The nature of Ordovician limestone-marl alternations in the Oslo-Asker District (Norway): Witnesses of primary glacio-eustasy or diagenetic rhythms?

Journal article
(Original article)


Publication Details

Author(s): Amberg CEA, Collart T, Salenbien W, Egger LM, Munnecke A, Nielsen AT, Monnet C, Hammer Ø, Vandenbroucke TR
Journal: Scientific Reports
Publisher: Nature Publishing Group
Publication year: 2016
Volume: 6
ISSN: 2045-2322
Language: English


Abstract


Ordovician limestone-marl alternations in the Oslo-Asker District have been interpreted as signaling glacio-eustatic lowstands, which would support a prolonged â €œ Early Palaeozoic Icehouseâ €. However, these rhythmites could alternatively reflect differential diagenesis, without sedimentary trigger. Here, we test both hypotheses through one Darriwilian and three Katian sections. Our methodology consists of a bed-by-bed analysis of palynological (chitinozoan) and geochemical (XRF) data, to evaluate whether the limestone/marl couplets reflect an original cyclic signal. The results reveal similar palynomorph assemblages in limestones and marls. Exceptions, which could be interpreted as reflecting palaeoclimatological fluctuations, exist at the species level: Ancyrochitina bornholmensis seems to be more abundant in the marl samples from the lower Frognerkilen Formation on Nakkholmen Island. However, these rare cases where chitinozoans differ between limestone/marl facies are deemed insufficient for the identification of original cyclicity. The geochemical data show a near-perfect correlation between insoluble elements in the limestone and the marls, which indicates a similar composition of the potential precursor sediment, also in the Frognerkilen Formation. This is consistent with the palynological data. Although an original cyclic pattern could still be recorded by other, uninvestigated parameters, our palaeontological and geochemical data combined do not support the presence of such a signal.



FAU Authors / FAU Editors

Munnecke, Axel Prof. Dr.
Professur für Paläontologie (Schwerpunkt Faziesanalyse)


External institutions
Duke University
LILLE 1 University - Science and Technology
Ruprecht-Karls-Universität Heidelberg
Universiteit Gent (UGent) / Ghent University
University of Copenhagen
University of Oslo


How to cite

APA:
Amberg, C.E.A., Collart, T., Salenbien, W., Egger, L.M., Munnecke, A., Nielsen, A.T.,... Vandenbroucke, T.R. (2016). The nature of Ordovician limestone-marl alternations in the Oslo-Asker District (Norway): Witnesses of primary glacio-eustasy or diagenetic rhythms? Scientific Reports, 6. https://dx.doi.org/10.1038/srep18787

MLA:
Amberg, Chloé E. A., et al. "The nature of Ordovician limestone-marl alternations in the Oslo-Asker District (Norway): Witnesses of primary glacio-eustasy or diagenetic rhythms?" Scientific Reports 6 (2016).

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Last updated on 2018-08-08 at 04:37