Basaltiset

Basaltiset is a term used in geology to describe a class of mafic igneous rocks that share a basaltic bulk composition and typically fine-grained to aphanitic textures. The basaltiset group is characterized by low silica content and high concentrations of iron and magnesium, with primary minerals including plagioclase feldspar, pyroxene, and often olivine. Accessory minerals such as magnetite, ilmenite, and occasionally amphibole may occur.

Basaltiset rocks form from mafic magmas that crystallize rapidly at or near the Earth's surface. They are commonly produced at mid-ocean ridges, ocean islands, and continental rift zones, where upwelling mantle melts and differentiates to produce basaltic eruptions. Vesicular and porphyritic variants are common, reflecting differing cooling histories and gas content.

Geographically, basaltiset rocks are widespread in oceanic crust and in flood basalt provinces on continents. They can occur as lava flows, volcanic tuffs, or as intrusive bodies in which magma crystallized at shallow depths.

Uses of basaltiset rocks include construction aggregate, road base material, and dimension stone, reflecting their hardness and abundance. Weathering of basaltiset rocks contributes to fertile soils in certain climates, producing mineral-rich basalt-derived soils.

Etymology: the name derives from basalt with the -ite suffix used for rock names. In geology, Basaltiset is a semantic category used to discuss rocks with basaltic chemistry without committing to a strict mineralogical end-member.

See also: Basalt, Mafic rock, Oceanic crust, Flood basalt.