A contribution to Holocene shore displacement and environmental development in Vantaa, South Finland: the stratigraphy of Lake Lammaslampi

Abstract

The sediments of Lammaslampi, a small lake situated about 32 m a.s.l. in Vantaa, were studied by means of pollen and diatom analyses and loss-on-ignition measurements. In addition x-ray diffraction analysis was used to examine the mineral composition of the basal part of the profile, and five radiocarbon determinations to date the local shoreline displacement. The basin was continuously connected to the Baltic until it became isolated as the result of the isostatic uplift after the Litorina transgression 6 550 ± 170 C 14 years BP. The »early Mastogloia phase» in the region was dated to c. 7 700 BP and the beginning of the Litorina stage to c. 7 300 BP.

The Mastogloia stage in the Baltic Sea history: diatom evidence from southern Finland

“…The limit shown here corresponds to the highest topographical occurrence of postAncylus brackish sediments and indicates the general position of the shoreline between about 8000 and 7000 B.P. For more details of the local shoreline displacement, see Alhonen et al 1978, Hyvärinen 1979, 1980, 1982, and Eronen & Haila 1982 Most of the stratigraphical data used here have been published in the papers mentioned above. In addition to the previous sites, there are three new sites, for which pollen and diatom diagrams are appended.…”

“…Lammaslampi (Alhonen et al 1978), alt. 31.8 m, size 6 ha, depth at coring site 3 m, core length 5.2 m. Stratigraphy (the original paper gives depths below water level; the present paper gives depths below the sediment surface, as in the other sites): 0-300 cm, gyttja; 300-320 cm, clay-gyttja; 320-400 cm, gyttja; 400-480 cm, clay-gyttja; 480-520 cm, clayey-silt.…”

Stratigraphical studies on Lake Iidesjärvi sediments. Part II. Geological and mineralogical characteristics of the sedimentary sequence

“…e.g. Soveri 1956;Sippola 1974;Gardemeister 1975 andAlhonen et al 1978). As to the residual, fine-grained and unweathered rock-forming minerals, quartz, plagioclase, potassic feldspar and amphibole were present in all samples throughout the sedimentary sequence of Lake Iidesjärvi, with quartz being the dominant mineral and amphibole and potassic feldspar the least abundant.…”

“…Vermiculite has been found in the bottom deposits of Lake Iidesjärvi, since the lower part of the column studied, and its presence both as such and as a member of mixed layer illite-vermiculite, is somewhat higher than in most other areas studied (cf. Gardemeister 1975 andAlhonen et al 1978). This is probably due to the micarich bedrock in the environment and the relatively easy wheatherability of biotite to the »hydromica» stage, i.e.…”

Late-Holocene shore displacement of the Finnish south coast: diatom, litho- and chemostratigraphic evidence from three isolation basins

“…In the Helsinki area there are many observations of the raised Litorina shore formations at the altitude of c. 30-34 m a.s.l. (Hyyppä 1937;Sauramo 1958) and the lake-sedimentological evidence suggest either a standstill (Hyvärinen 1980(Hyvärinen , 1982 or a slight transgression of the sea level (Alhonen et al 1978;Glückert 1991;Korhola 1995). Unambiguous lake-sedimentological evidence for the transgressive nature of the Litorina Sea comes from the coast east of Helsinki where the land uplift rate is slower (Eronen 1974;Miettinen & Hyvärinen 1997).…”