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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 are characteristic of continental rifting, areas overlying deeply subducted plates, or at intraplate hotspots. [2]: Ch6 They are more likely to be generated at greater depths in the mantle than subalkaline magmas. [2]: Ch23.6. Alkaline rocks are rare in the Archean, but become common in the Proterozoic.
Dacite (/ ˈdeɪsaɪt /) is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. It is composed predominantly of plagioclase feldspar and quartz.
The tholeiitic magma series (/ ˌθoʊliˈaɪtɪk /) 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 tholeiitic ...
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 ...
Magmatism. Geological map showing the Gangdese batholith, which is a product of magmatic activity about 100 million years ago. Magmatism is the emplacement of magma within and at the surface of the outer layers of a terrestrial planet, which solidifies as igneous rocks. It does so through magmatic activity or igneous activity, the production ...
Porphyry copper deposits represent an important resource and the dominant source of copper that is mined today to satisfy global demand. [6] Via compilation of geological data, it has been found that the majority of porphyry deposits are Phanerozoic in age and were emplaced at depths of approximately 1 to 6 kilometres with vertical thicknesses on average of 2 kilometres. [6]
The tholeiitic magma series is well represented above young subduction zones formed by magma from relative shallow depth. The calc-alkaline and alkaline series are seen in mature subduction zones, and are related to magma of greater depths. Andesite and basaltic andesite are the most abundant volcanic rock in island arc which is indicative of ...