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

Geological Survey of Finland, Special Paper 46
Danguol Karmazien, Bronislavas Karmaza and Valentinas Baltrünas
The North Lithuanian region has been known as a
zone of dominant glacial erosion where the Quaternary
sediment cover is relatively thin (up to 40
m in palaeoincisions) and has a specifi c structure
(Bucevic v
i0te . et al. 1992, and others). Previous research
has shown that the character of glacial erosion
and glacial material transportation are refl ected
in the structure of Pleistocene deposits, particularly
in tills. The aim of the present paper is to report
new information on structural peculiarities of North
Lithuanian Pleistocene strata. The new data were
obtained using different methods of studying Pleistocene
deposits in the adjacent dolomite quarries
near the Petraši0nai and the Klovainiai boroughs
in the Pakruojis District (Fig. 1). These quarries
are 7–8 km away from each other. About 5–6 km
north of the Petraši0nai quarry, is the boundary of
the North Lithuanian Phase of the Baltic Stage and
is marked by a distinct morainic Linkuva ridge.
Macroscopic description, graphic fi xation and photography
of the quarry walls were used to examine
the Pleistocene succession the study site. Granulometric
analysis of intertill silt served as a basis for
stratigraphic classifi cation of the Pleistocene strata.
The following fractions were determined: 5–2; 2–1;
1–0.5; 0.5–0.25; 0.25–0.1; 0.1–0.05; 0.05–0.01;
0.01–0.005; 0.005–0.002; 0.002–0.001 and