Occurrence of natural fullerene C60 from the iridium-rich Cretaceous-Paleogene (K-Pg) boundary layers of the Um-Sohryngkew river section, Meghalaya, India

Abstract

The presence of fullerene C₆₀ in the iridium-rich Cretaceous-Palaeogene (K-Pg) boundary layer from the Um-Sohryngkew river section of Meghalaya is reported here for the first time. Different analytical methods, including transmission electron microscopy (TEM), Raman spectroscopy, Fourier transform infrared (FT-IR), and X-ray diffraction(XRD) techniques, have been used to characterize the presence of toluene-insoluble high-pressure phase of fullerene C₆₀ in the acid resistant carbonaceous matter extracted from the Um-Sohryngkew river section, Meghalaya, India. Strong absorption peaks at wavenumbers 1427, 1181, 574, and 525 cm⁻¹, which are indicative of pristine fullerene C₆₀, can be seen in the FTIR spectroscopic study. The Raman spectrum also independently confirms the presence of fullerene, by exhibiting the characteristics peaks of pristine fullerene C_60. The XRD technique provides further, independent validation of fullerenes, and the XRD pattern demonstrates fullerene presence. Fullerenes, high-pressure fullerene, the amorphous phase of C₆₀, and iridium all coexist and offer conclusive proof of impact at the Cretaceous-Palaeogene (K-Pg) boundary extinction event.