A reconstruction of the environment of Rettig in the city of Turku, Finland on the basis of diatom, pollen, plant macrofossil and phytolith analyses

VUORELA, I., GRÖNLUND, T. & LEMPIÄINEN, T., 1996: A reconstruction of the environment of Rettig in the city of Turku, Finland on the basis of diatom, pollen, plant macrofossil and phytolith analyses. Bull. Geol. Soc. Finland 68, Part 2, 46-71. Palynological and palaeobotanical results from three representative cores investigated in 1994—1995 in connection with the archaeological excavations in the Rettig "Palace", Turku, Finland, are discussed. The cultural layer consisted of a heterogeneous urban upper stratum and a more humid and more homogeneous lower stratum, all resting on a clay sequence several metres thick. A chronological series of marine clay, partly river-washed and redeposited clay, and clayey soil characterized by aerophilous diatoms was determined. Diatom analysis was used to reconstruct sedimentation environment and the development of the natural landscape in relation to land uplift. Pollen analysis was used to trace the transformation of the natural landscape into a cultural landscape and finally into an urban settlement area. The pollen results were complemented by those on plant macrofossils, which consisted of the remnants of 124 species of many different groups, such as natural, cultivated, imported, medical and collected plants. Phytoliths were investigated from the surface material of a grindstone found on the site, and typical morphotypes were described although no typical cereal phytoliths could be identified.