Geological Survey of Finland, Special Paper 46 - arkisto.gsf.fi

Applied Quaternary research in the central part of glaciated terrain,
edited by Peter Johansson and Pertti Sarala.
Geological Survey of Finland, Special Paper 46, 63–68, 2007.
SPATIAL DISTRIBUTION AND MORPHOLOGICAL ASPECTS
OF ESKERS AND BEDROCK VALLEYS IN NORTH ESTONIA:
IMPLICATIONS FOR THE RECONSTRUCTION OF A SUBGLACIAL
DRAINAGE SYSTEM UNDER THE LATE WEICHSELIAN BALTIC ICE
STREAM
by
Maris Rattas 1
Rattas. M. 2007. Spatial distribution and morphological aspects
of eskers and bedrock valleys in north Estonia: implications for
the reconstruction of a subglacial drainage system under the Late
Weichselian Baltic Ice Stream. Applied Quaternary research in
the central part of glaciated terrain. Geological Survey of Finland,
Special Paper 46, 63–68, 4 fi gures.
The spatial distribution of eskers and bedrock valleys, their
antecedent role in draining subglacial meltwater and their relationship
to bedrock lithology are discussed. Bedrock valleys and
eskers are arranged in a sub-parallel pattern refl ecting former
meltwater fl ow towards the ice margin. Several esker systems
are confi ned to the valley limits following either the valley fl oors
or lying upon their shoulders. Such spatial relationships suggest
that the initial focusing of meltwater may have been controlled
by the location of bedrock valleys. Alternatively, some of the
buried valleys or segments of valleys may be the result of tunnel
valley formation. Some valleys have clear morphological characteristics
of a tunnel valley, like abrupt termination and undulating
or convex-up longitudinal profi les. Sedimentary records suggest
that some valley infi ll and esker sediments may have been developed
as a successive formation.
Key words (GeoRef Thesaurus, AGI): glacial geology, subglacial
environment, meltwater, drainage patterns, eskers, valleys, Pleistocene,
Weichselian, Estonia.
1 Institute of Geology, University of Tartu, Vanemuise 46,
EE-51014, Tartu, Estonia
E-mail: maris.rattas@ut.ee
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