Automorficzne kryształy kwarcu z wysadu solnego Wapna

Abstract

Euhedral quartz crystals from salt diapir nearWapno (central Poland).Summary. Euhedral quartz crystals were discovered in rocks forming top of Wapno diapir (North Poland) by drilling. Quartz crystals were found in: 1) Tertiary [Paleogene? Neogene?] sands covering gypsum cap-rock, 2) gypsum forming cap-rock and 3) Late Permian salts. Three forms of quartz crystals were distinguished: a) single, euhedral crystals of short pseudohexagonal prisms terminated by rhombohedrons equally developed on both ends (0.5–2.0 mm long), b) aggregates of few crystals terminated by rhombohedrons (up to 2 mm of diameter) and c) “rosettes” in which perfectly terminated crystals radiate in all directions (max. diameter 2.0 mm). A few single quartz crystals contain inclusions of anhydrite. The origin of quartz crystals is discussed and model of quartz crystallization in evaporate basin is presented. The host rock of quartz could be salt and after salt dissolution, the crystals were embedded in cap-rock gypsum. The presence of euhedral quartz crystals in sands covering cap-rock can be simply explained by dissolution of cap-rock gypsum. It means that quartz crystals in sands are a residual compound.