experimental petrology; deep Earth; lower mantle; Fe(II)-disproportionation; redox equilibria; carbonatite melting; banded iron formation; geochemical mantle anomalies; recycling; transition zone; Deep Carbon recycling; Earth mantle; Diamond formation; Redox reactions; Archean banded iron formation
Rosa Angelika, Sanchez-Valle Carmen, Ghosh Sujoy, Elasticity of phase D and implication for the degree of hydration of deep subducted slabs., in Geophys.Res.Lett.
, 39(na), na-na.
Grassi Daniele, Schmidt Max W., Günther Detlef, Element partitioning during pelite melting at 8, 13, and 22 GPa and the sediment signature in the EM mantle component., in Earth Planet. Sci. Lett.
, 327-328, 84-96.
Grassi Daniele, Schmidt Max W., Melting of carbonated pelites at 8-13 GPa: generating K-rich carbonatites for mantle metasomatism, in Contrib. Min. Petrol.
, 162, 169-181.
Rohrbach Arno, Schmidt Max W., Redox freezing and melting in the Earth’s deep mantle resulting from carbon-iron redox coupling., in Nature
, 472, 209-212.
Sanchez-Valle Carmen, Ghosh Sujoy, Rosa Angelika, Sound velocities of ferromagnesian carbonates and the seismic detection of carbonates in eclogites and the mantle, in Geophys.Res.Lett.
, 38(na), na-na.
Grassi Daniele, Schmidt Max W., The melting of carbonated pelites from 70 to 700 km depth, in J. Petrol.
, 52, 765-789.
The dynamics of the Earth is intimately related to magmas and fluids which transfer elements from one geochemical reservoir to the other, and which are responsible for large scale geochemical cycles. At depth > 200 km, Fe and C bearing redox and melting equilibria are main drivers in deep melt generation. Three projects are grouped along this main theme: (i) Redox equilibria and carbonatite melting which involve the disproportionation of ferrous to ferric+metallic iron in the deep mantle, the influence of water on these equilibria, and the H-storage capacity of mantle minerals at realistic oxygen fugacities will all serve to understand the origin of melting in the transition zone and lower mantle. (ii) We will investigate the subduction of ancient, oxidized, extremely dense sediments, the banded iron formations (BIF), which are mainly composed of Fe-oxides and -carbonates and quartz and which are in great disequilibrium with the reduced mantle. This, in order to understand to what extent BIFs are assimilated into the mantle, what geochemical mantle signature can be derived, and whether BIFs may descend to the core-mantle boundary. (iii) We will investigate the infiltration of oxidized pelitic sediment derived carbonatites into the reduced mantle and the generation of K- and C-rich mantle domains, which may ultimately give rise to kimberlites and diamonds. In these projects, experiments between 3 and 40 GPa will allow to define the reactions and geochemical transfers involved in these processes and give rise to appropriate quantitative models for improving our picture of the dynamic deep Earth.