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The tholeiitic magma series (/ ˌ θ oʊ l i ˈ aɪ 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. Rock types of the ...
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 ...
In the Canary Islands, igneous rocks of the alkaline magma series are common, while rocks of the sub-alkaline tholeiitic magma series are rare. [25] Volcanic rock types found on the Canary Islands are typical of oceanic islands.
Most of the rock originated from tholeiitic magma series, formed from the shallow melting of the mantle and are very similar to the Mid-Ocean Ridge Basalt, although much thicker more akin to an oceanic plateau.
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 ...
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 OJP basaltic basement is four tholeiitic magma series called the Kwaimbaita, Kroenke, Singgalo, and Wairahito. [8] All except the Singgalo are isotopically identical so they are likely from the same mantle source. [8] It can be assumed that the Singgalo basalts have a different mantle source to the rest.
The alkaline series – subgroups of alkaline basalts and the rare, very high potassium-bearing (i.e. shoshonitic) lavas. This volcanic series is related to the age of the subduction zone and the depth. The tholeiitic magma series is well represented above young subduction zones formed by magma from relative shallow depth.