Boninite is an extrusive rock high in both magnesium and silica, thought to be usually formed in fore-arc environments, typically during the early stages of subduction. The rock is named for its occurrence in the Izu-Bonin arc south of Japan. It is characterized by extreme depletion in incompatible trace elements that are not fluid mobile (e.g., the heavy rare-earth elements plus Nb, Ta, Hf) but variable enrichment in the fluid mobile elements (e.g., Rb, Ba, K). They are found almost exclusively in the fore-arc of primitive island arcs (that is, closer to the ocean trench) and in ophiolite com
Boninite is an extrusive rock high in both magnesium and silica, thought to be usually formed in fore-arc environments, typically during the early stages of subduction. The rock is named for its occurrence in the Izu-Bonin arc south of Japan. It is characterized by extreme depletion in incompatible trace elements that are not fluid mobile (e.g., the heavy rare-earth elements plus Nb, Ta, Hf) but variable enrichment in the fluid mobile elements (e.g., Rb, Ba, K). They are found almost exclusively in the fore-arc of primitive island arcs (that is, closer to the ocean trench) and in ophiolite complexes thought to represent former fore-arc settings or at least formed above a subduction zone.
Boninite is considered to be a primitive andesite derived from melting of metasomatised mantle.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).