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

Abstract

ABSTRACT:Hayakawa, T., Hirano, H. 2013. A revised inoceramid biozonation for the Upper Cretaceous based on high-resolution carbon isotope stratigraphy in northwestern Hokkaido, Japan. Acta Geologica Polonica, 63 (2), 239-263. Warszawa.Biostratigraphic correlations of inoceramid bivalves between the North Pacific and Euramerican provinces have been difficult because the inoceramid biostratigraphy of the Japanese strata has been based on endemic species of the northwest Pacific. In this study, carbon stable isotope fluctuations of terrestrial organic matter are assembled for the Upper Cretaceous Yezo Group in the Haboro and Obira areas, Hokkaido, Japan, in order to revise the chronology of the inoceramid biozonation in Japan. The carbon isotope curves are correlated with those of marine carbonates in English and German sections with the aid of age-diagnostic taxa. According to the correlations of the carbon isotope curves, 11 isotope events are recognised in the sections studied. As a result of these correlations, the chronology of the inoceramid biozones of the Northwest Pacific has been considerably revised. The revised inoceramid biozones suggest that the timing of the origination and extinction of the inoceramids in the North Pacific biotic province is different from the stage/substage boundaries defined by inoceramids, as used in Europe and North America.

Intercontinental correlation of organic carbon and carbonate stable isotope records: evidence of climate and sea‐level change during the Turonian (Cretaceous)

“…Tethyan planktonic foraminifera marker species are rare or absent from the Yezo Group, necessitating the application of a regional foraminifera biostratigraphy (Nishi et al ., ), calibrated using records of occasional international markers. The regional macrofossil biostratigraphy principally employs endemic inoceramid bivalve assemblages, calibrated to the international timescale using occasional co‐occurring Tethyan ammonites and inoceramid species (Toshimitsu et al ., ; Hayakawa & Hirano, ). The latter have only been recorded sporadically from any of the carbon isotope study sections.…”

“…The resulting correlation (Fig. ) differs from previous work (Takashima et al ., ; Hayakawa & Hirano, ; Uramoto et al ., , ) in recognizing a higher Upper Turonian turning point in isotope profiles from organic matter compared to δ 13 C carb curves, and correlating the turning point at Kotanbetsu to the Běchary HW2 CIE, rather than the older Hitch Wood CIE. This reinterpretation is supported by the FO M. sinuosa , a high Upper Turonian marker, coincident with HW2.…”

“…The isotopic linkage between marine and terrestrial carbon reservoirs means that carbon isotope stratigraphy is potentially a powerful tool for high‐resolution correlation between marine and non‐marine successions. Extensive work has been undertaken on characterizing δ 13 C trends in bulk terrestrial organic matter in the Turonian Yezo Group of Japan (Hasegawa & Saito, ; Hasegawa, , ; Hasegawa & Hatsugai, ; Hasegawa et al ., ; Tsuchiya et al ., ; Uramoto et al ., , , ; Hayakawa & Hirano, ; Takashima et al ., , ), enabling comparison to marine δ 13 C records.…”

“…However, northern hemisphere‐wide water‐mass reorganization is indicated by the a temporary influx during Interval III of Prionocyclus ammonites from the North American Western Interior Seaway (WIS), which are widely distributed in northern Germany and the Czech Republic, through southern Spain to Tunisia (Robaszynski et al ., ). At the same time, several belemnite taxa migrated eastwards from Greenland (Košťák & Wiese, ), and a connection to Japan is suggested by the occurrence of Mytiloides incertus Jimbo in both Europe and Japan (Voigt, ; Takahashi, ; Hayakawa & Hirano, ).…”

“…The recognition of key Turonian carbon CIEs in the terrestrial carbon record offers an opportunity to further refine the calibration of the biostratigraphy of the endemic mollusc faunas in the NW Pacific to the international timescale (cf. Hayakawa & Hirano, ). In addition, there is potential for dating fully non‐marine Turonian successions barren of fossils, although here a long and detailed time series will be required, and an absence of major hiatuses is essential to correctly identify major isotope shifts that can be assigned to specific CIEs.…”