Bąk, K., 1991/1992. Petrographic composition and conditions of sedimentation of the lacustrine sediments in the High Tatra Mountains. Studia Geomorphologica Carpatho-Balcanica, 21/22: 151-161.

Abstract: In this paper further results of research on lacustrine deposits revealed in the High Tatra Mountains are presented. Studies were carried out under the direction of M. Baumgart-Kotarba and A. Kotarba. The samples of deposits have been taken from four shallow borings sunken in the lakes Zielony Staw Gąsienicowy and Czarny Staw Gąsienicowy, and from the bottom of the Czerwony Staw Lake occurring in the Gąsienicowa Dolina Valley. The detailed description of the boring techniques and the first research results (content of organic substance, sedimentological structure, density, grain size distribution) have already been presented by Baumgart-Kotarba, Jonasson & Kotarba (1990). This paper contains an analysis of the mineralogical composition of lacustrine deposits. It also tries to explain the mechanism of material sedimentation in the lakes. Both the mineralogical composition and the roundness degree of muscovite found in the Czarny Staw Gąsienicowy Lake and Zielony Staw Gąsienicowy Lake indicate differences in the mechanism of sedimentation there. In the Zielony Staw Gąsienicowy Lake, the high mica content which coincides with low value of sandy fraction confirms the lower energy of material supply into the central part of the lake. The more mineral layers being interpreted as turbidity deposits (Baumgart-Kotarba et al. 1990) are characterised by a higher quartz and feldspar content and by a greater roundness degree of muscovite. The more organic intercalations are marked by higher values of micas and by very low roundness degree. These features may confirm an occurrence of periods of a quiet sedimentation, with a respectively increasing eolian transport to the lake. However, it is difficult to estimate its rate. The more intensive material supply into the Czarny Staw Gąsienicowy Lake is indicated by high quartz and feldspar content (even up to 90%). In the profile, the content of micas in the fraction 0.125-0.063 mm may suggest a transport in suspension of this grain size. This is well seen in the cores A and C and confirmed by the nature of the present-day suspended material which was analysed at the model site, i.e. at the Czerwony Staw Lake. The respectively high roundness degree of muscovite, together with a low content of organic layers rather contradicts the important role played by aeo1ian transport in the material supply into the lake.