A generalized lithofacies model for glaciomarine and marine sequences in the Göteborg area, Sweden

Abstract

G., 1990 06 15: A generalized lithofacies model for glaciomarine and marine sequences in the Goteborg area, Sweden. Geologiska Foreningens i Stockholm Forhandlingar, Vol. 112, Pt. 2, pp. 89-105. Stockholm. ISSN 0016-786X. Strong stratigraphic trends can be recognized at many, if not most, of the valley localities below the marine limit in the Goteborg area. The deposits reflect the deglaciation and the isostatically induced regression following the last Weichselian glaciation. The generalized sequence of paleoenvironments and their associated deposits are used as an initial basis for comparing three stratigraphic examples from SW Sweden. These interpreted sections, in turn, are used to improve the paleogeographic model by specifying typical variations in important environmental parameters not originally included in the model. Ice-front proximity and meltwater drainage are decisively involved in the supply of sediments to both proximal and distal glaciomarine settings. Climatic variations further determine the extent of this supply and the balance between the contribution from the glacial source and the increasingly important supply from local erosion. Sedimentologic facies are described and discussed with respect to environmental interpretations in these late Quaternary, finegrained sequences. The lithofacies model reflects changes that are often time-transgressive between localities, but nevertheless comparable due to the similar depositional conditions. The resulting facies model can help in the observational, comparative and interpretive phases of an investigation. 0 Goteborg. Sweden, stratigraphic model. Weichselian deglaciation, environmental evolution, glaciomarine and marine. fine-grained sediments, sedirnentation rates, vanes, depositional processes, iron sulfides, textural fiatures. Rodney L. Stevens, Geologiska institutionen, Chahners tekniska h6gskola/Goteborgs unirersitet. S-412 96 Goteborg. Sweden, and Lars-Gunnar Ilellgren. Stadsbyggnadskontoret, Box 2554, S-403 17 Goteborg. Sweden. hiannuscript

A high‐resolution record of Lateglacial and early Holocene marine sediments from southwestern Sweden; with special emphasis on environmental changes close to the Pleistocene‐Holocene transition and the influence of fresh water from the Baltic basin

“…5.4 and 8 m (zones F2-F3) show high clay and water contents, very low cation contents, geotechnically high sensitivity and a very characteristic foraminiferal fauna dominated by E. excavatum f. albal selseyensis (96-99%). This significant unit, termed unit B in the HG core, is correlated stratigraphically with units previously investigated elsewhere in southwestern Sweden (Cato, 1981 ;Freden eta/., 1981 ;Olausson, 1982;Bergsten and Denneghd, 1988;Klingberg, 1989;Stevens and Hellgren, 1990) that show these same characteristics. In the HG core this unit begins with a relatively coarse bed (8.10-8.15 m) containing a foraminiferal fauna dominated by E. albiumbilicaturn together with E .…”

“…The 'Pleistocene-Holocene working group' (Olausson, 1982), as well as other authors have interpreted the characteristic unit B as being a direct response to the final drainage of the BIL and the subsequent few hundred years during the late Younger Dryas and early Preboreal (Cato et a/., 1982;Klingberg, 1989;Stevens and Hellgren, 1990;Stevens et a/., 1991). The chronostratigraphical basis for this interpretation is neither supported by good conventional radiocarbon dates, AMS dates nor distinct pollen spectra.…”

“…This very characteristic sequence has been linked previously to the BIL final drainage event (e.g. Cat0 et a/., 1982;Klingberg, 1989;Stevens and Hellgren, 1990;Stevens et a/., 1991) at 10300 yr BP. In the late 1970s and early 1980s an international working group (Olausson, 1982) carried out a study in search of a high-resolution Pleistocene-Holocene boundary stratotype locality in a former marine near-shore environment in the Goteborg and Bohuslan Province (Fig.…”

Late Weichselian marine stratigraphy of the southern Kattegat, Scandinavia: evidence for drainage of the Baltic Ice Lake between 12,700 and 10,300 years BP

“…Cato (1981), Freden et al (1981), Cat0 et al (1982), Olausson (1982), Bergsten (1989), Klingberg (1989) and Stevens & Hellgren (1990) describe a clay sequence in the Goteborg region characterized by light 6 '*O values, high clay and water contents, very low cation content, freshwater diatoms and an extreme foraminiferal fauna.…”

Mapping areas of potential slope failures in cohesive soils using a shadow-casting algorithm – A case study from SW Sweden

“…Most of the area is situated below the highest post-glacial sea level [1] and the thickness of the fine grained sediments may approach 100 m [1]. The clays in the region are mainly glaciomarine [21], which means that high sensitive clays has developed at places where post-glacial soft groundwater flow has drastically changed the original composition of the pore fluid of the clay.…”