Carbon isotope fluctuations of terrestrial organic matter for the Upper Cretaceous (Cenomanian–Santonian) in the Obira area of Hokkaido, Japan

Abstract

Stratigraphic fluctuations of carbon isotope values of terrestrial organic matter within the Upper Cretaceous (Cenomanian-Santonian) sequence in the Obira area of Hokkaido, Japan, record distinctive δ 13 C fluctuations for the Cenomanian-Turonian boundary, the Middle Turonian, the upper Turonian-lower Coniacian, and the Santonian. A biostratigraphic framework of the agediagnostic taxa (ammonoids, bivalves and planktic foraminifers) indicates that these δ 13 C fluctuation events are comparable with those recorded in δ 13 C data of terrestrial organic matter in Japan and marine carbonates in Europe. These correlations reinforce the utility of these δ 13 C events in terms of global chemostratigraphy. In particular, the δ 13 C patterns within the overall positive interval of the Cenomanian-Turonian boundary event are highly conformable between marine and terrestrial records. The consistent nature of these different records of δ 13 C fluctuation patterns demonstrates that the terrestrial organic δ 13 C data mirror the global-scale δ 13 C patterns in the carbon reservoir of oceanatmosphere-terrestrial biosphere during the Cenomanian-Turonian boundary event. In addition, global correlation of short-term marine and terrestrial organic δ 13 C fluctuations of the Upper Cretaceous sequence indicate that the magnitude of several terrestrial organic δ 13 C events appears more amplified than that of coeval marine carbonate δ 13 C events. This correlation is interpreted to mean that the effects of local CO 2 emission into the atmosphere by release of terrestrial methane hydrate or biomass burning of terrestrial vegetation in the hinterland of the NE Asian region have been superimposed on the global δ 13 C trend and resulted in the terrestrial organic δ 13 C records of the Yezo Group.

A revised inoceramid biozonation for the Upper Cretaceous based on high-resolution carbon isotope stratigraphy in northwestern Hokkaido, Japan

“…Hasegawa (1997) discussed the resemblance between the δ 13 C curves for marine carbonates and those for terrestrial organic matter, and concluded that the δ 13 C stratigraphy of terrestrial organic matter provides a reliable tool for correlation with the marine carbonates. Recently, Uramoto et al (2009) supported the usefulness of this tool for correlation and indicated that δ 13 C fluctuations of terrestrial organic matter reflected the global isotopic patterns in the carbon reservoir of the ocean-atmosphere-terrestrial biosphere system. The δ 13 C-based correlations first require, however, determination of the approximate geological ages, based usually on biostratigraphy and complete stratigraphic successions.…”

“…The Hydrogen Index (HI) is the ra- Haboro R. Haboro R. The study areas. The northern rectangle is the Haboro area, the southern area is the Obira area, the middle rectangle with dashed line (a) is the Kotanbetsu area studied by Takashima et al (2010), and the southern rectangle with dashed line (b) is the area studied by Uramoto et al (2007Uramoto et al ( , 2009). (C) Geological map of the Haboro area.…”

“…Although Uramoto et al (2009) demonstrated the δ 13 C stratigraphy in the Obira area, the sampling intervals for the Coniacian were rather coarse, and their δ 13 C record was limited to the Santonian. In the present study, higherresolution δ 13 C data are reported, and the analysis spans the Coniacian through to the lower Campanian.…”

“…8). The δ 13 C TOM profiles for the Obira area in this study and that of Uramoto et al (2009) were integrated because the δ 13 C TOM profile in this study overlaps with part of the profile of Uramoto et al (2009) and the fluctuation patterns of these profiles are the same in the overlapped section along the Obirashibe and Okufutamatazawa rivers. The lowest occurrences of the ammonoid Yokoyamaoceras ishikawai (Jimbo) and the inoceramid bivalve Didymotis costatus (Fric) were used as regional stratigraphic markers to correlate the δ 13 C TOM profiles of these three areas.…”

“…Temporal fluctuations in the carbon isotope ratios (δ 13 C) of marine carbonates are a reliable tool for regional and international correlations (e.g., Jenkyns et al 1994;Erbacher et al 1996;Voigt and Hilbrecht 1997;Stoll and Schrag 2000;Voigt 2000;Jarvis et al 2002Jarvis et al , 2006Voigt et al 2010). In Japan, δ 13 C stratigraphic studies on terrestrial organic matter have been undertaken for the Yezo Group (Hasegawa 1992;Hasegawa and Saito 1993;Hasegawa 1997;Hirano and Fukuju 1997;Hasegawa and Hatsugai 2000;Ando et al 2002Ando et al , 2003Hasegawa et al 2003;Ando and Kakegawa 2007;Uramoto et al 2007Uramoto et al , 2009Takashima et al 2010). Hasegawa (1997) discussed the resemblance between the δ 13 C curves for marine carbonates and those for terrestrial organic matter, and concluded that the δ 13 C stratigraphy of terrestrial organic matter provides a reliable tool for correlation with the marine carbonates.…”