Abstract
Fine-grained sediments in southern Finland were deposited during the retreat of the continental Fennoscandian ice-sheet at around 13,000 cal BP, leaving subsequent ice-contact deposits and postglacial lake and, finally, the modern brackish water Baltic Sea basin (BSB). As a result of the strong glacioisostatic land uplift of the region, these sediments today lie above sea-level in coastal Finland. The recent expansion of cities to locations where superficial sediments are more challenging for construction purposes has increased the need for comprehensive understanding of the properties and geometry of these fine-grained superficial deposits. Commonly used site-specific lithostratigraphical characteristics of clayey deposits run the risk of ambiguous correlation between sites because of different types of postglacial depositional settings. The present study applies an allostratigraphical approach to classify late- and postglacial clayey deposits using examples from four sedimentary basins in the vicinity of the city of Espoo along the southern coast of Finland. This entails a reinterpretation of 17 core logs collected during the period 2006–2009 and reported in earlier studies, combined with examination of five new cores collected in 2016 coupled with borehole measurements of resistivity-temperature and electrical resistivity tomography (ERT). Physical proxies and sediment characteristics demonstrate that grey postglacial lacustrine silty (Ancylus Lake) clay is truncated at the top by an undulating erosional surface (unconformity), which is covered by a silt to sand layer a few centimetres thick that has a gradual-bioturbated upper contact to the greenish-grey brackish water (Litorina Sea) mud. Sediments above and below the unconformity are intensely bioturbated, and black mottling of Fe-monosulphide is observed in the brackish water mud. Evidently, this unconformity is of high engineering-geological significance because the organic-rich brackish water mud has a poorer bearing capacity and higher abundance of sulphide minerals that form sulphuric acid upon oxidation. It is demonstrated that this unconformity is spatially well recognised and provides a key stratigraphic marker for wider and more accurate comparison between sites with fine-grained deposits in the Helsinki metropolitan area and potentially in other urban areas in the northern Baltic Sea region.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Andersson M, Norrman T (2004) Stabilisering av sulfidjord. En litteratur-och laboratoriestudie. Arbetsrapport 33, 2004–2006. Swedish Deep Stabilization Research Centre, Linköping, p 102
Antrop M (2000) Changing patterns in the urbanized countryside of western Europe. Landscape Ecol 15:257–270
Antrop M (2004) Landscape change and the urbanization process in Europe. Landscape Urban Plan 67:9–26
Åström M, Björklund A (1997) Geochemistry and acidity of sulphide bearing postglacial sediments of western Finland. Environ Geochem Hlth 19:155–164
Björck S (1995) A review of the history of the Baltic Sea, 13.0–8.0 ka BP. Quatern Int 27:19–40
Brookfield ME, Martini IP (1999) Facies architecture and sequence stratigraphy in glacially influenced basins: basic problems and water-level/glacier input-point controls (with an example from the Quaternary of Ontario, Canada). Sediment Geol 123:183–197
Eronen M, Glückert G, Hatakka L, van de Plassche O, van der Plicht J, Rantala P (2001) Rates of Holocene isostatic uplift and relative sea-level lowering of the Baltic in SW Finland based on studies of isolation contacts. Boreas 30:17–30
Ford JR, Price SJ, Cooper AH, Waters CN (2014) An assessment of lithostratigraphy for anthropogenic deposits. Geol Soc Lond Spec Publ 395:55–89
Fuller RA, Gaston KJ (2009) The scaling of green space coverage in European cities. Biol Letters 5:352–355
Gardemeister R (1975) On the engineering-geological properties of fine-grained sediments in Finland. Building technology and community development, Publications 9. Technical Research Centre of Finland, Helsinki, p 91
Hyvärinen H (1999) Shore displacement and stone age dwelling sites near Helsinki, southern coast of Finland. In: Huurre M (ed) Dig it all: papers dedicated to Ari Siiriäinen. Finnish Antiquarian Society. Archaeological Society of Finland, Helsinki, pp 79–89
Ignatius H, Kukkonen EA, Winterhalter BGL (1968) Notes on a pyritic zone in upper Ancylus sediments from the Bothnian Sea. Bull Geol Soc Finl 40:131–134
Ignatius H, Axberg S, Niemistö L, Winterhalter B (1981) Quaternary geology of the Baltic Sea. In: Voipio A (ed) The Baltic Sea. Elsevier, Amsterdam, pp 54–104
Kakkuri J (2012) Fennoscandian land uplift: past, present and future. In: Haapala I (ed) From the Earth’s core to outer space. Springer, Dordrecht, pp 127–136
Lepistö T (2013) Geophysical in situ measurements of soft soil for the purpose of adding stratigraphical interpretation. MSc thesis, Department of geosciences and geography, University of Helsinki, p 53
Loke MH, Barker RD (1996) Rapid least-squares inversion of apparent resistivity pseudosections by a qausi-Newton method. Geophys Prospect 44:131–162
Miettinen A, Savelieva L, Subetto DA, Dzhinoridze R, Arslanov K, Hyvärinen H (2007) Palaeoenvironment of the Karelian Isthmus, the easternmost part of the Gulf of Finland, during the Litorina Sea stage of the Baltic Sea history. Boreas 36:441–458
Ojala AEK (2007) Espoon Äijänpellon savikon stratigrafia ja geokemialliset piirteet. Geological Survey of Finland, Espoo, Open file Report P22.4/2007/26, 10 pp. [in Finnish] (Translated title: Sequence stratigraphy and geochemical characteristics of the Äijänpelto site in Espoo) http://arkisto.gsf.fi/p22/P22.4_2007_26.pdf
Ojala AEK (2009) Perkkaan ja Mustalahden alueiden hienorakeisten maalajien kerrosjärjestys ja ominaisuudet. Geological Survey of Finland, Espoo, Open file Report P22.4/2009/58, 24 pp. [in Finnish] (Translated title: Characteristics and stratigraphy of fine-grained deposits at the Perkkaa and Mustalahti sites in Espoo) http://tupa.gtk.fi/raportti/arkisto/p22_4_2009_58.pdf
Ojala AEK (2011) Construction suitability and 3D architecture of the fine-grained deposits in southern Finland—examples from Espoo. In: Nenonen K, Nurmi P (ed) Geoscience for Society—125th anniversary volume, Geological Survey of Finland, Espoo, Special Paper 49:205–212
Ojala AEK, Palmu J-P (2007) Sedimentological characteristics of Late-Weichselian–Holocene deposits of the Suurpelto area in Espoo, southern Finland. Geological Survey of Finland, Espoo, Special Paper 46:147–156
Ojala AEK, Ikävalko O, Palmu J-P, Vanhala H, Valjus T, Suppala I, Salminen R, Lintinen P, Huotari T (2007) Espoon Suurpellon alueen maaperän ominaispiirteet. Geological Survey of Finland, Espoo, Open file Report P22.4/2007/39, 51 pp. [in Finnish] (Translated title: Characteristics of Quaternary deposits at the Suurpelto construction site) http://arkisto.gsf.fi/p22/p22_4_2007_39.pdf
Ojala AEK, Palmu JP, Åberg A, Åberg S, Virkki H (2013) Development of an ancient shoreline database to reconstruct the Litorina Sea maximum extension and the highest shoreline of the Baltic Sea basin in Finland. Bull Geol Soc Finl 85:127–144
Räsänen ME, Auri JM, Huitti JV, Klap AK, Virtasalo JJ (2009) A shift from lithostratigraphic to allostratigraphic classification of Quaternary glacial deposits. GSA Today 19(2):4–11
Sharpe DR, Hinton MJ, Russel HAJ, Desbarats AJ (2002) The need for basin analysis in regional hydrogeological studies: Oak Ridges Moraine, southern Ontario. Geosci Can 29:3–20
Slomka JM, Eyles CH (2013) Characterizing heterogeneity in a glaciofluvial deposit using architectural elements, Limehouse, Ontario, Canada. Can J Earth Sci 50:911–929
Smelror M, Ahlstrøm A, Ekelund L, Hansen JM, Nenonen K, Mortensen AK (2008) The Nordic geological surveys: geology for society in practice. Episodes 31:193–200
Stapelfeldt T, Lojander M, Tanska H, Ojala A, Forsman J (2009) Deep stabilised test embankment at the Suurpelto area in Espoo, Southern Finland. In: Karstunen L, Leoni S (eds) Geotechnics of soft soils—focus on ground improvement. Taylor & Francis Group, London, pp 423–428
Stroeven AP, Hättestrand C, Kleman J, Heyman J, Fabel D, Fredin O, Goodfellow BW, Harbor JM, Jansen JD, Olsen L, Caffee MW, Fink D, Lundqvist J, Rosqvist GC, Strömberg B, Jansson KN (2016) Deglaciation of Fennoscandia. Quaternary Sci Rev 147:91–121
Törnqvist J (2008) Suurpellonsulfidisavien vaikutukset paalujen ja maanvastaisten betonilaattojen kestoikään ja teräsrakenteiden pysyvyyteen. Research report VTT-S-00621-08, Espoo, p 23
United Nations (2007) World urbanization prospects: the 2007 revision. In: United Nations 2007 New York, NY: United Nations, The Population Division of the Department of Economic and Social Affairs, p 66
Virtasalo JJ, Kotilainen AT, Räsänen ME, Ojala AEK (2007) Late-glacial and post-glacial deposition in a large, low relief, epicontinental basin: the northern Baltic Sea. Sedimentology 54:1323–1344
Virtasalo JJ, Hämäläinen J, Kotilainen AT (2014) Toward a standard stratigraphical classification practice for the Baltic Sea sediments: the CUAL approach. Boreas 43:924–938
Virtasalo JJ, Endler M, Moros M, Jokinen S, Hämäläinen J, Kotilainen A (2016) The base of brackish water mud as a stratigraphic surface in the Baltic Sea Basin. Geo-Mar Lett 36:445–456
Acknowledgements
Jukka-Pekka Palmu, Noora Kähkölä, Emilia Kosonen, and Susanna Kihlman are thanked for fruitful discussions and working with clayey successions in the Helsinki metropolitan area. Kirsti Keskisaari is acknowledged for technical support with maps and Catherine Cripps for constructive comments that improved the paper.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Ojala, A.E.K., Saresma, M., Virtasalo, J.J. et al. An allostratigraphic approach to subdivide fine-grained sediments for urban planning. Bull Eng Geol Environ 77, 879–892 (2018). https://doi.org/10.1007/s10064-016-0981-4
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10064-016-0981-4