Organic compound analyses in the sediments at the Cretaceous/Tertiary and the Permian/Triassic boundary, and study of environmental changes at those time.

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n-Alkanes, isoprenoid hydrocarbons, cyclic hydrocarbons, aromatic hydrocarbons, amino acids, fatty acids, dicarboxylic acids, maleimides and carbazoles in the Cretaceous/Tertiary boundary sediments at Kawaruppu, Hokkaido, Japan were analyzed. Depth profiles of amounts of n-alkanes, isoprenoid hydrocarbons, cyclic hydrocarbons, fatty acids, maleimides and carbazoles resembled each other. Amounts of those compounds were almost same in the Cretaceous samples, and those in the Tertiary samples were nearly 2/3 of those in the Cretaceous samples. Those in the lower 2/3 of the boundary claystone were extremely small and those in the upper 1/3 of the boundary claystone were gently recover to the level in the Tertiary samples. This pattern is thought that as a reflection of biomass at that time. Diagenetic indices as CPI values of n-alkanes and fatty acids, isomer ratios of alkylaromatics, enantiomeric ratios of dicarboxylic acids, and diasteromeric ratios of steranes and hopanes were almost co … More nstant through the all sample horizons. Therefore, thermal alteration in the boundary calystone is not different from that in the Cretaceous and Tertiary samples. Any evidence of extraterrestrial organic compounds were not found in the all sample horizons.n-Alkanes, isoprenoid alkanes and aromatic hydrocarbons in the Permian/Triassic boundary sediments at Tenjin-Maru, Tokushima, Japan were analyzed. Steranes and hopanes were not found in the P/T samples and would be degraded during 250 million years. Ratios of pristane to phytane in the middle of the boundary black chart were higher than 1.0 and those in the other sample horizons were lower than 1.0. This result shows that sedimentation condition in the middle of the boundary black chart is rather oxic than super anoxic condition. Ratios of pyrene to chrysene, ratios of 2-methyl- to 1-methylnaphthalene in the middle of the boundary black chart were higher than those in the other sample layers. It shows the extremely high temperature condition as wide wild fires at that time. Less