Search results
Results from the WOW.Com Content Network
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).
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.
The volcano has erupted mainly calc-alkaline rocks ranging from basalt to rhyolite. Activity began in the Pleistocene. Aniakchak is one of the most active volcanoes in Alaska and underwent several significant caldera-forming eruptions. The largest eruption is known as Aniakchak II and took place in 1628/1627 BCE.
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 ...
The older rocks of the terrane rest in the Precambrian with younger Cambrian rocks resting unconformably upon them. The Precambrian rocks are noted to be calc-alkaline plutonic intrusions dated to approximately 700-600 Ma (Phase 1 to Phase 2 Neoproterozoic). These have associated (younger) volcanics that dominate the overlying sedimentary rocks ...
The rock is metaluminous, rich in sodium and belongs to the intrusive, mantle source-derived I-type granitoids. It is a typical calc-alkaline rock from the root zone of an ancient volcanic arc and associated with a subduction-type environment .