Heterogeneities of hydrocarbon compositions in mudstones of a turbiditic sequence of the Miocene Kawabata Formation in Yubari, central Hokkaido, Japan

• OKANO KAZUKI

  Department of Natural History Sciences, Faculty of Science, Hokkaido University

• SAWADA KEN

  Department of Natural History Sciences, Faculty of Science, Hokkaido University

Bibliographic Information

Other Title

• Heterogeneties of hydrocarbon compositions in mudstones of a turbiditic sequence of the Miocene Kawabata Formation in Yubari, Central Hokkaido, Japan

Abstract

Biomarker analyses of aliphatic and aromatic hydrocarbons were conducted on the upper and lower parts of individual mudstones in a turbiditic sequence of the Miocene Kawabata Formation, Yubari, central Hokkaido, Japan. The relative abundances of terrigenous biomarkers such as long-chain n-alkanes, C₂₉ steranes and oleanenes as well as biomarkers produced in coastal areas such as dinosteranes tend to be higher in the lower parts of mudstones than those of the upper ones in the turbiditic sequence. Also, pristane/phytane ratios, which are proxies for depositional environment, significantly vary between the upper and lower parts of mudstones in the turbiditic sequence. These results suggest that these variations reflect the types and phases of transport and redeposition by turbidity systems rather than postdepositional diagenesis. Such heterogeneous distributions in most of biomarker compositions within the mudstone layers may lead to a severe bias for reconstructing paleoenvironment and paleoecology. Nevertheless, the higher plant parameters (HPPs) such as the retene/cadalene ratios are consistently homogenous within the mudstones. Moreover, paleovegetation reconstructed from HPPs are concordant with a previous paleobotanical study. Thus, it seems that these biomarker records in the turbidite sediments are reliable and strongly applicable for reconstructing terrestrial paleovegetation.

Journal

• GEOCHEMICAL JOURNAL

  GEOCHEMICAL JOURNAL 42 (2), 151-162, 2008

  GEOCHEMICAL SOCIETY OF JAPAN

Keywords

• hydrocarbon biomarker
• turbiditic sequence
• geochemical heterogeneity
• terrigenous material transport
• paleoenvironment

Details

• CRID: 1390001204549934336
• NII Article ID: 10021093226
• NII Book ID: AA00654975
• DOI: 10.2343/geochemj.42.151
• COI: 1:CAS:528:DC%2BD1cXnsl2gs74%3D
• ISSN: 18805973
• ISSN: 00167002
• NDL BIB ID: 9470214
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I9470214
• Text Lang: en
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed