Platinum group elements and Re in marine sediments across the K-T boundary: constraints on Re-PGE transport in the marine environment

The nature of Re-PGE (PGE = Pt, Pd, Ir, Os, Ru) transport in the marine environment was investigated using marine sediments at and across the Cretaceous-Tertiary boundary (KTB) at two hemipelagic sites and two pelagic sites. A traverse across the KTB in a south Pacific pelagic clay core found elevated levels of Re, Pt, Ir, Os and Ru, each of which is symmetrically distributed over ~1.8 m across the KTB. The Re-PGE abundance patterns are fractionated from chondritic relative abundances: Ru, Pt, Pd, and Re contents are slightly subchondritic relative to Ir, and Os is depleted by ~95%.