Data sets include the osmium and carbon isotopic information of the limestone samples collected from the Fiume Bosso section (43°31'07.2N 12°34'15.4E), central Italy. Os and carbon isotopic measurements were conducted from December 2019 to October 2020 to reconstruct paleo-marine Os and carbon isotopic variations. Os isotopic ratios were measured with thermal ionization mass spectrometry (TRITON, Thermo Fisher Scientific, USA) and carbon isotopic ratio were measured with isotope ratio mass spectrometry (Delta V plus, Thermo Fisher Scientific, USA). Our data covers from the upper Hauterivian to the lower Barremian of the Lower Cretaceous.

FB51* was excluded from our discussion.