Melting of MORB at core-mantle boundary

作者：Pradhan Gopal K^*; Fiquet Guillaume; Siebert Julien; Auzende Anne Line; Morard Guillaume; Antonangeli Daniele; Garbarino Gaston

来源：Earth and Planetary Science Letters, 2015, 431: 247-255.

DOI：10.1016/j.epsl.2015.09.034

• core-mantle boundary
• ULVZ
• partial melting
• experimental mineralogy
• high-pressure melting
• laser heating

We investigated the melting properties of natural mid-ocean ridge basalt (MORB) up to core-mantle boundary (CMB) pressures using laser-heated diamond anvil cell. Textural and chemical characterizations of quenched samples were performed by analytical transmission electron microscopy. We used in situ X-ray diffraction primarily for phase identification whereas our melting criterion based on laser power versus temperature plateau combined with textural analysis of recovered solidus and subsolidus samples is accurate and unambiguous. At CMB pressure (135 GPa), the MORB solidus temperature is 3970 (+/- 150) K. Quenched melt textures observed in recovered samples indicate that CaSiO3 perovskite (CaPv) is the liquidus phase in the entire pressure range up to CMB. The partial melt composition derived from the central melt pool is enriched in FeO, which suggests that such melt pockets may be gravitationally stable at the core mantle boundary.

• 出版日期2015-12-1