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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.
The individual crystals in an aphanitic igneous rock are not distinguishable to the naked eye. Examples of aphanitic igneous rock include basalt, andesite, and rhyolite. Glassy or vitreous textures occur during some volcanic eruptions when the lava is quenched so rapidly that crystallization cannot occur. The result is a natural amorphous glass ...
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.
Basaltic andesite from Parícutin volcano in Mexico. Basaltic andesite is a volcanic rock that is intermediate in composition between basalt and andesite. It is composed predominantly of augite and plagioclase. Basaltic andesite can be found in volcanoes around the world, including in Central America [1] and the Andes of South America. [2]
The Ica stones are engraved with various types of images. ... Cabrera stated that andesite is a hard stone that is difficult to carve, particularly using stone tools ...
AFM diagram showing the relative proportions of the oxides of alkalis (A), iron (F), and magnesium (M), with arrows showing the compositional change path of the magmas in the tholeiitic and the calc-alkaline magma series (BT=tholeiitic basalt, FB=ferro-basalt, ABT=tholeiitic basaltic andesite, AT=tholeiitic andesite, D=dacite, R=rhyolite, B=basalt, AB=basaltic andesite, A=andesite; dashed line ...
The composition data indicate that Ollagüe was underpinned by a large magma chamber that was the source of the main edifice building andesite magmas. [81] In this main magma chamber, differentiation processes generated the andesitic and dacitic magmas from basaltic andesite. The chamber itself was chemically zoned. [82]
The Bearwallow Mountain Andesite is composed of calc-alkaline volcanic rock ranging from basaltic andesite to dacite, but predominantly andesite.These form a group of low cones or shield volcanoes and range in age from 27 to 23 million years old.