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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 ...
Alkaline magmas tend to show high titanium oxide (TiO 2) content, typically in excess of 3% by weight. Other incompatible elements, such as phosphorus and light rare earth elements, are also elevated. This is attributed to a very low degree of partial melting of the source rock, with only 5% or less of the source rock going into the magma melt. [3]
Andesite and basaltic andesite are the most abundant volcanic rock in island arc which is indicative of the calc-alkaline magmas. Some island arcs have distributed volcanic series as can be seen in the Japanese island arc system where the volcanic rocks change from tholeiite—calc-alkaline—alkaline with increasing distance from the trench ...
Pages in category "Calc-alkaline rocks" The following 2 pages are in this category, out of 2 total. This list may not reflect recent changes. C.
Tholeiitic rock types tend to be more enriched in iron and less enriched in aluminium than calc-alkaline rock types. They are thought to form in a less oxidized environment than calc-alkaline rocks. Tholeiitic basalt is formed at mid-ocean ridges and makes up much of the oceanic crust. Almost all the basalt found on the Moon is tholeiitic basalt.
In the rock record, volcanic arcs can be recognized from their thick sequences of volcaniclastic rock (formed by explosive volcanism) interbedded with greywackes and mudstones and by their calc-alkaline composition. In more ancient rocks that have experienced metamorphism and alteration of their composition (metasomatism), calc-alkaline rocks ...
Carbonatite liquid compositions are significantly more alkaline than what is preserved in the fossil carbonatite rock record as composition of the melt inclusions shows. [4] Only one carbonatite volcano is known to have erupted in historical time, the active Ol Doinyo Lengai volcano in Tanzania. It erupts with the coolest lava in the world, at ...
Peralkaline volcanic rocks are defined as rocks having Na 2 O + K 2 O > Al 2 O 3, so that some of the alkali oxides must be present as aegirine or sodic amphibole rather than feldspar. [9] [8] The chemistry of volcanic rocks is dependent on two things: the initial composition of the primary magma and the subsequent differentiation.