Preprints
https://doi.org/10.5194/cp-2021-81
https://doi.org/10.5194/cp-2021-81

  23 Jul 2021

23 Jul 2021

Review status: this preprint is currently under review for the journal CP.

Early Eocene carbon isotope excursions in a lignite bearing succession at the southern edge of the proto-North Sea (Schöningen, Germany)

Olaf K. Lenz1,2, Mara Montag2, Volker Wilde1, Katharina Methner3,5, Walter Riegel1, and Andreas Mulch3,4 Olaf K. Lenz et al.
  • 1Senckenberg Research Institute and Natural History Museum Frankfurt, 60325 Frankfurt am Main, Germany
  • 2Institute of Applied Geosciences, Technical University Darmstadt, 64287 Darmstadt, Germany
  • 3Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Senckenberganlage 25, 60325 Frankfurt am Main, Germany
  • 4Institute of Geosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
  • 5Department of Earth System Science, Department of Geological Sciences, Stanford University, USA

Abstract. Situated at the southern edge of the proto-North Sea the lower Eocene Schöningen Formation of the Helmstedt Lignite Mining District, Lower Saxony, Germany is characterized by several lignite seams alternating with estuarine to brackish interbeds. Here, we present carbon isotope data of bulk organic matter (δ13CTOC), organic carbon content (%TOC), and palynomorphs from a 98 m thick sequence of the Schöningen Formation embedded into a new robust age model. This is based on eustatic sea-level changes, biostratigraphy, and a correlation to existing radiometric ages. Based on the δ13CTOC data we observe six negative carbon isotope excursions (CIEs) reflecting massive short-term carbon cycle perturbations. A strong CIE of −2.6 ‰ in δ13CTOC values in the Main Seam and the succeeding marine interbed can be related to the Paleocene–Eocene Thermal Maximum (PETM). The subsequent CIE of −1.7 ‰ in δ13CTOC values may be correlated with the Eocene Thermal Maximum 2 (ETM2) or slightly older events preceding the ETM2. High-amplitude climate fluctuations including at least 4 minor CIEs with a maximum negative shift of −1.3 ‰ in δ13CTOC in the upper part of the studied section are characteristic for the EECO. Palynological analysis across the Main Seam proved that shifts in δ13CTOC values are correlated with changes in the peat forming wetland vegetation, specifically the change from a mixed angiosperm and gymnosperm flora to an angiosperm dominated vegetation at the onset of the PETM. The PETM-related CIE shows a distinct rebound to higher δ13CTOC values shortly after the onset of the CIE, which is here recognized as a common feature of terrestrial and marginal marine PETM-records worldwide and may be related to changes in the vegetation including different carbon isotope budgets of gymnosperms and angiosperms.

Olaf K. Lenz et al.

Status: open (until 22 Oct 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Olaf K. Lenz et al.

Olaf K. Lenz et al.

Viewed

Total article views: 336 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
284 48 4 336 24 2 4
  • HTML: 284
  • PDF: 48
  • XML: 4
  • Total: 336
  • Supplement: 24
  • BibTeX: 2
  • EndNote: 4
Views and downloads (calculated since 23 Jul 2021)
Cumulative views and downloads (calculated since 23 Jul 2021)

Viewed (geographical distribution)

Total article views: 319 (including HTML, PDF, and XML) Thereof 319 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 21 Sep 2021
Download
Short summary
We describe different carbon isotope excursions (CIE) in a Paleocene to lower Eocene lignite succession (Schöningen, DE) . The combination with a new stratigraphic framework allows for an exact correlation of distinct CIEs to long- and short-term thermal events of the last natural greenhouse period on Earth. Furthermore, changes in the peat forming wetland vegetation are correlated with a CIE that can be can be related to the Paleocene–Eocene Thermal Maximum (PETM).