Fig. 5: Whole-rock geochemistry of the IODP Sites U1614 and U1616 peridotites compared to peridotites from other geodynamic settings.
From: Heterogeneous Earth’s mantle drilled at an embryonic ocean
Covariations in Al2O3 versus (a) TiO2 and (b) K2O contents and comparison between (c) Al2O3 and (d) K2O contents between the Tyrrhenian Sea peridotites and abyssal peridotites from mid-ocean ridges (MOR)57,58, back-arc basin59, Continent-Ocean Transitions (COT) and fore-arc peridotites54. Compositions of orogenic peridotites and mantle xenoliths from the circum-Mediterranean area are compiled from the PetDB database (https://search.earthchem.org/). In (a), the compositions of abyssal peridotites are compared to the Al2O3 versus TiO2 compositions of mantle residues of fractional melting. Residual mantle compositions were thermodynamically calculated using pMELTS60 included in alphaMELTS software package61. Depleted-MORB Mantle (DMM) composition62 (K, P, and Cr were excluded) was chosen as source material. Isentropic near fractional melting of DMM was conducted at pressures ranging from 3 to 1 × 10-4 GPa at 1450 °C. The melting trend is depicted in pink, and values of melting degrees are in pink italic numbers (see values in Supplementary Data 4).
