andmesideliinide

Andmesideliinide, also known as andesidelytes, are a class of volcanic rocks primarily composed of andesine, a plagioclase feldspar. They are typically intermediate in composition, falling between basalt and rhyolite. This means they have a moderate silica content, usually between 52% and 63%. Their texture can vary, but they are often porphyritic, containing larger crystals of andesine embedded in a finer-grained groundmass. Other common minerals found in andesideliinides include amphibole, pyroxene, and sometimes biotite.

These rocks are commonly found in volcanic arc settings, such as along convergent plate boundaries where oceanic crust subducts beneath continental or other oceanic crust. They are characteristic of stratovolcanoes and can be erupted in various forms, including lava flows, ash falls, and pyroclastic deposits. The formation of andesideliinides is generally attributed to fractional crystallization of basaltic magma, where certain minerals crystallize and are removed, leaving a more silica-rich melt. Alternatively, they can form through the partial melting of continental crust or by the mixing of basaltic and rhyolitic magmas. Their presence is often indicative of significant volcanic activity and tectonic processes.