Source of K-Feldspars in Arkoses and Their Kaolinitization in the Bohemian Upper Carboniferous Basins (Czech Republic)

Jiranek J and Klominsky J

Published on: 2024-03-30

Abstract

The K-feldspars in arkoses of the continental Upper Carboniferous West and Central Bohemian basins originated in the whole bed sequence (Duckmantian to Autunian; 314.2–297.1 Ma) from one source, which were so-called mountain granites of the older intrusive complex (OIC) of the Krusne hory Mts, as confirmed by the X-ray and geochemical investigations. The presence of feldspar clasts from other granitoids (Merklin and Louny massifs) is limited to the directly transgressing basal Carboniferous rocks. While many arkoses underwent synsedimentary and/or post-sedimentary kaolinization, in the main kaolin deposits of the Nyrany Member of the Kladno Formation (Kaznejov and Horni Briza), pre-sedimentary kaolinization (sedimentation of sandstones and conglomerates with kaolinitic cement) occurred.