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Seismic refraction investigations in Poland (1964-1978) and their use in continuing studies

Młynarski S.

Geological Quarterly

2002

Vol. 46, No 3

247-254

Seismic refraction investigations, performed in Poland between 1964 and 1978, are reviewed. Examples selected from the many seismic profiles, totalling approximately 15 000 km in length, are shown. The most useful profiles as regards geological interpretation are in the Precambrian Platform and along its southwestern edge. Both the top of the crystalline basement and a system of faults, downfaulting the basement towards the south-west, can be identified in that area. In the Carpathians and its foreland, the top of this basement may be identified together with the bases of thrust flysch nappes. In the Fore-Sudetic Monocline, the top of folded Carboniferous deposits can be determined. The most ambiguous results were obtained from the Palaeozoic Platform.

On the thermal properties of the Baltic Shield upper mantle

Maj S.

Acta Geophysica Polonica

2001

Vol. 49, nr 3

343-359

A simple temperature model of the crust and upper mantle in the Baltic Shield (BS) area related to the southern/central Finland is considered. Its surface part contains the crystalline rocks only. The depth of the Moho discontinuity is about 45 km. Some physical conditions of the BS model are as follow: surface heat flow density Q = 40 mW/m2, surface radiogenic heat production A0 = 4.0 miW/m3, parameter D = 5 km, reduced heat flow density qr = 20 mW/m2. Results of calculations suggest that the vertical heat flow density at the Moho discontinuity is about 20 mW/m2 and geothermal gradients arc 10 K/km on the side of the lower crust and 8 K/km on the side of the upper mantle. Temperatures within the BS upper mantle model increase from about 703 K at the Moho to about 2600 K at a depth of 1000 km. The effective thermal conductivity within the Low-Velocity Layer is about 5 W/m K.