Incipient carbonate melting drives metal and sulfur mobilization in the mantle

Abstract

Abstract We present results from high-pressure, high-temperature experiments that generate incipient carbonate melts at mantle conditions (~ 90 km depth and temperatures between 900–1050°C). We show that these primitive carbonate melts can sequester sulfur in its oxidized form of sulfate, as well as base and precious metals from mantle lithologies of peridotite and pyroxenite. It is proposed that these carbonate-sulfur-rich melts may be more widespread than previously thought, and that they may play a first order role in the metallogenic enhancement of localized lithospheric domains. They act as effective agents to dissolve, redistribute and concentrate metals within discrete domains of the mantle and into shallower regions within the Earth, where dynamic physico-chemical processes can lead to ore genesis at various crustal depths. Green metals could be transported and concentrated into ores by their interaction with low temperature carbonate rich melts.