Upper Pleistocene biostratigraphy and traces of glaciotectonics at the Satiki site, western Latvia

摘要

Structural, lithological, palynological and plant macroremain investigations of test-boring cores and gravel pit walls at the Satiki site suggest that gyttja and sandy gyttja units of basin sediments were deposited during the Felicianova (Eemian) Interglacial. A pollen diagram reflects the characteristic forest succession of the Eemian Interglacial: Betula, Pinus, Ulmus, Corylus, Quercus, Fraxinus, Tilia, Carpinus, Picea and Pinus. Forests of broadleaved trees and thermophilous plants dominated in the surroundings of the lake during the interglacial climatic optimum. The basin sediments contain a large number of warmth-demanding water plants such as Salvinia natans and Trapa sp. Paleobotanical studies indicate that the sequence is continuous and complete, although the interglacial basin sediments are incorporated in till. Erratic megaclasts of Upper Devonian sandstones, siltstones, clays and dolostones found in a gravel pit close to the Satiki paleobasin are glaciotectonically deformed, pushed, and brecciated. The sedimentary body of the Satiki paleobasin may have been deformed and altered to some extent during the Weichselian glaciation.