Uwagi na temat budowy i rozwoju gipsów szklicowych

Abstract

REMARKS ON STRUCTURE AND DEVELOPMENT OF SZKLICA GYPSUM Summary Sediments called as szklica (Polish translation of "glassy") gypsum occur in Middle Miocene gypsum in the vicinities of Busko, Wiślica and Pińczów, southern margin of the Holy Cross Mts. They are built of vertically oriented gypsum crystals up to 3.5 m in height and forming intergrowths close to (TOI) twinnings, i.e. Paris twinnings. Views and premises concerning the question whether the gypsum is primary or secondary (due to recrystallization) in character are presented and it is shown that newly obtained data give further support to the hypothesis of primary origin of the gypsum. Vertically oriented gypsum crystals have been growing in competition with one another for free space and forming a fairly coherent horizon. Individual crystals were splitting out and forming skeletal forms. Load structures related to sinking or compactional squeezing of upwards growing crystals into not fully consolidated sediment occur in the base of the szklica gypsum. Masses of randomly oriented crystals, occurring in the szklica gypsum, originated crystals, occurring in the szklica gypsum, originated in times of growth of single crystals or isolated groups of crystals, accompanied by high-rate sedimentation of clays, and when the crystals were turned over due to increase in their weight and loss of equilibrium as well as activity of currents or waving. In the horizon of vertically oriented intergrowths, gypsum crystals display streaks of clays, very well traceable at the distance of about a dozen kilometers. The clay matter has been poikilitically entrapped by gypsum crystals during their growth.