Chii chinonzi Contact Metamorphism uye Examples?
Kuchinja dombo rekutanga (protolith) kuita dombo idzva nekuda kwekuchinja kwemamiriro emuviri uye emakemikari mukati megomba rePasi. Kuchinja uku kunonyanya kukanganiswa nekupisa, kumanikidzwa, uye kuvapo kwemvura (semuenzaniso, mvura inopisa, ine zvicherwa zvakawanda). Imwe yemhando dziri nyore kunzwisisa dzekuchinja dombo nekuti mashandiro aro "ari emuno" uye kwarinobva kupisa kwaro kwakajeka ikuchinja dombo. Kuchinja dombo kunoitika kana dombo rakatenderedza "rakabikwa" nekupisa kunobva ku magma kunopinda mugomba rePasi. Chinyorwa chino chinokurukura tsananguro yekuchinja dombo kunosangana, maitiro aro, hunhu hwematombo, uye mienzaniso yakajairika.
Kunzwisisa kuchinja kwekubatana kwevanhu
Kuchinja kwekubatana kwematombo (contact metamorphism) kunonyanya kuitika nekuda kwekupisa kwakanyanya kunokonzerwa nekupindira kwemagma (semuenzaniso, batholith, laccolith, sill, kana dike) inopinda mudombo riripo. Sezvo magma inopisa zvikuru ichipinda yozotonhora zvishoma nezvishoma, kupisa kunopararira kudombo riri pedyo (country rock). Matombo ari pedyo nekupindira kwematombo anosangana ne "kupisa" kwakanyanya, zvichiita kuti zvicherwa zvawo zvichinje, zvidzore, kana kuti zviite kuti zvigadzire zvicherwa zvitsva zvinogara zvakanaka pakupisa kwakanyanya.
Chinhu chikuru chinoratidza kuti contact metamorphism inonyanya kukosha pakupisa kupfuura kumanikidzwa. Kumanikidzwa kunowanzova kushoma nekuti maitiro acho anowanzoitika pakadzika pasi kusvika pakati nepakati. Nekuda kweizvozvo, matombo anokonzerwa necontact metamorphism anowanzova nechimiro chisina foliated (chisina layered), kusiyana nematombo akawanda eregional metamorphic, ayo anowanzova foliated nekuda kwekumanikidzwa kwakanangana.
Maitiro ekuchinja kwekubatana anoitika sei?
Maitiro ekubatana kwekubatana anogona kupfupikiswa muzvikamu zvakasiyana-siyana:
1. Kupinda kweMagma
Magma inokwira kubva mukati meNyika yopinda mumitswe kana munzvimbo dziri mugomba. Kupinda uku kunogona kutora chimiro chemitumbi mikuru yemagma (vanhuliths) kana machira matete (dikes/sills).
2. Kutamisirwa kwekupisa kumatombo epadivi
Nekuda kwemusiyano mukuru wekupisa, kupisa kunofamba kubva muguruva kuenda kudombo rakapoteredza kuburikidza nekufambisa uye dzimwe nguva nerubatsiro rwemvura inopisa.
3. Kugadziriswazve uye kugadzirwa kwezvicherwa zvitsva
Zvicherwa zvekare zvinova zvisina kugadzikana kana tembiricha itsva yavapo. Makristaro anogona kukura (recrystallization) kana kugadzira zvicherwa zvakasiyana kuburikidza nemakemikari. Semuenzaniso, ivhu nezvimwe zvicherwa zvakapfava mumatombo e sedimentary zvinogona kushanduka kuita zvicherwa zvakagadzikana.
4. Kuumbwa kwe metamorphic aureole
Nzvimbo inokanganiswa nekupisa yakakomberedza kupinda kwechinhu inonzi metamorphic aureole. Aureole iyi inowanzo ratidza nzvimbo dzekuchinja: pedyo nekupindira kwechinhu, mwero wekuchinja kwechinhu wakakwira, wobva waderera sezvaunofamba.
5. Kutonhodza uye "kuomesa" zvigadzirwa zvemetamorphic
Kana kupinda kwemvura kwatonhora, mamiriro ekunze anodzikira uye kuchinja kwemaminerari kunomira. Dombo rakazobuda rino "vharirwa" sechinyorwa che geology chekupindira kwemvura.
Hunhu hwe contact metamorphism
Zvimwe zvinhu zvakajairika zvinowanikwa mu contact metamorphism:
– Nzvimbo yakapoteredza kupinda kwemvura: maitiro ekupararira kwemvura anotevera muviri wekupinda kwemvura, zvichiita kuti pave nechinhu chinonzi aureole.
– Inotongwa nekupisa kwakanyanya: kumanikidzwa hakuna kunaka sekuchinja kwenzvimbo.
– Magadzirirwo acho haawanzo kuva nemashizha: anogadzira matombo akawanda makuru akadai sehornfels kana marble.
– Kuchinja kwezvicherwa pakupisa kwakanyanya: kuoneka kwemamwe maminerari anoratidza kuwedzera kwekupisa.
– Kazhinji kacho kunobatanidzwa nekushanda kwemvura inopisa: mvura inopisa inogona kukurumidzisa maitiro uye kufambisa zvinhu zvemakemikari.
Matombo anokonzerwa nekuchinja kwemaonero (mienzaniso)
Heano mimwe mienzaniso yematombo anowanzo umbwa nekuda kwekuchinja kwechimiro chemuviri, pamwe chete nema protoliths awo uye hunhu hwawo.
1. Hornfels (dombo renyanga)
Hornfels idombo rinowanzo shandiswa pakubata matombo akafanana nematombo emhando ye "contact metamorphic", rinowanzo umbwa kubva mumatombo e "sedimentary" akadai se "shale" kana "siltstone". Nekuti rinodziya nekukurumidza uye harina simba rakawanda, hornfels dzine magadzirirwo akaomarara uye dzine zvicherwa zvakapfava. Dombo iri rinowanzo onekwa se "rakabikwa," uye mapfupa aro anogona kunge akapinza.
- Mapuroteni akajairika: shale, matombo emudhaka, matombo edota
- Hunhu: kusasviba, kutsvedzerera, kuomarara, ruvara runogona kuva rwakasviba
- Zvakatipoteredza: pedyo nekubatana kwe magma nekupinda
Hornfels dzinowanzova humbowo hwakasimba hwekuti nzvimbo iyi yakasangana nekupisa kwakanyanya kubva mukupindira.
2. Matombo
Matombo anoumbwa kubva mukusiyana kwematombo emestone kana dolostone. Pakupisa kwakanyanya, calcium kana dolomite minerals iri mumatombo emestone inozopedzisira yava makristaro makuru, akabatana. Nekuda kweizvozvo, matombo anowanzova nechitarisiko chekristaro uye anogona kukweshwa zvakanaka.
- Mapurotolith akajairika: limestone, dolostone
– Hunhu: isina foliated, crystalline, inopindura neacid (ye calcite marble)
- Kushandiswa: zvinhu zvekuvaka, zvifananidzo, zvishongo
Muma "contact metamorphic aureole" akatenderedza kupinda kwematombo, limestone inogona kushanduka kuita marble nekukurumidza.
3. Quartzite
Quartzite inoumbwa kubva mujecha re quartz. Kupisa kunoita kuti tsanga dze quartz dzibatane zvakasimba uye dziitezve crystal, zvichiita kuti dombo riome zvikuru. Mu quartzite, miganhu iri pakati petsanga inowanzo "nyangarika" sezvo fuse yemakristaro matsva.
- Protolith yakajairika: dombo rejecha re quartz
- Hunhu: hwakaoma kwazvo, husina foliation, hune quartz dominant
- Mashandisirwo: aggregate, matombo ekuvaka, mamwe matombo ekushongedza
Quartzite inobatana inowanzoonekwa kana chinhu chinopinda chichipisa quartz sandstone unit iri pedyo.
4. Skarn (muenzaniso wekuchinja kwekubatana kwemvura)
MaSkarns mienzaniso yakakosha nekuti anoratidza kuchinja kwakasimba kwekubatana kunotungamirirwa nemvura, kunyanya kana magma intrusions ichisangana nematombo ecarbonate (limestone/dolomite). Mvura inopisa ine silica nesimbi inogona kukonzera metasomatic reactions, ichigadzira zvicherwa zvakaita segarnet, pyroxene, uye wollastonite, zvinowanzobatanidzwa nezvicherwa zveore.
- General protolith: dombo recarbonate + simba rekupinda kwemagma
– Hunhu: zvicherwa zve calc-silicate (garnet/pyroxene), zvinowanzobatanidzwa ne minerals dze ore
- Kukosha kwehupfumi: kunogona kuva neCu, Fe, W, Zn, Pb, nezvimwewo.
Skarn inowanzo tsvakwa nevanoongorora nekuda kwekugona kwayo kutakura zvicherwa zvehupfumi.
5. Matombo ane calcium silicate
Kana matombo e sedimentary aine musanganiswa we carbonate nevhu/quartz, contact metamorphism inogona kugadzira matombo e calc-silicate ane zvicherwa zvakaita se diopside, epidote, tremolite, kana vesuvianite. Mhando idzi dzinowanzoonekwa muma aureoles akatenderedza kupinda mukati me sedimentary layers ane maumbirwo akasiyana.
- Protolith: sediment yakasanganiswa yecarbonate ne silicate
– Hunhu: hwakapfuma mu calcium silicate minerals, ruvara rwayo rwakasvibirira kusvika kubrown
- Mamiriro acho ezvinhu: nzvimbo iri pedyo nekupindirwa, kazhinji iri pedyo nematombo ematombo kana matombo ematombo
Mienzaniso yenzvimbo dze geological dzinosangana nevanhu
Kuchinja kwekubatana kunogona kuitika munzvimbo dzakasiyana-siyana dze tectonic, asi kunonyanya kuwanikwa mu:
– Matunhu emakomo anoputika uye nzvimbo dzinoita kuti makomo apinde: magma akawanda anokwira uye anooma mugomba.
– Nzvimbo yePlutonic: nzvimbo ine matombo anopisa akadai segranite.
– Nzvimbo dzakadzika dzekupinda: madhibhi nemasill zvinopisa matombo ari pedyo nepakati padiki.
Mumunda uyu, nyanzvi dzezve geology dzinowanzo ziva kuti contact metamorphism inoonekwa nekuchinja kwerudzi rwematombo akakomberedza kupindira. Semuenzaniso, kubva ku shale kure nekupindira kusvika ku hornfels dziri pedyo nekupindira; kana limestone kusvika ku marble munzvimbo yekubatana.
Kuenzanisa nekukurumidza: contact metamorphism vs regional metamorphism
Kuti urege kuvhiringidzika, heino misiyano mipfupi:
– Kuchinja kwekubatana: kupisa kwakanyanya, kuri munzvimbo dzakatenderedza kupinda kweganda, kusabatanidzwa kwemashizha, kugadzira ma "aureole".
– Kuchinja kwenzvimbo: kuchikonzerwa nekupisa + kumanikidzwa kwakanyanya munzvimbo yakakura (semuenzaniso, makomo ane njodzi), maruva akawandisa (schist, gneiss), mwero wekuchinja kwenzvimbo unosiyana zvichienderana nedunhu.
Penutup
Kuchinja kwematombo (contact metamorphism) inzira yekuchinja kwematombo inoitika nekuda kwekupisa kwakanyanya kutenderedza magma intrusion. Nekuti inotongwa nekupisa kwakanyanya uye inowanikwa munzvimbo imwe chete, kuchinja uku kunogadzira matombo asingawanzo svibi uye anoumba metamorphic aureole yakatenderedza intrusion. Mienzaniso yematombo anowanzo umbwa anosanganisira hornfels, marble, quartzite, uye mamwe marudzi akaomarara akadai se skarn ne calc-silicate rocks. Kunze kwekukosha pakunzwisisa nhoroondo ye geological yenzvimbo, kuchinja kwematombo (contact metamorphism) kunewo kukosha, kunyanya kana zvasvika pakuumbwa kwezvicherwa zvinokosha muhupfumi, zvakaita sezviri muma skarn systems.
Kana muchida, ndinogonawo kuwedzera mufananidzo we metamorphic aureole (nzvimbo dziri pedyo nekupinda kusvika kure), kana kugadzira shanduro yechinyorwa chino inotarisa zvakanyanya pamienzaniso yeIndonesia.
