Palynological studies on manganese ore layers in Úrkút (Transdanubia), Hungary

Abstract

Samples of manganese carbonate and oxide layers from the Úrkút ore deposit were investigated for organic remains, especially for spores and pollen grains. Light (LM), Transmission Electron (TEM), and Scanning Electron Microscopy (SEM) methods were used. LM revealed several new sporomorph taxa; a microstratigraphic standard was established by reconstructing vegetation zones surrounding the sedimentary basin. Index fossils of palynomorphs and the relative abundance of other taxa support a Liassic (Lower Jurassic) age for these layers. TEM data were used to establish: (1) important new understanding about the phylogeny of the pollen-exine ultrastructure and, in particular, the tectate columellar ectexine of the Mesozoic gymnospermous pollen grain, Spheripollenites; and (2) the degree of destruction of the exine ultrastructure helps to reconstruct taphonomical processes during sedimentation and to unravel biopolymer-type molecular structures in the walls of palynomorphs. The SEM method aided in the taxonomy of the microfossils. Combined TEM and SEM methods revealed that submicroscopic surface degradation may be a consequence of bio-degradation during deposition of manganese ore.