Flotation of Diamond in Mantle Melt at High Pressure

See allHide authors and affiliations

Science  14 Jul 1995:
Vol. 269, Issue 5221, pp. 216-218
DOI: 10.1126/science.269.5221.216


Experiments show that diamond floats in a primitive mantle melt at around 20 gigapascals and 2360°C and in a melt formed by partial melting of the transition zone at about 16 gigapascals and 2270°C. These observations constrain magma densities at high pressure. Diamond precipitated or trapped in a silicate melt at the base of the transition zone or the lower mantle floats and has been accumulating in the transition zone since early in Earth's history. Thus, the transition zone could be a reservoir of diamond.