Petrological Database of the Ocean Floor

The Petrological Database of the Ocean Floor (PetDB) is a relational database for global geochemical data on igneous and metamorphic rocks generated at mid-ocean ridges including back-arc basins, young seamounts, and old oceanic crust, as well as ophiolites and terrestrial xenoliths from the mantle and lower crust and diamond geochemistry. These data are obtained by analyses of whole rock powders, volcanic glasses, and minerals by a wide range of techniques including mass spectrometry, atomic emission spectrometry, x-ray fluorescence spectrometry, and wet chemical analyses.

Source: Wikipedia — Petrological Database of the Ocean Floor (CC BY-SA 4.0)