Nefelinite

Nefelinite is a rare, dark-colored, silica-undersaturated extrusive igneous rock, typically occurring in volcanic lava flows, dikes, and sometimes as small intrusive bodies. It is composed primarily of nepheline and pyroxene, with minor amounts of other minerals like olivine and melilite. nefelinite is classified within the foidite group due to its high concentration of feldspathoids (nepheline being the key one) and its low silica content, distinguishing it from more common silica-saturated rocks like basalt. The specific mineral assemblage and texture provide valuable insights into the magma's composition and cooling history, helping geologists understand the formation processes in specific volcanic environments. Its scarcity and unique composition make nefelinite a subject of interest for petrologists and volcanologists.

Nefelinite meaning with examples

• The geological survey team identified a small outcropping of nefelinite on the remote island, excited by the potential clues it could offer about the underlying mantle plume activity. Analysis of the nefelinite's chemical composition, including trace elements, gave valuable information about the magma source depths and source materials.
• The lava flow at the base of the volcano, determined through mineral identification and laboratory testing to be nefelinite, posed a unique hazard to the local population. The discovery, coupled with a detailed assessment of the flow rate and its chemical makeup, allowed for the implementation of an early warning system.
• Geologists studying the alkaline volcanic province in the region used the presence and distribution of nefelinite to map out past eruption patterns. These findings improved understanding of the region's long-term volcanic history, which helped with predicting future volcanic events. They analyzed the associated minerals to aid in their findings.
• The petrography of the collected samples from the mine showed that the unusual rock type, previously overlooked, was nefelinite. It contained specific inclusion patterns that revealed the magma’s crystallization process, enabling a better understanding of the magmatic evolution of the region.