Abstract

Comparative studies are made on the development of lamination in Recent, Paleogene and Permian lake sediments. The study concentrates on the relationship between primary production and lamina formation. The main phytoplankton development in lakes is correlated with environmental changes and it is often preserved in the lamination in chronological succession. Seasonal patterns may be especially represented. Morphological identification and classification of laminities is achieved by studies of Recent lake sediments. This leads to possible comparison, even in badly preserved ancient examples. Paleogene lamination can be clearly correlated with the Recent lamination by the relatively tenuous relationships of the phytoplankton. Permian lake sediments, however, are difficult to decipher, as the phytoplankton species are different or absent as a result of taphonomy. Nevertheless, morphological comparisons suggest periodic sedimentation and lamination development that is clearly similar to that in lakes today. As the same physical properties apply, this seasonal sedimentation can also be used as an additional tool for the reconstruction of environmental and climatic changes in the Carboniferous-Permain boundary strata.