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The calc-alkaline magma series is one of two main subdivisions of the subalkaline magma series, the other subalkaline magma series being the tholeiitic series. A magma series is a series of compositions that describes the evolution of a mafic magma, which is high in magnesium and iron and produces basalt or gabbro, as it fractionally crystallizes to become a felsic magma, which is low in ...
Rocks in the alkaline magma series are distinguished from rocks in the subalkaline tholeiitic and calc-alkaline magma series by their high content of alkali metal oxides (K 2 O plus Na 2 O) relative to silica (SiO 2). They are distinct from the rare peralkaline magmas, which have excess alkali oxides relative to alumina (Na 2 O + K 2 O > Al 2 O 3).
The tholeiitic magma series (/ ˌ θ oʊ l eɪ ˈ ɪ t ɪ k /) is one of two main magma series in subalkaline igneous rocks, the other being the calc-alkaline series. A magma series is a chemically distinct range of magma compositions that describes the evolution of a mafic magma into a more evolved, silica rich end member.
Volcanic arcs are characterized by explosive eruption of calc-alkaline magma, though young arcs sometimes erupt tholeiitic magma [7] and a few arcs erupt alkaline magma. [8] Calc-alkaline magma can be distinguished from tholeiitic magma, typical of mid-ocean ridges, by its higher aluminium and lower iron content [9]: 143–146 and by its high ...
English: The AFM diagram, a ternary diagram between the Alkali, Fe, and Mg oxides used to distinguish the calc-alkaline magma series from the tholeiitic magma series. Key/Legend: A–alkali (sodium and potassium) oxides, F–iron oxides, M–magnesium oxide, BT–tholeiitic basalt, FB–ferro-basalt, ABT–tholeiitic basaltic andesite, AT–tholeiitic andesite, D–dacite, R–rhyolite, B ...
In this chamber an underplating process will take place, the assimilation and fractional crystallization of primary magma and lower crustal rocks forms underplate at the bottom of crust. [4] [5] Through those procedure the olivine tholeiitic primary magma would change to calc-alkaline magmas and more evolved and enriched alkaline or siliceous ...
Iron oxide lavas are thought to be the result of immiscible separation of iron oxide magma from a parental magma of calc-alkaline or alkaline composition. [17] When erupted, the temperature of the molten iron oxide magma is about 700 to 800 °C (1,292 to 1,472 °F).
The magmatism is mostly calc-alkaline in type along a well-defined curvilinear magmatic arc. Only the volcanic parts of modern arcs are exposed at the surface and the understanding of the underlying magma chambers relies on geophysical methods. Ancient arc sequences that formed on continental crust or that have become accreted to continental ...