). Hauv txhua chav kawm, pob zeb sib txawv hauv alkalinity. Cov pob zeb intrusive tseem ceeb raws li qhov kev faib tawm no ua cov kab hauv qab no (volcanic analogue hauv brackets):
- Ultrabasic: peridotites, dunites (picrites);
- Main: gabbroids, pyroxenites (bas alts);
- Medium: diorites (andesites);
- Acidic: granodiorites, granites (dacites, rhyolites).
Plutonic pob zeb txawv ntawm cov effusive los ntawm cov xwm txheej ntawm qhov tshwm sim thiab cov qauv siv lead ua ntawm cov zaub mov uas tsim lawv: lawv yog cov crystalline puv (tsis muaj cov qauv amorphous), ntshiab-grained thiab tsis muaj pores. Qhov tob ntawm qhov tsim ntawm pob zeb (abyssal intrusion), qhov qeeb ntawm cov txheej txheem ntawm magma txias thiab crystallization tshwm sim, thaum tswj tau ib qho loj ntawm cov theem volatile. Cov pob zeb sib sib zog nqus no yog cov pob zeb loj dua crystalline.
Cov qauv sab hauv ntawm lub cev nkag mus
Cov qauv ntawm plutonic massifs yog tsim nyob rau hauv cov chav kawm ntawm ib tug complex ntawm phenomena koom ua ke raws li lub npe ntawm prototectonics. Nws distinguishes ob theem: prototectonics ntawm cov kua thiab khoom theem.
Nyob rau theem ua kua-theem, thawj kab txaij thiab linear textures ntawm lub cev tshwm sim. Lawv muaj kev cuam tshuam cov kev taw qhia ntawm ntws ntawm intruding magma thiab lub dynamic tej yam kev mob rau orientation ntawm crystallizing minerals (piv txwv li, lub parallel kev npaj.mica crystals, hornblende, thiab lwm yam). Kev ntxhib los mos kuj tseem cuam tshuam nrog qhov chaw ntawm cov pob zeb txawv teb chaws uas poob rau hauv magma chamber - xenoliths - thiab cais cov pob zeb hauv av - schlieren.
Cov theem khoom ntawm qhov kev hloov pauv tsis txaus ntseeg yog cuam tshuam nrog kev txias ntawm cov pob zeb tshiab. Cov kab nrib pleb tshwm sim nyob rau hauv qhov loj, qhov chaw thiab tus naj npawb ntawm cov kev txiav txim los ntawm qhov chaw txias thiab cov qauv tsim nyob rau hauv cov kua theem. Tsis tas li ntawd, cov txheej txheem theem nrab tsim nyob rau hauv xws li ib tug magmatic loj vim fragmentation ntawm nws seem thiab displacements raws ruptures.
Txoj kev tshawb fawb ntawm prototectonics yog qhov tseem ceeb los qhia meej txog cov xwm txheej rau qhov chaw ntawm cov pob zeb hauv av hauv kev nkag mus thiab hauv cov pob zeb ib puag ncig.
Magmatic intrusion thiab tectonics
Pob zeb ntawm qhov chaw nkag mus tau nthuav dav hauv ntau thaj chaw ntawm lub ntiaj teb pob zeb. Qee qhov kev tshwm sim ntawm intrusive magmatism ua rau muaj txiaj ntsig zoo rau ob qho tib si hauv cheeb tsam thiab thoob ntiaj teb cov txheej txheem tectonic.
Thaum lub sijhawm sib tsoo sab av loj nyob rau hauv cov chav kawm ntawm kev ua kom lub thickness ntawm lub crust, vim active granite magmatism, loj batholiths yog tsim, piv txwv li, lub Gangdis batholith nyob rau hauv lub Trans-Himalayas. Tsis tas li ntawd, kev tsim ntawm cov da dej loj loj yog txuam nrog cov active continental margins (Andean batholith). Feem ntau, silicic magma intrusion ua lub luag haujlwm tseem ceeb hauv cov txheej txheem hauv roob.
Thaum lub pob zeb yog ncab, cov kab sib txuas ntawm cov pas dej ua ke feem ntau tsim. Cov koob no tau pom nyob hauv nruab nrab ntug dej hiav txwv ridges.
Sills yog ib qho ntawm cov yam ntxwv ntawm intracontinental magmatic intrusion. Lawv kuj tuaj yeem muaj qhov loj - mus txog ntau pua mais. Feem ntau magma, nkag mus ntawm cov txheej ntawm cov pob zeb sedimentary, tsim ob peb txheej ntawm sills.
Kev sib sib zog nqus magmatic thiab cov zaub mov
Vim qhov peculiarities ntawm crystallization nyob rau hauv cov txheej txheem ntawm intrusive magmatism, ore minerals yog tsim rau chromium, hlau, magnesium, npib tsib xee, raws li zoo raws li haiv neeg platinoids nyob rau hauv ultrabasic pob zeb. Nyob rau hauv cov ntaub ntawv no, hnyav hlau (kub, lead, tin, tungsten, zinc, thiab lwm yam) tsim soluble tebchaw nrog volatile magma Cheebtsam (piv txwv li, dej) thiab mloog zoo nyob rau hauv lub Upper cheeb tsam ntawm lub magma chamber. Qhov no tshwm sim nyob rau hauv thaum ntxov theem ntawm crystallization. Nyob rau theem tom ntej, lub pegmatite seem ntawm lub xov tooj ntawm tes uas muaj lub ntiaj teb tsis tshua muaj thiab cov ntsiab lus tsis tshua muaj cov ntaub ntawv hauv cov hlab ntsha hauv cov pob txha tawg.
Yog li ntawd, Khibiny ntawm Kola Peninsula yog laccolith, nthuav tawm los ntawm kev yaig ntawm cov stratum enclosing. Lub cev no yog tsim los ntawm nepheline syenites, uas yog ib qho ore rau txhuas. Lwm qhov piv txwv yog Norilsk sill intrusion nplua nuj nyob rau hauv tooj liab thiab npib tsib xee.
Cov chaw sib cuag kuj tseem muaj txiaj ntsig zoo. Cov nyiaj tso nyiaj kub, nyiaj, tin thiab lwm yam hlau muaj txiaj ntsig yog txuam nrog metasomatic thiab metamorphic halos ntawm kev cuam tshuam lub cev xws li Bushveld lopolith hauv South Africa, paub txog nws cov kub bearing halos.
Yog li, thaj chaw ntawm kev nkag musmagmatism yog qhov tseem ceeb tshaj plaws ntawm ntau cov zaub mov muaj txiaj ntsig.
