UWAGI DO POGLĄDÓW NA GENEZĘ PEGMATYTÓW STRZEGOMSKICH OPARTE NA BADANIACH INKLUZJI FLUIDALNYCH W KRYSZTAŁACH KWARCU Z KOLEKCJI MUZEUM GEOLOGICZNEGO PIG-PIB

Abstract

REMARKS TO VIEWS ON THE STRZEGOM PEGMATITES GENESIS BASED ON FLUID INCLUSIONS ANALYSIS OF QUARTZ CRYSTALS FROM THE PGI-NRI MUSEUM COLLECTION

Abstract. Fluid inclusions in quartz found in the Strzegom pegmatites (Sudety Mts, S Poland) were investigated. The samples are located at the PGI Museum in Warsaw. They come from pegmatite druses of pneumatolytic-hydrothermal origin. Fluid inclusions in grey quartz, smoky quartz, morion and rock-crystal were examined. The widest temperature spectrum was obtained within the oldest grey quartz which is massive, not-transparent and often strongly fractured. Homogenization temperatures fall within the interval from 100 to 550°C. Such a wide range is due to intergrowths of different quartz generations of the grey type. The majority of inclusions, in which the homogenization can be seen, exhibit temperatures lower than 200°C. They are associated with the regeneration of older quartz generations. These inclusions are filled in with brines containing NaCl–CaCl₂. Fluid inclusions, in which homogenization occurs in the temperature interval of 200–240°C, most probably define rock-crystal quartz crystallization. A crystallization range of smoky quartz and morion was calculated at 200–300°C. The composition of fluid is controversial. The highest temperature inclusions homogenize to the liquid phase at the temperatures of 327.8 to 407.8°C. Homogenization in the gas phase is noticed in some oval and polygonal inclusions at the temperatures of 342–550°C. A pneumatolitic stage, in which grey quartz was created, is probably documented by part of these inclusions.