The geochemistry of peridotites provides constraints on the evolution of mantle composition; length-scales and sizes of heterogeneities in the mantle; melt migration at mid-ocean ridges; and melt-rock reaction processes at ridges and subduction zones.

Abyssal Peridotite, Southwest Indian Ridge

Photomicrographs of fresh and altered peridotites

Comparison of basalt and peridotite isotopic compositions (Warren et al., 2009):