Generasidan AfinitasMagmaAKHMAD ZAMRONI

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Apakah di setiap hot spot ada gunung api

dan di setiap gunung api ada hot spot?

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Afinitas tektonik seri batuan gunungapi

Didasarkan atas Kandungan SiO2 dalam magma, tipe /kelompok batuan GUNUNGAPI DAN KETERDAPatannyaterhadap tatanan tektoniknya adalah:

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Magma Alkaline dan Magma Subalkaline

The difference between the Alkaline series and Subalkaline series is that the Alkaline rocks are

richer in alkalis and are commonly silica under saturated while the Subalkaline rocks are silica

saturated to oversaturated. They are distinguished in a total alkali versus silica diagram.

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Alkaline rocks

Alkaline rock, any of various rocks in which the chemical content of the alkalies (potassium oxide

and sodium oxide) is great enough for alkaline minerals to form. Such minerals may be unusually

sodium rich, with a relatively high ratio of alkalies to silica (SiO2), as in the feldspathoids. Other

alkaline minerals have a high ratio of alkalies to alumina (Al2O3), as in aegirine pyroxene and the

sodic amphibole riebeckite.

English-speaking petrologists have followed Alfred Harker, who divided igneous rocks of Cenozoic

age (that is, those laid down between about 65.5 million years ago and the present day) into calc-

alkaline and alkaline suites. Alkaline rocks include many with unusual names, but the more

common alkali-basalt, syenite, and phonolite are included in the group

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Kelompok Magma Subalkaline

Terdiri dari kelompok magma kalk-alkali dan toleitik. Kelompok magma adalah kelompok komposisiyang menggambarkan evolusi magma mafik, yang tinggi akan magnesium dan besi sertamemproduksi basal atau gabro, hingga mengalami kristalisasi fraksional menjadi magma felsik yang rendah akan magnesium dan besi serta memproduksi riolit atau granit. Batuan kalk-alkali kaya akan alkali tanah (magnesia dan kalsium oksida) serta alkali metal yang mendominasi kerak-kerakbenua.

Batuan dari kelompok magma kalk-alkalin dibedakan dengan kelompok magma toleitik oleh keadaan redoks magma asal kristalnya ( magma toleitik reduksi, dan magma kalk-alkalin oksidasi). Ketika magma mafik (magma yistalisasi, mereka memiilih mengkristal menjadi mineral silikat yang kaya magnesium dan miskin besi seperti olivin dan piroksen, menyebabkan kandungan besi magma toleitik meningkat ketika pencairan dihilangkan dari kristal-kristal miskin besi.

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The Classification of

Igneous Rocks Into Suites

Igneous rocks are classified

on several different criteria,

including color, mineral composition, and chemistry.

The classification based on

igneous suites is a chemical

classification. There are four

major suites summarized in the table below.

The Classification of Igneous

Rocks Into Suites

Igneous rocks are classified

on several different criteria,

including color, mineral

composition, and chemistry.

The classification based on

igneous suites is a chemical

classification.