https://www.usgs.gov/publications/composition-earths-upper-mantle-i-siderophile-trace-elements-ultramafic-nodules
Seven siderophile elements (Au, Ge, Ir, Ni, Pd, Os, Re) were determined by radiochemical neutron activation analysis in 19 ultramafic rocks, which are spinel...
the earthupper mantlecompositionsiderophiletrace