Litosferin

Litosferin is a proposed mineral phase in geoscience, described as a silicate-rich compound thought to form within the Earth's lithosphere under high-pressure metamorphic conditions. The term is used primarily in theoretical petrology to discuss possible constituents of the lower crust and upper mantle; it is not a confirmed mineral species.

According to models, litosferin would crystallize at pressures corresponding to depths of roughly 20 to 200 kilometers and would coexist with mantle-crust minerals such as olivine, pyroxenes, and garnet. Its proposed crystal structure is described as dense and layered, enabling strong seismic velocities associated with mantle rocks.

Predicted properties include high density, high melting point, and substantial elasticity; these features would influence interpretations of seismic data in lithospheric and subduction-zone contexts. If real, litosferin could act as a reservoir for certain trace elements and affect geochemical differentiation at the crust-mantle boundary.

Current evidence for litosferin is indirect. No unambiguous mineral specimen has been identified as litosferin; researchers rely on high-pressure experiments, thermodynamic modeling, and reinterpretations of seismic and petrological data. The term remains primarily theoretical and is used to test hypotheses about lithospheric composition and processes.

For related topics see lithosphere, mantle minerals, high-pressure metamorphism, and geochemical reservoirs.