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The andesite line is the most significant regional geologic distinction in the Pacific Ocean basin. It separates the mafic basaltic volcanic rocks of the Central Pacific Basin from the partially submerged continental areas of more felsic andesitic volcanic rock on its margins.
Andesite (/ ˈ æ n d ə z aɪ t /) [1] is a volcanic rock of intermediate composition.In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite.
For example, andesitic magmatism is associated with the formation of island arcs at convergent plate boundaries while basaltic magmatism is found at mid-ocean ridges during sea-floor spreading at divergent plate boundaries. On Earth, magma forms by partial melting of silicate rocks either in the mantle, continental or oceanic crust. Evidence ...
Andesitic magma is an intermediate magma and is approximately evenly dispersed regarding iron, magnesium, calcium, sodium, and potassium. [1] [3] The silica composition of andesitic magma ranges from 55 - 65 wt.%. [1] It forms in temperatures ranging from approximately 1470 °F to 1830 °F.
A continental arc is a type of volcanic arc occurring as an "arc-shape" topographic high region along a continental margin.The continental arc is formed at an active continental margin where two tectonic plates meet, and where one plate has continental crust and the other oceanic crust along the line of plate convergence, and a subduction zone develops.
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.
The composition of the soil found on Vikram’s landing site is consistent with an ancient magma ocean, the authors conclude. When analyzing the soil, the researchers found a relatively uniform ...
Arcs produce about 10% of the total volume of magma produced each year on Earth (approximately 0.75 cubic kilometers), much less than the volume produced at mid-ocean ridges, [67] but they have formed most continental crust. [4] Arc volcanism has the greatest impact on humans because many arc volcanoes lie above sea level and erupt violently.