The recolonisation of volcanically disturbed Eocene habitats of Central Europe: the maar lakes of Messel and Offenthal (SW Germany) compared

Maryam Moshayedi,Volker Wilde,Olaf K Lenz,Matthias Hinderer

doi:10.1007/s12549-020-00425-4

Abstract

To reconstruct the palaeoenvironment and changes within the vegetation, 68 core samples were analysed palynologically from the lacustrine filling of the Eocene maar lake of Offenthal (Hesse, SW Germany). The lacustrine succession includes 16 m of clastic sediments overlain by 13 m of finely laminated bituminous shale. Based on a revised 40Ar/39Ar age of ~ 47.8 ± 0.3 Ma, the lacustrine filling at Offenthal can be dated as uppermost lower Eocene to lowermost middle Eocene which is almost coeval to part of the nearby lacustrine succession at Messel. Cluster and non-metric multidimensional scaling (NMDS) analyses of well-preserved palynomorph assemblages reveal successional stages during the recolonisation of the maar lake and its surroundings which are related to lithological changes. Furthermore, the palynomorph assemblages from Offenthal are compared with assemblages from Messel by NMDS analysis to find similarities and differences during the recolonisation of volcanically disturbed habitats in Central Europe during Paleogene greenhouse conditions. Based on the similar succession in the vegetation at both lakes, four different phases can be distinguished during recolonisation and reestablishment of the vegetation at these sites: (1) an initial phase, (2) a recolonisation phase, (3) a recovery phase, (4) a climax phase.

Highlights

Since it was the last greenhouse period on Earth and ecosystems already consisted of modern-type floras and faunas, the Paleogene has been intensely studied to understand the response of ecosystems to environmentalElectronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.There are at least half a dozen Eocene basins exposing lacustrine sediments known on the Sprendlinger Horst near Darmstadt in Southwest Germany (Fig. 1)
Samples were prepared using standard palynological extraction techniques as described by Kaiser and Ashraf (1974). They were successively treated by hydrochloric acid (HCL), hydrofluoric acid (HF) and potassium hydroxide (KOH)
The different distribution of early colonisers such as ferns represented by spores such as Leiotrilites spp., Trilites spp., Verrucatosporites favus and Polypodiaceoisporites spp. in PZ 1, PZ 2 and PZ 3a, which are plotted on the right side of the non-metric multidimensional scaling (NMDS) ordination space (Fig. 7b) reveal a successive vegetational recolonisation in the lower part of the record

Summary

Introduction

Since it was the last greenhouse period on Earth and ecosystems already consisted of modern-type floras and faunas, the Paleogene has been intensely studied to understand the response of ecosystems to environmental. There are at least half a dozen Eocene basins exposing lacustrine sediments known on the Sprendlinger Horst near Darmstadt in Southwest Germany (Fig. 1). Most of them are fillings of maar structures resulting from hydro-volcanic activity, such as Messel, Offenthal and Groß-Zimmern (Jacoby 1997; Harms et al 1999; Jacoby et al 2000; Felder et al 2001; Felder and Harms 2004). Maar lake sediments are excellent for the Palaeobio Palaeoenv 49°55’N UpGrpaerbeRnhine 8°E 16°E 8°40’E 8°45’E 8°50’E 8°55’E Seligenstadt

Methods

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Discussion

Conclusion