Os isotope and platinum group elements (PGE) analysis have been increasingly used now for tracing geologic events that are reflected in the geochemistry of contemporaneous sedimentary sequences. The use of PGEs only as extraterrestrial tracer became important since the discovery of Ir anomalies at the Cretaceous-Tertiary boundary (KTB). Since then, numerous sites have been found with reported Ir anomalies although only a few had been confirmed to be impact sites based on sedimentological, mineralogical, and discovery of associated impact craters. A potential problem for marine sediments as recorders of extraterrestrial event is that the behavior of the PGEs in oceanic environment is largely unknown and can be different depending on the Eh condition and the effect of volcanogenic hydrothermal activity and post depositional remobilization. The use of Os isotopes in combination with the PGE determination can help better constrain the origin of PGE anomalies in marine sediments (1-2). We apply a similar method of combining Os isotopes and PGE determination to investigate whether a bolide impact had something to do with the contemporaneous massive volcanism (Ontong Java Plateau event) and oceanic anoxic event (OAE 1a) in Early Cretaceous, 120 million years ago.