What is the term for viscous magmas that are high in silica and tend to stay below the surface or erupt explosively?
combustible magmas
sedimentary magmas
compacted magmas
felsic magmas
The chemistry of a magma determines the type of igneous rock it forms. The chemistry also determines how the magma moves. The higher the amount of silica in the magma, the higher the viscosity. Viscosity is a liquid's resistance to flow. Viscous magmas tend to stay below the surface or erupt explosively. These are felsic magmas, which are high in silica. When magma is fluid and runny, it is not viscous. This magma often reaches the surface by flowing out in rivers of lava. These are low-silica mafic magmas.