13C/12C ratio double cyclicity in a Miocene browncoal: isotopic signals and orbital forcing

Terra Nova - Tập 9 Số 1 - Trang 19-23 - 1997
Timothy Peter Jones1, Steven M. Fortier2, Volker Mosbrugger1, J Roessler1, Thorsen Utescher3, Abdul Rahman Ashraf3
1Institut und Museum für Geologie und Paläontologie, Universität Tübingen, Sigwartstrasse 10, D‐72076 Tübingen, Germany
2Institut für Mineralogie, Petrologie und Geochemie, Universität Tübingen, Wilhelmstrasse 56, D‐72074, Germany,
3Institut für Paläontologie der Universität Bonn, Nussallee 8. D-53115 Bonn, Germany

Tóm tắt

A detailed stable carbon isotopic profile of a late Miocene browncoal seam from the Lower Rhine Embayment, Germany, reveals two clear separate cycles of different frequency: this is the first instance of this type of isotopic signature being recognized within coals. The ratio of the two frequencies suggests this isotopic signal possibly resulted from climatic or vegetational responses to orbital forcing. The cyclicity has been enhanced by the application of conventional filtering methods on the data set. An analysis of the seam’s palynology indicates a correlation between heavier isotopic compositions and the presence of Sequoiapollenites polyformosus, whose parent plant is believed to have favoured moist climates and higher groundwater tables.

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Terra Nova

Tập 9 Số 1

19-23

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