Mefuta ea Majoe a Igneous ho ea ka Diminerale tse Lekaneng
Mafika a igneous ke mafika a bopilweng ke ho phodisa le ho etsa magma kapa lava hore e be kristale. Ts'ebetso ena e ka etsahala ka tlase ho bokaholimo ba Lefatše (ho kenella/ho bokellana) kapa holim'a bokaholimo ba Lefatše (ho ntša/ho foqoha ha seretse se chesang). Le hoja mafika a igneous a atisa ho khetholloa ka sebaka seo a bōpehileng kapa sebopeho sa 'ona, e 'ngoe ea mekhoa ea bohlokoa ka ho fetisisa ea ho arola jeoloji e ipapisitse le litaba tsa bona tsa diminerale—haholo-holo karolo ea liminerale tsa silicate tse kang quartz le feldspar, hammoho le liminerale tse mafic tse kang pyroxene le olivine. Liminerale tsena li amana haufi-ufi le metsoako ea lik'hemik'hale (mohlala, litaba tsa silica/SiO₂) 'me qetellong li khetholla' mala, bongata le boitšoaro ba lefika ha le tiea.
Ka kakaretso, mafika a igneous a ka aroloa ka mefuta e mengata e meholo ho latela diminerale tsa ona: felsic, intermediate, mafic, le ultramafic. Ho phaella moo, ho boetse ho na le dihlopha tse ikgethang, tse kang mafika a igneous a alkaline, a kgethololwang ka diminerale tse itseng (mohlala, feldspathoids). Ka tlase ke tlhaloso ya mofuta o mong le o mong le dibopeho tsa wona tsa minerale.
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1) Lefika la Felsic Igneous (le ruileng ka silica le diminerale tse bobebe)
Lentsoe felsic le tsoa motsoakong oa mantsoe feldspar le silica. Majoe a felsic igneous ka kakaretso a na le silica e ngata (hoo e ka bang > 65% SiO₂) 'me a laoloa ke liminerale tse mebala e khanyang. Ho ea ka diminerale, mafika ana hangata a na le:
– Quartz: minerale e tloaelehileng haholo ea silicate mafikeng a felsic.
– Alkali feldspar (orthoclase/microcline) le plagioclase e nang le sodium e ngata (albite–oligoclase).
– Mica (muscovite, biotite) e le diminerale tse thusang.
– Ka nako e 'ngoe e na le bongata bo bonyenyane ba amphibole.
Ka mahlo, mafika a felsic a atisa ho ba le 'mala o bobebe (o mosweu, tranelate, kapa o moputsoa o bobebe) ka lebaka la ho busa ha quartz le feldspar. Felsic magma hangata e na le viscous haholoanyane, e e lumellang ho tšoasa khase, 'me e amahanngoa le ho phatloha ho phatlohang ha mofuta oa extrusive.
Mehlala ea mafika a felsic:
– Granite (e kenellang): lithollo tsa diminerale li mahoashe, quartz le feldspar li bonahala ka ho hlaka.
– Rhiolite (extrusive): motsoako o tšoanang le granite, empa o boreleli hobane o phola kapele.
– Dacite (felsic–e mahareng): hangata e na le plagioclase le quartz.
Boteng ba quartz ke letšoao la bohlokoa: ha quartz e le ngata, lefika hangata le oela sehlopheng sa felsic (kapa bonyane intermediate-felsic), ho latela karolo ea liminerale tse mafic.
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2) Lefika le Mahareng la Igneous (motsoako o mahareng, diminerale tse tswakilweng)
Majoe a igneous a mahareng a oela pakeng tsa felsic le mafic. Ka kakaretso silika ea bona e ka ba 52–65% SiO₂. Ho latela diminerale, majwe ana a khetholloa ka:
– Plagioclase (ka kakaretso andesine) e le minerale e ka sehloohong.
– Amphibole (hornblende) le/kapa pyroxene e le diminerale tse ka sehloohong tse lefifi.
– Biotite e ka ’na ea ba teng.
– Quartz e ka ’na ea e-ba teng, empa hangata ha e eo haholo joaloka mafikeng a felsic.
Mafika a mahareng hangata a na le 'mala o moputsoa o mahareng: ha a bobebe joaloka granite, empa ha a lefifi joaloka basalt. Magma ea bona e na le viscosity e mahareng 'me hangata e amahanngoa le li-arcs tsa seretse se chesang ( libaka tse ka tlase ho volkano ), kahoo mafika a mahareng a atile haholo libakeng tsa seretse se chesang se mafolofolo.
Mehlala ea mafika a mahareng:
– Diorite (e kenellang): plagioclase le amphibole li hlaha ka likristale tse kholo haholo.
– Andesite (extrusive): e atile haholo e le lefika la seretse se chesang; e putsoa ka 'mala 'me hangata e na le sebopeho se kang sa porphyritic (phenocrysts e teng mobung o mosesaane).
Phapang ea bohlokoa ka felsics hangata ke quartz e fokolang le liminerale tse ngata tsa mafic (amphiboles/pyroxenes).
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3) Lefika la Mafic Igneous (le nang le tšepe e ngata le magnesium, le nang le diminerale tse lefifi)
Mafika a Mafic a entsoe ka magnesium le tšepe. Mafika a Mafic a nang le silika a na le silika e tlase (hoo e ka bang 45–52% SiO₂) mme a laoloa ke liminerale tse nang le Fe-Mg e ngata. Ho ea ka diminerale, mafika a mafic hangata a na le:
– Pyroxene (augite) e le minerale e ka sehloohong.
– Plagioclase e nang le calcium e ngata (labradorite–bytownite).
– Olivine e ka ba teng, ka linako tse ling ka bongata bo boholo.
– Liminerale tse sa bonahaleng tse kang magnetite le ilmenite hangata li hlaha e le lisebelisoa.
Kaha diminerale tse ngata tsa mafic di na le mmala o lefifi, majwe ana hangata a matsho kapa a matala a lefifi, a teteaneng ho feta felsic, mme magma ya ona e metsi haholo (ho ba le viscosity e tlase). Mafic lava e atisa ho phalla hole mme hangata e hlahisa phallo e kgolo ya lava.
Mehlala ea mafika a mafic:
– Gabbro (e kenellang): ka sebopeho e lekana le basalt, empa sebopeho se mahoashe.
– Basalt (extrusive): e atile haholo karolong e ka holimo ea leoatle; sebopeho se tšesaane ho isa ho se nang le vesicular (se tletseng khase).
– Diabase/Dolerite (hypabyssal): sebopeho se mahareng, hangata se tlatsa mapetsong jwalo ka di-dikes.
Tšobotsi e hlahelletseng ea mineralo ke ho ata ha calcic pyroxene-plagioclase, moo quartz e leng sieo ka kakaretso.
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4) Mafika a Ultramafic Igneous (a ruileng haholo ka diminerale tse makatsang, a na le silica e tlase haholo)
Majoe a Ultramafic ke sehlopha sa "mafic" ka ho fetisisa 'me hangata a na le silica e tlase haholo (ka kakaretso < 45% SiO₂). Sehlopha sena se laoloa ke liminerale tse latelang:
– Olivine ka bongata bo boholo.
– Pyroxene (ortho/clinopyroxene).
– Plagioclase e nyane haholo kapa ha e eo.
– Ka linako tse ling e na le liminerale tse kang spinel le garnet tlas'a maemo a itseng.
Majwe a Ultramafic hangata a lefifi haholo ho isa botala, a teteaneng haholo, mme hangata a amahanngoa le majwe a mantle. Hodima bokahodimo, majwe ana ha a fumanehe a le foreshe, hangata a fetoha serpentinite (tshebetso e bitswang serpentinization) ka lebaka la dikarabelo tsa metsi.
Mehlala ea mafika a ultramafic:
– Peridotite (e leng olivine haholo + pyroxene): lefika le ka sehloohong le etsang karolo e ka hodimo ya lefika.
– Dunite (e batlang e le olivine ka botlalo).
– Komatiite (e ntšang lintho tse ngata haholo, e atileng haholo mafikeng a khale haholo/a Archean).
Bongata ba olivine ke sesupo se seholo sa hore lefika le phahame haholo.
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5) Mafika a Alkaline Igneous le Karolo ea Feldspathoids (sehlopha se khethehileng sa mineralology)
Ntle le karohano ea felsic-intermediate-mafic-ultramafic, litsebi tsa jeoloji li boetse li lemoha majoe a alkaline igneous a khetholloang ka dikahare tse phahameng tsa alkali (Na₂O le K₂O). Litsamaisong tse ling, majoe a alkaline a khetholloa ka boteng ba liminerale tsa feldspathoid (mohlala, nepheline, leucite, sodalite) tse hlahang ha magma e haella silica, e leng se etsang hore quartz e se ke ea tsitsa.
Ho latela diminerale, majwe a alkaline a ka bontsha:
– Alkali feldspar e ngata.
– Feldspathoid e le sebaka sa quartz.
– Diminerale tse itseng tse makatsang tse kang aegirine kapa arfvedsonite ka mefuta e meng.
Mehlala ea majoe a alkaline:
– Syyenite (e ts'oanang le granite empa e na le quartz e nyane kapa ha e na quartz; alkali feldspar e atile).
– Nepheline syenite (e na le nepheline).
– Phonolite (e ntšang lintho tse ling, hangata e amahanngoa le nepheline/leucite).
Lihlopha tsa alkaline li bohlokoa hobane li bontša maemo a fapaneng a ho thehoa ha magma, hangata a amanang le libaka tse itseng tsa tectonic le phetoho e rarahaneng ea magma.
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Hobaneng ha Diminerale di le Bohlokwa ho Hlophiseng?
Diminerale tse teng mafikeng a igneous ha di hlalose feela "sebopeho", empa hape di thusa ho hlalosa:
1. Tšimoloho ea magma (mohlala, ho tsoa mantle kapa phello ea ho qhibiliha ha lekhapetla).
2. Maemo a ho etsa kristale (mocheso, khatello, metsi).
3. Tikoloho ea Tectonic (mabota a bohareng ba leoatle, li-arc tse ka tlase ho tekano, libaka tse chesang).
4. Thepa ea 'mele ea mafika ('mala, ho teteana, matla le bokhoni ba ho hloleha ha leholimo).
Mohlala, mafika a felsic a ruileng ka quartz le feldspar hangata a bopa ho tloha ho magmas e ntlafetseng (e "hōlileng" haholoanyane ka phapang), athe mafika a ultramafic a bonahatsa thepa e haufi le sebopeho sa mantle.
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Ho koala
Mefuta ea majoe a igneous ho latela diminerale tsa ona—lihlopha tsa felsic, intermediate, mafic, ultramafic, le alkaline—e fana ka moralo o hlakileng oa ho utloisisa mefuta-futa ea majoe a igneous Lefatšeng. Ka ho khetholla liminerale tse hlahelletseng tse kang quartz, feldspar, plagioclase, pyroxene, le olivine, re ka hakanya sebopeho sa silika ea tsona, 'mala, bongata, esita le lits'ebetso tsa jeoloji tse li entseng. Karohano ena ea mineralological e fana ka motheo oa bohlokoa bakeng sa lithuto tsa petrological, lipatlisiso tsa mehloli ea jeoloji, le kutloisiso ea phetoho ea bokaholimo ba Lefatše ha nako e ntse e ea.
Haeba o lakatsa, nka eketsa tafole e kgutshwane ya papiso (diminerale tse ka sehloohong, mebala, mehlala e kenellang-e ntshang) kapa ka bokella mofuta o tsebahalang haholo wa sengoloa bakeng sa mesebetsi ya sekolo.
