DEGLACIATION IN EASTERN AND CENTRAL ... - arkisto.gsf.fi

Joint publications
9 I
Publications III and and VI are arejoint joint publications. publications. The contribution of ofthe the authors are as
follows: follows:
The material for paper III was collected collected by the the authors authors in the course of various
assignments, mainly the mapping of Quaternary deposits and the assessment of
gravel resources. The contributions of of Rainio Rainio and Lahermo were made specifically specifrcally
with this study study in mind in connection with with the investigation investigation of the Central Finland
ice-marginal formation. The observations observations of Kejonen Kejonen and Kielosto derive mainly
from the western western part and and those of of Rainio and and Lahermo from the eastern part of the
area. The The bulk of the the paper was compiled and written by Rainio.
The authors authors ofpaper of paper VI participated participated in in studies on the Younger Dryas end moraines
between Hanko and Kem in Russian Russian Karelia, Karelia, and the overall overall picture is a
combination combination of of their views. Rainio Rainio dealt dealt mainly mainly with the ice-marginal deposits in
Finnish North Karelia and and their their relation relation to the other parts parts of the ice-marginal
landform landform chains. Saarnisto Saarnisto alone is responsible for for the discussion of late-glacial
hydrology. hydrology.
INTRODUCTION
General
The The bedrock bedrock of of southern southern Finland is is composed of crystalline palaeo-Proterozoic rocks.
The The easternmost easternmost part of the bedrock, east east of the the Pielinen-Värtsilä area, is of older,
Archaean Archaean origin.
In the southernmost southernmost part of of southern Finland the local local variation in elevation is
slight, usually no no more than than a few tens of metres. In In central and eastern Finland,
the variation is greater but still seldom over 100 m. Movements Movements of the continental
ice sheet were probably affected most by the ridges in the Koli-Värtsilä area, where
the maximum variation in elevation elevation is 200-250 m.
Southern Finland was largely largely subaquatic at the the end of glaciation. That there were
large supra-aquatic areas in central and eastern eastern Finland is revealed by the
distribution of glacial and postglacial postglacial deposits (Kujansuu & Niemelä, 1984), which
clearly clearly depends on whether the area was supra- supra- or subaquatic. The occurrence and
structure of the Salpausselkäs and and the Central Finland Finland end moraine moraine were also
affected by the position of the front of the ice sheet at which which they deposited, i.e.
whether it was on land or in water (Ramsay, 1921; Rainio & Lahermo, 1985; Eronen
& Vesajoki, 1988).